Globalization and disease
Encyclopedia
Globalization
, the flow of information, goods, capital and people across political and geographic boundaries, has helped to spread some of the deadliest infectious diseases known to humans. The spread of diseases across wide geographic scales has increased through history. Early diseases that spread from Asia to Europe were bubonic plague, influenza of various types, and similar infectious disease.
In the current era of globalization, the world is more interdependent than at any other time. Efficient and inexpensive transportation has left few places inaccessible, and increased global trade in agricultural products has brought more and more people into contact with animal diseases that have subsequently jumped species
barriers (see zoonosis
).
Globalization intensified during the Age of Exploration
, but trading routes had long been established between Asia and Europe, along which diseases were also transmitted. An increase in travel has helped spread diseases to natives of lands who had not previously been exposed. When a native
population is infected with a new disease, where they have not developed antibodies through generations of previous exposure, the new disease tends to run rampant within the population.
Etiology
, the modern branch of science
that deals with the causes of infectious disease
, recognizes five major modes of disease transmission: airborne, waterborne, bloodborne, by direct contact, and through vector (insect
s or other creatures that carry germs from one species to another). As humans began traveling over seas and across lands which were previously isolated, research suggests that diseases have been spread by all five transmission modes.
generally refers to the period between the 15th and 17th centuries. During this time, technological advances in shipbuilding
and navigation made it easier for nations to explore outside previous boundaries. Globalization has had many benefits, for example, new products to European
s were discovered, such as tea
, silk
and sugar
when Europeans developed new trade routes around Africa
to India
and the Spice Islands
, Asia
, and eventually running to the Americas
.
In addition to trading in goods, many nations began to trade in slavery
. Trading in slaves was another way by which diseases were carried to new locations and peoples, for instance, from sub-Saharan Africa to the Caribbean and the Americas. During this time, different societies began to integrate, increasing the concentration of human
s and animal
s in certain places, which led to the emergence of new diseases as some jumped in mutation from animals to humans.
During this time sorcerers' and witch doctor
s' treatment of disease was often focused on magic
and religion
, and healing the entire body
and soul
, rather than focusing on a few symptoms like modern medicine. Early medicine often included the use of herbs and meditation
. Based on archeological evidence, some prehistoric practitioners in both Europe and South America used trephining, making a hole in the skull to release illness. Severe diseases were often thought of as supernatural
or magical. The result of the introduction of Eurasian diseases to the Americas was that many more native peoples were killed by disease and germs
than by the colonists' use of guns or other weapons. Scholars estimate that over a period of four centuries, epidemic diseases wiped out as much as 90 percent of the American indigenous populations.
In Europe during the age of exploration, diseases such as smallpox
, measles
and tuberculosis
(TB) had already been introduced centuries before through trade with Asia and Africa. People had developed some antibodies to these and other diseases from the Eurasian continent. When the Europeans traveled to new lands, they carried these diseases with them. (Note: Scholars believe TB was already endemic in the Americas.) When such diseases were introduced for the first time to new populations of humans, the effects on the native populations were widespread and deadly. The Columbian Exchange
, referring to Christopher Columbus
's first contact with the native peoples of the Caribbean
, began the trade of animals, and plants, and unwittingly began an exchange of diseases.
It was not until the 1800s that humans began to recognize the existence and role of germs and microbes in relation to disease. Although many thinkers had ideas about germs, it was not until Louis Pasteur
spread his theory about germs, and the need for washing hands and maintaining sanitation
(particularly in medical practice), that anyone listened. Many people were quite skeptical, but on May 22, 1881 Pasteur persuasively demonstrated the validity of his germ theory of disease with the first successful vaccination
. The anthrax
vaccine was administered to 25 sheep while another 25 were used as a control. On May 31, 1881 all of the sheep were exposed to anthrax. While every sheep in the control group died, each of the vaccinated sheep survived. Pasteur’s experiment would become a milestone in disease prevention. His findings, in conjunction with other vaccines that followed, changed the way globalization affected the world.
around the world at a faster pace; they also open the airways to the transcontinental movement of infectious disease vectors. One example is the West Nile Virus
. It is believed that this disease reached the United States
via “mosquitoes that crossed the ocean by riding in airplane wheel wells and arrived in New York City in 1999.” With the use of air travel, people are able to go to foreign lands, contract a disease and not have any symptoms of illness until after they get home, and having exposed others to the disease along the way.
As medicine has progressed, many vaccines and cures have been developed for some of the worst diseases (plague, syphilis, typhus, cholera, malaria) which people suffer. But, because the evolution
of disease organisms is very rapid, even with vaccines, there is difficulty providing full immunity
to many diseases. Finding vaccines at all for some diseases remains extremely difficult. Without vaccines, the global world remains vulnerable to infectious diseases.
Evolution of disease presents a major threat in modern times. For example, the current "swine flu" or H1N1 virus is a new strain of an old form of flu, known for centuries as Asian flu based on its origin on that continent. From 1918-1920, a post-World War I
global influenza epidemic killed an estimated 50-100 million people, including half a million in the United States alone. H1N1 is a virus that has evolved from and partially combined with portions of avian, swine, and human flu.
Globalization has increased the spread of infectious diseases from South to North, but also the risk of non-communicable diseases by transmission of culture and behavior from North to South. It is important to target and reduce the spread of infectious diseases in developing countries. However, addressing the risk factors of non-comunicable diseases and lifestyle risks in the South that cause disease, such as use or consumption of tobacco, alcohol, and unhealthy foods, is important as well.
is a variant of the deadly flea
-borne disease plague
, which is caused by the enterobacteria Yersinia pestis
, that devastated human populations beginning in the 14th century. Bubonic plague is primarily spread by fleas that lived on the black rat
, an animal that originated in south Asia and spread to Europe by the 6th century. It became common to cities and villages, traveling by ship with explorers. A human would become infected after being bitten by an infected flea. The first sign of an infection of bubonic plague is swelling of the lymph nodes, and the formation of buboes. These buboes would first appear in the groin or armpit area, and would often ooze pus
or blood
. Eventually infected individuals would become covered with dark splotches caused by bleeding under the skin. The symptoms would be accompanied by a high fever
, and within four to seven days of infection, more than half the victims would die. During the 14th and 15th century, humans did not know that a bacterium was the cause of plague, and efforts to slow the spread of disease were futile.
The first recorded outbreak of plague occurred in China
in the 1330s, a time when China was engaged in substantial trade with western Asia and Europe. The plague reached Europe in October 1347. It was thought to have been brought into Europe through the port of Messina, Sicily
, by a fleet of Genoese trading ships from Kaffa
, a seaport on the Crimean peninsula. When the ship left port in Kaffa, many of the inhabitants of the town were dying, and the crew was in a hurry to leave. By the time the fleet reached Messina, all the crew were either dead or dying; the rats that took passage with the ship slipped unnoticed to shore and carried the disease with them and their fleas.
Within Europe, the plague struck port cities first, then followed people along both sea and land trade routes. It raged through Italy
into France
and the British Isles
. It was carried over the Alps
into Switzerland
, and eastward into Hungary
and Russia
. For a time during the 14th and 15th centuries, the plague would recede. Every ten to twenty years, it would return. Later epidemics, however, were never as widespread as the earlier outbreaks, when nearly a third of the population died.
The plague has never died out. From 1896-1918 the plague swept through India, taking the lives of over 12.5 million people. Between 1906 and 1914, the Plague Research Commission was created, and published supplements to the Journal of Hygiene.
is a highly contagious airborne virus
spread by contact with infected oral and nasal fluids. When a person with measles coughs or sneezes, he releases microscopic particles into the air. During the 4-12 day incubation period
, an infected individual shows no symptoms, but as the disease progresses, the following symptoms appear: runny nose, cough, red eyes, extremely high fever and a rash.
Measles is an endemic disease, meaning that it has been continually present in a community, and many people develop resistance. In populations that have not been exposed to measles, exposure to the new disease can be devastating. In 1529, a measles outbreak in Cuba
killed two-thirds of the natives who had previously survived smallpox. Two years later measles was responsible for the deaths of half the indigenous population of Honduras
, and ravaged Mexico
, Central America
, and the Inca civilization.
Historically, measles was very prevalent throughout the world, as it is highly contagious. According to the National Immunization Program, 90% of people were infected with measles by age 15, acquiring immunity to further outbreaks. Until a vaccine was developed in 1963, measles was considered to be deadlier than smallpox. Vaccination reduced the number of reported occurrences by 98%. Major epidemics have predominantly occurred in unvaccinated populations, particularly among nonwhite Hispanic
and African American
children under 5 years old. In 2000 a group of experts determined that measles was no longer epidemic in the United States. The majority of cases that occur are among immigrants from other countries.
, which is transmitted to humans through lice. The main vector for typhus
is the rat flea
. Flea bites and infected flea feces in the respiratory tract are the two most common methods of transmission. In areas where rats are not common, typhus may also be transmitted through cat
and opossum fleas. The incubation period
of typhus is 7–14 days. The symptoms start with a fever
, then headache, rash
, and eventually stupor
. Spontaneous recovery occurs in 80-90% of victims.
The first outbreak of typhus was recorded in 1489. Historians believe that troops from the Balkans
, hired by the Spanish army, brought it to Spain with them. By 1490 typhus traveled from the eastern Mediterranean into Spain
and Italy
, and by 1494, it had swept across Europe. From 1500-1914, more soldiers were killed by typhus than from all the combined military
actions during that time. It was a disease associated with the crowded conditions of urban poverty and refugees as well. Finally, during World War I
, governments instituted preventative delousing measures among the armed forces and other groups, and the disease began to decline. The creation of antibiotic
s has allowed disease to be controlled within two days of taking a 200 mg dose of tetracycline.
that causes open sores, delirium
and rotting skin, and is characterized by genital ulcer
s. Syphilis can also do damage to the nervous system, brain and heart. The disease can be transmitted from mother to child.
The origins of syphilis
are unknown, and some historians argue that it descended from a twenty-thousand-year-old African zoonosis
. Other historians place its emergence in the New World
, arguing that the crews of Columbus’s ships first brought the disease to Europe
. The first recorded case of syphilis occurred in Naples
in 1495, after King Charles VIII
of France besieged the city of Naples, Italy
. The soldiers, and the prostitutes who followed their camps, came from all corners of Europe. When they went home, they took the disease with them and spread it across the continent.
is a highly contagious disease caused by the Variola virus. There are four variations of smallpox; variola major, variola minor, haemorrhagic, and malignant, with the most common being variola major and variola minor. Symptoms of the disease including hemorrhaging, blindness
, back ache, vomiting
, which generally occur shortly after the 12-17 day incubation period. The virus begins to attack skin
cells, and eventually leads to an eruption of pimples that cover the whole body. As the disease progresses, the pimples fill up with pus or merge together. This merging results in a sheet that can detach the bottom layer from the top layer of skin. The disease is easily transmitted through airborne pathways (coughing, sneezing, and breathing), as well as through contaminated bedding, clothing or other fabrics,
It is believed that smallpox first emerged over 3000 years ago, probably in India
or Egypt
. There have been numerous recorded devastating epidemic
s throughout the world, with high losses of life.
Smallpox was a common disease in Eurasia in the 15th century, and was spread by explorers
and invaders. After Columbus landed on the island of Hispaniola
during his second voyage in 1493, local people started to die of a virulent infection
. Before the smallpox epidemic started, more than one million indigenous people had lived on the island
; afterward, only ten thousand had survived.
During the 16th century, Spanish soldiers introduced smallpox by contact with natives of the Aztec
capital Tenochtitlan. A devastating epidemic broke out among the indigenous people, killing thousands.
In 1617, smallpox reached Massachusetts
, probably brought by earlier explorers to Nova Scotia
, Canada
.” By 1638 the disease had broken out among people in Boston, Massachusetts. In 1721 people fled the city after an outbreak, but the residents spread the disease to others throughout the thirteen colonies
. Smallpox broke out in six separate epidemics in the United States through 1968.
The smallpox vaccine
was developed in 1798 by Edward Jenner
. By 1979 the disease had been completely eradicated
, with no new outbreaks. The WHO
stopped providing vaccinations and by 1986, vaccination was no longer necessary to anyone in the world except in the event of future outbreak. Currently the smallpox virus exists only in laboratories (25).
, also known as Hansen’s Disease, is caused by a bacillus
, Mycobacterium leprae
. It is a chronic disease with an incubation period of up to five years. Symptoms often include irritation or erosion of the skin, and affects on the peripheral nerves, mucosa of the upper respiratory tract and eyes. The most common sign of leprosy are pale reddish spots on the skin that lack sensation.
Leprosy probably originated in India
, more than four thousand years ago. It was prevalent in ancient societies in China
, Egypt and India, and was transmitted throughout the world by various traveling groups, including Roman Legion
naires, Crusaders
, Spanish conquistador
s, Asian seafarers, European colonists, and Arab, African, and American slave traders. Some historians believe that Alexander the Great's troops brought leprosy from India to Europe during the 3rd century BC. With the help of the crusaders and other travelers, leprosy reached epidemic
proportions by the 13th century.
Once detected, leprosy can be cured using multi-drug therapy (MDT), composed of two or three antibiotics, depending on the type of leprosy. In 1991 the World Health Assembly began an attempt to eliminate leprosy. By 2005 116 of 122 countries were reported to be free of leprosy.
(then called "Marsh Fever") was a protozoan parasite, and that mosquitoes carry and transmit malaria. Malaria is a protozoan infectious disease
that is generally transmitted to humans by mosquitoes between dusk and dawn. The European variety, known as "vivax" after the Plasmodium vivax
parasite, causes a relatively mild, yet chronically aggravating disease. The west African variety is caused by the sporozoan parasite, Plasmodium falciparum
, and results in a severely debilitating and deadly disease.
In 1492, malaria
was a disease endemic
to Europe
and Western Africa. The variety from West Africa, Plasmodium falciparum, became a threat to colonists and indigenous people alike when it was introduced into the Americas through Africans transported in the slave trade. It is now endemic to tropical areas.
Parts of the Third World
are more affected by malaria than the rest of the world. For instance, many inhabitants of sub-Saharan Africa are affected by recurring attacks of malaria throughout their lives. In many areas of Africa, there is limited running water
. The residents' use of wells and cistern
s provides many sites for the breeding of mosquitoes and spread of the disease. Mosquitoes use areas of standing water like marshes, wetlands, and water drums to breed.
, Mycobacterium tuberculosis
, is generally spread when an infected person cough
s and another person inhales the bacteria. Once inhaled TB frequently grows in the lungs, but can spread to any part of the body. Although TB is highly contagious, in most cases the human body is able to fend off the bacteria. But, TB can remain dormant
in the body for years, and become active unexpectedly. If and when the disease does become active in the body, it can multiply rapidly, causing the person to develop many symptoms including cough (sometimes with blood), night sweats, fever, chest pains, loss of appetite and loss of weight. This disease can occur in both adults and children and is especially common among those with weak or undeveloped immune system
s.
Tuberculosis (TB) has been one of history’s greatest killers, taking the lives of over 3 million people annually. It has been called the "white plague". According to the WHO, approximately fifty percent of people infected with TB today live in Asia
. It is the most prevalent, life-threatening infection among AIDS
patients. It has increased in areas where HIV seroprevalence
is high.
Air travel
and the other methods of travel which have made global interaction easier, have increased the spread of TB across different societies. Luckily, the BCG vaccine
was developed, which prevents TB meningitis and miliary TB in childhood. But, the vaccine does not provide substantial protection against the more virulent forms of TB found among adults. Most forms of TB can be treated with antibiotics to kill the bacteria. The two antibiotics most commonly used are rifampicin
and isoniazid
. There are dangers, however, of a rise of antibiotic-resistant TB. The TB treatment regimen is lengthy, and difficult for poor and disorganized people to complete, increasing resistance of bacteria.
, it is unknown where the HIV
virus
originated, but it appeared to move from animals to humans. It may have been isolated within many groups throughout the world. It is believed that HIV arose from another, less harmful virus, that mutated and became more virulent. The first two AIDS/HIV cases were detected in 1981. As of 2004, an estimated 1,039,000 to 1,185,000 persons in the United States
were living with HIV/AIDS, and an estimated 39.5 million people worldwide are living with HIV
”. The WHO also reports that there has been a 50% increase in HIV-infected people since 2004. Despite efforts in numerous countries, awareness and prevention programs have not been effective enough to reduce the numbers of new HIV cases in many parts of the world, where it is associated with high mobility of men, poverty and sexual mores among certain populations. Uganda has had an effective program, however. Until recently, the South African government refused to mount strong preventive or education programs. Prevention programs are difficult to maintain and, as a result, the protective measures usually do not last long after the program stops.
can also benefit people with non-communicable diseases such as heart problems or mental health problems. Global trade and rules set forth by the World Trade Organization
can actually benefit the health of people by making their incomes higher, allowing them to afford better health care. Also the national income of a country, mostly obtained by trading on the global market, is important because it dictates how much a government spends on health care for its citizens. Although poorer countries have not yet experienced this and are still suffering from diseases listed above.
Globalization
Globalization refers to the increasingly global relationships of culture, people and economic activity. Most often, it refers to economics: the global distribution of the production of goods and services, through reduction of barriers to international trade such as tariffs, export fees, and import...
, the flow of information, goods, capital and people across political and geographic boundaries, has helped to spread some of the deadliest infectious diseases known to humans. The spread of diseases across wide geographic scales has increased through history. Early diseases that spread from Asia to Europe were bubonic plague, influenza of various types, and similar infectious disease.
In the current era of globalization, the world is more interdependent than at any other time. Efficient and inexpensive transportation has left few places inaccessible, and increased global trade in agricultural products has brought more and more people into contact with animal diseases that have subsequently jumped species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
barriers (see zoonosis
Zoonosis
A zoonosis or zoonoseis any infectious disease that can be transmitted from non-human animals to humans or from humans to non-human animals . In a study of 1415 pathogens known to affect humans, 61% were zoonotic...
).
Globalization intensified during the Age of Exploration
Age of Discovery
The Age of Discovery, also known as the Age of Exploration and the Great Navigations , was a period in history starting in the early 15th century and continuing into the early 17th century during which Europeans engaged in intensive exploration of the world, establishing direct contacts with...
, but trading routes had long been established between Asia and Europe, along which diseases were also transmitted. An increase in travel has helped spread diseases to natives of lands who had not previously been exposed. When a native
Indigenous peoples
Indigenous peoples are ethnic groups that are defined as indigenous according to one of the various definitions of the term, there is no universally accepted definition but most of which carry connotations of being the "original inhabitants" of a territory....
population is infected with a new disease, where they have not developed antibodies through generations of previous exposure, the new disease tends to run rampant within the population.
Etiology
Etiology
Etiology is the study of causation, or origination. The word is derived from the Greek , aitiologia, "giving a reason for" ....
, the modern branch of science
Science
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...
that deals with the causes of infectious disease
Infectious disease
Infectious diseases, also known as communicable diseases, contagious diseases or transmissible diseases comprise clinically evident illness resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism...
, recognizes five major modes of disease transmission: airborne, waterborne, bloodborne, by direct contact, and through vector (insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s or other creatures that carry germs from one species to another). As humans began traveling over seas and across lands which were previously isolated, research suggests that diseases have been spread by all five transmission modes.
Travel patterns and globalization
The Age of ExplorationAge of Discovery
The Age of Discovery, also known as the Age of Exploration and the Great Navigations , was a period in history starting in the early 15th century and continuing into the early 17th century during which Europeans engaged in intensive exploration of the world, establishing direct contacts with...
generally refers to the period between the 15th and 17th centuries. During this time, technological advances in shipbuilding
Shipbuilding
Shipbuilding is the construction of ships and floating vessels. It normally takes place in a specialized facility known as a shipyard. Shipbuilders, also called shipwrights, follow a specialized occupation that traces its roots to before recorded history.Shipbuilding and ship repairs, both...
and navigation made it easier for nations to explore outside previous boundaries. Globalization has had many benefits, for example, new products to European
European ethnic groups
The ethnic groups in Europe are the various ethnic groups that reside in the nations of Europe. European ethnology is the field of anthropology focusing on Europe....
s were discovered, such as tea
Tea
Tea is an aromatic beverage prepared by adding cured leaves of the Camellia sinensis plant to hot water. The term also refers to the plant itself. After water, tea is the most widely consumed beverage in the world...
, silk
Silk
Silk is a natural protein fiber, some forms of which can be woven into textiles. The best-known type of silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity...
and sugar
Sugar
Sugar is a class of edible crystalline carbohydrates, mainly sucrose, lactose, and fructose, characterized by a sweet flavor.Sucrose in its refined form primarily comes from sugar cane and sugar beet...
when Europeans developed new trade routes around Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
to India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
and the Spice Islands
Maluku Islands
The Maluku Islands are an archipelago that is part of Indonesia, and part of the larger Maritime Southeast Asia region. Tectonically they are located on the Halmahera Plate within the Molucca Sea Collision Zone...
, Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, and eventually running to the Americas
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...
.
In addition to trading in goods, many nations began to trade in slavery
Slavery
Slavery is a system under which people are treated as property to be bought and sold, and are forced to work. Slaves can be held against their will from the time of their capture, purchase or birth, and deprived of the right to leave, to refuse to work, or to demand compensation...
. Trading in slaves was another way by which diseases were carried to new locations and peoples, for instance, from sub-Saharan Africa to the Caribbean and the Americas. During this time, different societies began to integrate, increasing the concentration of human
Human
Humans are the only living species in the Homo genus...
s and animal
Animal
Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...
s in certain places, which led to the emergence of new diseases as some jumped in mutation from animals to humans.
During this time sorcerers' and witch doctor
Witch doctor
A witch doctor originally referred to a type of healer who treated ailments believed to be caused by witchcraft. It is currently used to refer to healers in some third world regions, who use traditional healing rather than contemporary medicine...
s' treatment of disease was often focused on magic
Magic (paranormal)
Magic is the claimed art of manipulating aspects of reality either by supernatural means or through knowledge of occult laws unknown to science. It is in contrast to science, in that science does not accept anything not subject to either direct or indirect observation, and subject to logical...
and religion
Religion
Religion is a collection of cultural systems, belief systems, and worldviews that establishes symbols that relate humanity to spirituality and, sometimes, to moral values. Many religions have narratives, symbols, traditions and sacred histories that are intended to give meaning to life or to...
, and healing the entire body
Body
With regard to living things, a body is the physical body of an individual. "Body" often is used in connection with appearance, health issues and death...
and soul
Soul
A soul in certain spiritual, philosophical, and psychological traditions is the incorporeal essence of a person or living thing or object. Many philosophical and spiritual systems teach that humans have souls, and others teach that all living things and even inanimate objects have souls. The...
, rather than focusing on a few symptoms like modern medicine. Early medicine often included the use of herbs and meditation
Meditation
Meditation is any form of a family of practices in which practitioners train their minds or self-induce a mode of consciousness to realize some benefit....
. Based on archeological evidence, some prehistoric practitioners in both Europe and South America used trephining, making a hole in the skull to release illness. Severe diseases were often thought of as supernatural
Supernatural
The supernatural or is that which is not subject to the laws of nature, or more figuratively, that which is said to exist above and beyond nature...
or magical. The result of the introduction of Eurasian diseases to the Americas was that many more native peoples were killed by disease and germs
Microorganism
A microorganism or microbe is a microscopic organism that comprises either a single cell , cell clusters, or no cell at all...
than by the colonists' use of guns or other weapons. Scholars estimate that over a period of four centuries, epidemic diseases wiped out as much as 90 percent of the American indigenous populations.
In Europe during the age of exploration, diseases such as smallpox
Smallpox
Smallpox was an infectious disease unique to humans, caused by either of two virus variants, Variola major and Variola minor. The disease is also known by the Latin names Variola or Variola vera, which is a derivative of the Latin varius, meaning "spotted", or varus, meaning "pimple"...
, measles
Measles
Measles, also known as rubeola or morbilli, is an infection of the respiratory system caused by a virus, specifically a paramyxovirus of the genus Morbillivirus. Morbilliviruses, like other paramyxoviruses, are enveloped, single-stranded, negative-sense RNA viruses...
and tuberculosis
Tuberculosis
Tuberculosis, MTB, or TB is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs but can also affect other parts of the body...
(TB) had already been introduced centuries before through trade with Asia and Africa. People had developed some antibodies to these and other diseases from the Eurasian continent. When the Europeans traveled to new lands, they carried these diseases with them. (Note: Scholars believe TB was already endemic in the Americas.) When such diseases were introduced for the first time to new populations of humans, the effects on the native populations were widespread and deadly. The Columbian Exchange
Columbian Exchange
The Columbian Exchange was a dramatically widespread exchange of animals, plants, culture, human populations , communicable disease, and ideas between the Eastern and Western hemispheres . It was one of the most significant events concerning ecology, agriculture, and culture in all of human history...
, referring to Christopher Columbus
Christopher Columbus
Christopher Columbus was an explorer, colonizer, and navigator, born in the Republic of Genoa, in northwestern Italy. Under the auspices of the Catholic Monarchs of Spain, he completed four voyages across the Atlantic Ocean that led to general European awareness of the American continents in the...
's first contact with the native peoples of the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
, began the trade of animals, and plants, and unwittingly began an exchange of diseases.
It was not until the 1800s that humans began to recognize the existence and role of germs and microbes in relation to disease. Although many thinkers had ideas about germs, it was not until Louis Pasteur
Louis Pasteur
Louis Pasteur was a French chemist and microbiologist born in Dole. He is remembered for his remarkable breakthroughs in the causes and preventions of diseases. His discoveries reduced mortality from puerperal fever, and he created the first vaccine for rabies and anthrax. His experiments...
spread his theory about germs, and the need for washing hands and maintaining sanitation
Sanitation
Sanitation is the hygienic means of promoting health through prevention of human contact with the hazards of wastes. Hazards can be either physical, microbiological, biological or chemical agents of disease. Wastes that can cause health problems are human and animal feces, solid wastes, domestic...
(particularly in medical practice), that anyone listened. Many people were quite skeptical, but on May 22, 1881 Pasteur persuasively demonstrated the validity of his germ theory of disease with the first successful vaccination
Vaccination
Vaccination is the administration of antigenic material to stimulate the immune system of an individual to develop adaptive immunity to a disease. Vaccines can prevent or ameliorate the effects of infection by many pathogens...
. The anthrax
Anthrax
Anthrax is an acute disease caused by the bacterium Bacillus anthracis. Most forms of the disease are lethal, and it affects both humans and other animals...
vaccine was administered to 25 sheep while another 25 were used as a control. On May 31, 1881 all of the sheep were exposed to anthrax. While every sheep in the control group died, each of the vaccinated sheep survived. Pasteur’s experiment would become a milestone in disease prevention. His findings, in conjunction with other vaccines that followed, changed the way globalization affected the world.
Effects of globalization on disease in the modern world
Modern modes of transportation allow more people and products to travelTravel
Travel is the movement of people or objects between relatively distant geographical locations. 'Travel' can also include relatively short stays between successive movements.-Etymology:...
around the world at a faster pace; they also open the airways to the transcontinental movement of infectious disease vectors. One example is the West Nile Virus
West Nile virus
West Nile virus is a virus of the family Flaviviridae. Part of the Japanese encephalitis antigenic complex of viruses, it is found in both tropical and temperate regions. It mainly infects birds, but is known to infect humans, horses, dogs, cats, bats, chipmunks, skunks, squirrels, domestic...
. It is believed that this disease reached the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
via “mosquitoes that crossed the ocean by riding in airplane wheel wells and arrived in New York City in 1999.” With the use of air travel, people are able to go to foreign lands, contract a disease and not have any symptoms of illness until after they get home, and having exposed others to the disease along the way.
As medicine has progressed, many vaccines and cures have been developed for some of the worst diseases (plague, syphilis, typhus, cholera, malaria) which people suffer. But, because the evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
of disease organisms is very rapid, even with vaccines, there is difficulty providing full immunity
Immunity (medical)
Immunity is a biological term that describes a state of having sufficient biological defenses to avoid infection, disease, or other unwanted biological invasion. Immunity involves both specific and non-specific components. The non-specific components act either as barriers or as eliminators of wide...
to many diseases. Finding vaccines at all for some diseases remains extremely difficult. Without vaccines, the global world remains vulnerable to infectious diseases.
Evolution of disease presents a major threat in modern times. For example, the current "swine flu" or H1N1 virus is a new strain of an old form of flu, known for centuries as Asian flu based on its origin on that continent. From 1918-1920, a post-World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
global influenza epidemic killed an estimated 50-100 million people, including half a million in the United States alone. H1N1 is a virus that has evolved from and partially combined with portions of avian, swine, and human flu.
Globalization has increased the spread of infectious diseases from South to North, but also the risk of non-communicable diseases by transmission of culture and behavior from North to South. It is important to target and reduce the spread of infectious diseases in developing countries. However, addressing the risk factors of non-comunicable diseases and lifestyle risks in the South that cause disease, such as use or consumption of tobacco, alcohol, and unhealthy foods, is important as well.
Plague
Bubonic plagueBubonic plague
Plague is a deadly infectious disease that is caused by the enterobacteria Yersinia pestis, named after the French-Swiss bacteriologist Alexandre Yersin. Primarily carried by rodents and spread to humans via fleas, the disease is notorious throughout history, due to the unrivaled scale of death...
is a variant of the deadly flea
Flea
Flea is the common name for insects of the order Siphonaptera which are wingless insects with mouthparts adapted for piercing skin and sucking blood...
-borne disease plague
Yersinia pestis
Yersinia pestis is a Gram-negative rod-shaped bacterium. It is a facultative anaerobe that can infect humans and other animals....
, which is caused by the enterobacteria Yersinia pestis
Yersinia pestis
Yersinia pestis is a Gram-negative rod-shaped bacterium. It is a facultative anaerobe that can infect humans and other animals....
, that devastated human populations beginning in the 14th century. Bubonic plague is primarily spread by fleas that lived on the black rat
Black Rat
The black rat is a common long-tailed rodent of the genus Rattus in the subfamily Murinae . The species originated in tropical Asia and spread through the Near East in Roman times before reaching Europe by the 1st century and spreading with Europeans across the world.-Taxonomy:The black rat was...
, an animal that originated in south Asia and spread to Europe by the 6th century. It became common to cities and villages, traveling by ship with explorers. A human would become infected after being bitten by an infected flea. The first sign of an infection of bubonic plague is swelling of the lymph nodes, and the formation of buboes. These buboes would first appear in the groin or armpit area, and would often ooze pus
Pus
Pus is a viscous exudate, typically whitish-yellow, yellow, or yellow-brown, formed at the site of inflammatory during infection. An accumulation of pus in an enclosed tissue space is known as an abscess, whereas a visible collection of pus within or beneath the epidermis is known as a pustule or...
or blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
. Eventually infected individuals would become covered with dark splotches caused by bleeding under the skin. The symptoms would be accompanied by a high fever
Fever
Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...
, and within four to seven days of infection, more than half the victims would die. During the 14th and 15th century, humans did not know that a bacterium was the cause of plague, and efforts to slow the spread of disease were futile.
The first recorded outbreak of plague occurred in China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
in the 1330s, a time when China was engaged in substantial trade with western Asia and Europe. The plague reached Europe in October 1347. It was thought to have been brought into Europe through the port of Messina, Sicily
Sicily
Sicily is a region of Italy, and is the largest island in the Mediterranean Sea. Along with the surrounding minor islands, it constitutes an autonomous region of Italy, the Regione Autonoma Siciliana Sicily has a rich and unique culture, especially with regard to the arts, music, literature,...
, by a fleet of Genoese trading ships from Kaffa
Kaffa
Kaffa is the name of several geographical entities:*Kingdom of Kaffa, ancient Kingdom of the Sidamo people.*Kaffa, former province in Ethiopia.*Kaffa people, an ethnic group in Ethiopia....
, a seaport on the Crimean peninsula. When the ship left port in Kaffa, many of the inhabitants of the town were dying, and the crew was in a hurry to leave. By the time the fleet reached Messina, all the crew were either dead or dying; the rats that took passage with the ship slipped unnoticed to shore and carried the disease with them and their fleas.
Within Europe, the plague struck port cities first, then followed people along both sea and land trade routes. It raged through Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
into France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
and the British Isles
British Isles
The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...
. It was carried over the Alps
Alps
The Alps is one of the great mountain range systems of Europe, stretching from Austria and Slovenia in the east through Italy, Switzerland, Liechtenstein and Germany to France in the west....
into Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
, and eastward into Hungary
Hungary
Hungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The...
and Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
. For a time during the 14th and 15th centuries, the plague would recede. Every ten to twenty years, it would return. Later epidemics, however, were never as widespread as the earlier outbreaks, when nearly a third of the population died.
The plague has never died out. From 1896-1918 the plague swept through India, taking the lives of over 12.5 million people. Between 1906 and 1914, the Plague Research Commission was created, and published supplements to the Journal of Hygiene.
Measles
MeaslesMeasles
Measles, also known as rubeola or morbilli, is an infection of the respiratory system caused by a virus, specifically a paramyxovirus of the genus Morbillivirus. Morbilliviruses, like other paramyxoviruses, are enveloped, single-stranded, negative-sense RNA viruses...
is a highly contagious airborne virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
spread by contact with infected oral and nasal fluids. When a person with measles coughs or sneezes, he releases microscopic particles into the air. During the 4-12 day incubation period
Incubation period
Incubation period is the time elapsed between exposure to a pathogenic organism, a chemical or radiation, and when symptoms and signs are first apparent...
, an infected individual shows no symptoms, but as the disease progresses, the following symptoms appear: runny nose, cough, red eyes, extremely high fever and a rash.
Measles is an endemic disease, meaning that it has been continually present in a community, and many people develop resistance. In populations that have not been exposed to measles, exposure to the new disease can be devastating. In 1529, a measles outbreak in Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
killed two-thirds of the natives who had previously survived smallpox. Two years later measles was responsible for the deaths of half the indigenous population of Honduras
Honduras
Honduras is a republic in Central America. It was previously known as Spanish Honduras to differentiate it from British Honduras, which became the modern-day state of Belize...
, and ravaged Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
, Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
, and the Inca civilization.
Historically, measles was very prevalent throughout the world, as it is highly contagious. According to the National Immunization Program, 90% of people were infected with measles by age 15, acquiring immunity to further outbreaks. Until a vaccine was developed in 1963, measles was considered to be deadlier than smallpox. Vaccination reduced the number of reported occurrences by 98%. Major epidemics have predominantly occurred in unvaccinated populations, particularly among nonwhite Hispanic
Hispanic
Hispanic is a term that originally denoted a relationship to Hispania, which is to say the Iberian Peninsula: Andorra, Gibraltar, Portugal and Spain. During the Modern Era, Hispanic sometimes takes on a more limited meaning, particularly in the United States, where the term means a person of ...
and African American
African American
African Americans are citizens or residents of the United States who have at least partial ancestry from any of the native populations of Sub-Saharan Africa and are the direct descendants of enslaved Africans within the boundaries of the present United States...
children under 5 years old. In 2000 a group of experts determined that measles was no longer epidemic in the United States. The majority of cases that occur are among immigrants from other countries.
Typhus
Typhus is caused by rickettsiaRickettsia
Rickettsia is a genus of non-motile, Gram-negative, non-sporeforming, highly pleomorphic bacteria that can present as cocci , rods or thread-like . Being obligate intracellular parasites, the Rickettsia survival depends on entry, growth, and replication within the cytoplasm of eukaryotic host cells...
, which is transmitted to humans through lice. The main vector for typhus
Typhus
Epidemic typhus is a form of typhus so named because the disease often causes epidemics following wars and natural disasters...
is the rat flea
Rat flea
The Oriental rat flea , also known as the tropical rat flea, is a parasite of rodents, primarily of the genus Rattus, and is a primary vector for bubonic plague and murine typhus. This occurs when the flea has fed on an infected rodent, and then bites a human...
. Flea bites and infected flea feces in the respiratory tract are the two most common methods of transmission. In areas where rats are not common, typhus may also be transmitted through cat
Cat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
and opossum fleas. The incubation period
Incubation period
Incubation period is the time elapsed between exposure to a pathogenic organism, a chemical or radiation, and when symptoms and signs are first apparent...
of typhus is 7–14 days. The symptoms start with a fever
Fever
Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...
, then headache, rash
Rash
A rash is a change of the skin which affects its color, appearance or texture. A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, cracked or blistered, swell and may be painful. The causes, and...
, and eventually stupor
Stupor
Stupor is the lack of critical cognitive function and level of consciousness wherein a sufferer is almost entirely unresponsive and only responds to base stimuli such as pain. This is often mistaken for delirium and treated with Haldol and or other anti-psychotic drugs...
. Spontaneous recovery occurs in 80-90% of victims.
The first outbreak of typhus was recorded in 1489. Historians believe that troops from the Balkans
Balkans
The Balkans is a geopolitical and cultural region of southeastern Europe...
, hired by the Spanish army, brought it to Spain with them. By 1490 typhus traveled from the eastern Mediterranean into Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
and Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
, and by 1494, it had swept across Europe. From 1500-1914, more soldiers were killed by typhus than from all the combined military
Military
A military is an organization authorized by its greater society to use lethal force, usually including use of weapons, in defending its country by combating actual or perceived threats. The military may have additional functions of use to its greater society, such as advancing a political agenda e.g...
actions during that time. It was a disease associated with the crowded conditions of urban poverty and refugees as well. Finally, during World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
, governments instituted preventative delousing measures among the armed forces and other groups, and the disease began to decline. The creation of antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
s has allowed disease to be controlled within two days of taking a 200 mg dose of tetracycline.
Syphilis
Syphilis is a sexually transmitted diseaseSexually transmitted disease
Sexually transmitted disease , also known as a sexually transmitted infection or venereal disease , is an illness that has a significant probability of transmission between humans by means of human sexual behavior, including vaginal intercourse, oral sex, and anal sex...
that causes open sores, delirium
Delirium
Delirium or acute confusional state is a common and severe neuropsychiatric syndrome with core features of acute onset and fluctuating course, attentional deficits and generalized severe disorganization of behavior...
and rotting skin, and is characterized by genital ulcer
Genital ulcer
A Genital ulcer is an ulcer located on the genital area, usually caused by a sexually transmitted disease such as genital herpes, syphilis, chancroid, or thrush. Some other signs of having genital ulcers include enlarged lymph nodes in the groin area, or vesicular lesions, which are small, elevated...
s. Syphilis can also do damage to the nervous system, brain and heart. The disease can be transmitted from mother to child.
The origins of syphilis
Syphilis
Syphilis is a sexually transmitted infection caused by the spirochete bacterium Treponema pallidum subspecies pallidum. The primary route of transmission is through sexual contact; however, it may also be transmitted from mother to fetus during pregnancy or at birth, resulting in congenital syphilis...
are unknown, and some historians argue that it descended from a twenty-thousand-year-old African zoonosis
Zoonosis
A zoonosis or zoonoseis any infectious disease that can be transmitted from non-human animals to humans or from humans to non-human animals . In a study of 1415 pathogens known to affect humans, 61% were zoonotic...
. Other historians place its emergence in the New World
New World
The New World is one of the names used for the Western Hemisphere, specifically America and sometimes Oceania . The term originated in the late 15th century, when America had been recently discovered by European explorers, expanding the geographical horizon of the people of the European middle...
, arguing that the crews of Columbus’s ships first brought the disease to Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
. The first recorded case of syphilis occurred in Naples
Naples
Naples is a city in Southern Italy, situated on the country's west coast by the Gulf of Naples. Lying between two notable volcanic regions, Mount Vesuvius and the Phlegraean Fields, it is the capital of the region of Campania and of the province of Naples...
in 1495, after King Charles VIII
Charles VIII of France
Charles VIII, called the Affable, , was King of France from 1483 to his death in 1498. Charles was a member of the House of Valois...
of France besieged the city of Naples, Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
. The soldiers, and the prostitutes who followed their camps, came from all corners of Europe. When they went home, they took the disease with them and spread it across the continent.
Smallpox
SmallpoxSmallpox
Smallpox was an infectious disease unique to humans, caused by either of two virus variants, Variola major and Variola minor. The disease is also known by the Latin names Variola or Variola vera, which is a derivative of the Latin varius, meaning "spotted", or varus, meaning "pimple"...
is a highly contagious disease caused by the Variola virus. There are four variations of smallpox; variola major, variola minor, haemorrhagic, and malignant, with the most common being variola major and variola minor. Symptoms of the disease including hemorrhaging, blindness
Blindness
Blindness is the condition of lacking visual perception due to physiological or neurological factors.Various scales have been developed to describe the extent of vision loss and define blindness...
, back ache, vomiting
Vomiting
Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...
, which generally occur shortly after the 12-17 day incubation period. The virus begins to attack skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
cells, and eventually leads to an eruption of pimples that cover the whole body. As the disease progresses, the pimples fill up with pus or merge together. This merging results in a sheet that can detach the bottom layer from the top layer of skin. The disease is easily transmitted through airborne pathways (coughing, sneezing, and breathing), as well as through contaminated bedding, clothing or other fabrics,
It is believed that smallpox first emerged over 3000 years ago, probably in India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
or Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...
. There have been numerous recorded devastating epidemic
Epidemic
In epidemiology, an epidemic , occurs when new cases of a certain disease, in a given human population, and during a given period, substantially exceed what is expected based on recent experience...
s throughout the world, with high losses of life.
Smallpox was a common disease in Eurasia in the 15th century, and was spread by explorers
Exploration
Exploration is the act of searching or traveling around a terrain for the purpose of discovery of resources or information. Exploration occurs in all non-sessile animal species, including humans...
and invaders. After Columbus landed on the island of Hispaniola
Hispaniola
Hispaniola is a major island in the Caribbean, containing the two sovereign states of the Dominican Republic and Haiti. The island is located between the islands of Cuba to the west and Puerto Rico to the east, within the hurricane belt...
during his second voyage in 1493, local people started to die of a virulent infection
Infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
. Before the smallpox epidemic started, more than one million indigenous people had lived on the island
Island
An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...
; afterward, only ten thousand had survived.
During the 16th century, Spanish soldiers introduced smallpox by contact with natives of the Aztec
Aztec
The Aztec people were certain ethnic groups of central Mexico, particularly those groups who spoke the Nahuatl language and who dominated large parts of Mesoamerica in the 14th, 15th and 16th centuries, a period referred to as the late post-classic period in Mesoamerican chronology.Aztec is the...
capital Tenochtitlan. A devastating epidemic broke out among the indigenous people, killing thousands.
In 1617, smallpox reached Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
, probably brought by earlier explorers to Nova Scotia
Nova Scotia
Nova Scotia is one of Canada's three Maritime provinces and is the most populous province in Atlantic Canada. The name of the province is Latin for "New Scotland," but "Nova Scotia" is the recognized, English-language name of the province. The provincial capital is Halifax. Nova Scotia is the...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
.” By 1638 the disease had broken out among people in Boston, Massachusetts. In 1721 people fled the city after an outbreak, but the residents spread the disease to others throughout the thirteen colonies
Thirteen Colonies
The Thirteen Colonies were English and later British colonies established on the Atlantic coast of North America between 1607 and 1733. They declared their independence in the American Revolution and formed the United States of America...
. Smallpox broke out in six separate epidemics in the United States through 1968.
The smallpox vaccine
Smallpox vaccine
The smallpox vaccine was the first successful vaccine to be developed. The process of vaccination was discovered by Edward Jenner in 1796, who acted upon his observation that milkmaids who caught the cowpox virus did not catch smallpox...
was developed in 1798 by Edward Jenner
Edward Jenner
Edward Anthony Jenner was an English scientist who studied his natural surroundings in Berkeley, Gloucestershire...
. By 1979 the disease had been completely eradicated
Eradication of infectious diseases
Eradication is the reduction of an infectious disease's prevalence in the global host population to zero. It is sometimes confused with elimination, which describes either the reduction of an infectious disease's prevalence in a regional population to zero, or the reduction of the global prevalence...
, with no new outbreaks. The WHO
Who
Who may refer to:* Who , an English-language pronoun* who , a Unix command* Who?, one of the Five Ws in journalism- Art and entertainment :* Who? , a 1958 novel by Algis Budrys...
stopped providing vaccinations and by 1986, vaccination was no longer necessary to anyone in the world except in the event of future outbreak. Currently the smallpox virus exists only in laboratories (25).
Leprosy
LeprosyLeprosy
Leprosy or Hansen's disease is a chronic disease caused by the bacteria Mycobacterium leprae and Mycobacterium lepromatosis. Named after physician Gerhard Armauer Hansen, leprosy is primarily a granulomatous disease of the peripheral nerves and mucosa of the upper respiratory tract; skin lesions...
, also known as Hansen’s Disease, is caused by a bacillus
Bacillus
Bacillus is a genus of Gram-positive, rod-shaped bacteria and a member of the division Firmicutes. Bacillus species can be obligate aerobes or facultative anaerobes, and test positive for the enzyme catalase. Ubiquitous in nature, Bacillus includes both free-living and pathogenic species...
, Mycobacterium leprae
Mycobacterium leprae
Mycobacterium leprae, also known as Hansen’s coccus spirilly, mostly found in warm tropical countries, is a bacterium that causes leprosy . It is an intracellular, pleomorphic, acid-fast bacterium. M. leprae is an aerobic bacillus surrounded by the characteristic waxy coating unique to mycobacteria...
. It is a chronic disease with an incubation period of up to five years. Symptoms often include irritation or erosion of the skin, and affects on the peripheral nerves, mucosa of the upper respiratory tract and eyes. The most common sign of leprosy are pale reddish spots on the skin that lack sensation.
Leprosy probably originated in India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, more than four thousand years ago. It was prevalent in ancient societies in China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, Egypt and India, and was transmitted throughout the world by various traveling groups, including Roman Legion
Roman legion
A Roman legion normally indicates the basic ancient Roman army unit recruited specifically from Roman citizens. The organization of legions varied greatly over time but they were typically composed of perhaps 5,000 soldiers, divided into maniples and later into "cohorts"...
naires, Crusaders
Crusaders
The Crusaders are a New Zealand professional rugby union team based in Christchurch that competes in the Super Rugby competition. They are the most successful team in Super Rugby history with seven titles...
, Spanish conquistador
Conquistador
Conquistadors were Spanish soldiers, explorers, and adventurers who brought much of the Americas under the control of Spain in the 15th to 16th centuries, following Europe's discovery of the New World by Christopher Columbus in 1492...
s, Asian seafarers, European colonists, and Arab, African, and American slave traders. Some historians believe that Alexander the Great's troops brought leprosy from India to Europe during the 3rd century BC. With the help of the crusaders and other travelers, leprosy reached epidemic
Epidemic
In epidemiology, an epidemic , occurs when new cases of a certain disease, in a given human population, and during a given period, substantially exceed what is expected based on recent experience...
proportions by the 13th century.
Once detected, leprosy can be cured using multi-drug therapy (MDT), composed of two or three antibiotics, depending on the type of leprosy. In 1991 the World Health Assembly began an attempt to eliminate leprosy. By 2005 116 of 122 countries were reported to be free of leprosy.
Malaria
On Nov. 6, 1880 Alphonse Laveran discovered that malariaMalaria
Malaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists of the genus Plasmodium. The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases...
(then called "Marsh Fever") was a protozoan parasite, and that mosquitoes carry and transmit malaria. Malaria is a protozoan infectious disease
Infectious disease
Infectious diseases, also known as communicable diseases, contagious diseases or transmissible diseases comprise clinically evident illness resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism...
that is generally transmitted to humans by mosquitoes between dusk and dawn. The European variety, known as "vivax" after the Plasmodium vivax
Plasmodium vivax
Plasmodium vivax is a protozoal parasite and a human pathogen. The most frequent and widely distributed cause of recurring malaria, P. vivax is one of the four species of malarial parasite that commonly infect humans. It is less virulent than Plasmodium falciparum, which is the deadliest of the...
parasite, causes a relatively mild, yet chronically aggravating disease. The west African variety is caused by the sporozoan parasite, Plasmodium falciparum
Plasmodium falciparum
Plasmodium falciparum is a protozoan parasite, one of the species of Plasmodium that cause malaria in humans. It is transmitted by the female Anopheles mosquito. Malaria caused by this species is the most dangerous form of malaria, with the highest rates of complications and mortality...
, and results in a severely debilitating and deadly disease.
In 1492, malaria
Malaria
Malaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists of the genus Plasmodium. The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases...
was a disease endemic
Endemic (epidemiology)
In epidemiology, an infection is said to be endemic in a population when that infection is maintained in the population without the need for external inputs. For example, chickenpox is endemic in the UK, but malaria is not...
to Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
and Western Africa. The variety from West Africa, Plasmodium falciparum, became a threat to colonists and indigenous people alike when it was introduced into the Americas through Africans transported in the slave trade. It is now endemic to tropical areas.
Parts of the Third World
Third World
The term Third World arose during the Cold War to define countries that remained non-aligned with either capitalism and NATO , or communism and the Soviet Union...
are more affected by malaria than the rest of the world. For instance, many inhabitants of sub-Saharan Africa are affected by recurring attacks of malaria throughout their lives. In many areas of Africa, there is limited running water
Running Water
Running Water may be:* Running Water, Tennessee, former name of Whiteside, Tennessee* Running Water, South Dakota, a community in Bon Homme County, South Dakota* "Running Water" from the 1983 album The Present...
. The residents' use of wells and cistern
Cistern
A cistern is a waterproof receptacle for holding liquids, usually water. Cisterns are often built to catch and store rainwater. Cisterns are distinguished from wells by their waterproof linings...
s provides many sites for the breeding of mosquitoes and spread of the disease. Mosquitoes use areas of standing water like marshes, wetlands, and water drums to breed.
Tuberculosis
The bacterium that causes tuberculosisTuberculosis
Tuberculosis, MTB, or TB is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs but can also affect other parts of the body...
, Mycobacterium tuberculosis
Mycobacterium tuberculosis
Mycobacterium tuberculosis is a pathogenic bacterial species in the genus Mycobacterium and the causative agent of most cases of tuberculosis . First discovered in 1882 by Robert Koch, M...
, is generally spread when an infected person cough
Cough
A cough is a sudden and often repetitively occurring reflex which helps to clear the large breathing passages from secretions, irritants, foreign particles and microbes...
s and another person inhales the bacteria. Once inhaled TB frequently grows in the lungs, but can spread to any part of the body. Although TB is highly contagious, in most cases the human body is able to fend off the bacteria. But, TB can remain dormant
Dormant
Dormant means lacking activity. It can refer to:*Dormancy in an organism's life cycle*Dormant volcano, a volcano that is inactive but may become active in the future...
in the body for years, and become active unexpectedly. If and when the disease does become active in the body, it can multiply rapidly, causing the person to develop many symptoms including cough (sometimes with blood), night sweats, fever, chest pains, loss of appetite and loss of weight. This disease can occur in both adults and children and is especially common among those with weak or undeveloped immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
s.
Tuberculosis (TB) has been one of history’s greatest killers, taking the lives of over 3 million people annually. It has been called the "white plague". According to the WHO, approximately fifty percent of people infected with TB today live in Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
. It is the most prevalent, life-threatening infection among AIDS
AIDS
Acquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the human immunodeficiency virus...
patients. It has increased in areas where HIV seroprevalence
Seroprevalence
Seroprevalence is the number of persons in a population who test positive for a specific disease based on serology specimens; often presented as a percent of the total specimens tested or as a proportion per 100,000 persons tested...
is high.
Air travel
Air travel
Air travel is a form of travel in vehicles such as airplanes, helicopters, hot air balloons, blimps, gliders, hang gliding, parachuting or anything else that can sustain flight.-Domestic and international flights:...
and the other methods of travel which have made global interaction easier, have increased the spread of TB across different societies. Luckily, the BCG vaccine
Bacillus Calmette-Guérin
Bacillus Calmette-Guérin is a vaccine against tuberculosis that is prepared from a strain of the attenuated live bovine tuberculosis bacillus, Mycobacterium bovis, that has lost its virulence in humans by being specially subcultured in an artificial medium for 13 years, and also prepared from...
was developed, which prevents TB meningitis and miliary TB in childhood. But, the vaccine does not provide substantial protection against the more virulent forms of TB found among adults. Most forms of TB can be treated with antibiotics to kill the bacteria. The two antibiotics most commonly used are rifampicin
Rifampicin
Rifampicin or rifampin is a bactericidal antibiotic drug of the rifamycin group. It is a semisynthetic compound derived from Amycolatopsis rifamycinica ...
and isoniazid
Isoniazid
Isoniazid , also known as isonicotinylhydrazine , is an organic compound that is the first-line antituberculosis medication in prevention and treatment. It was first discovered in 1912, and later in 1951 it was found to be effective against tuberculosis by inhibiting its mycolic acid...
. There are dangers, however, of a rise of antibiotic-resistant TB. The TB treatment regimen is lengthy, and difficult for poor and disorganized people to complete, increasing resistance of bacteria.
HIV/AIDS
AIDS/HIV is among the newest and deadliest diseases. According to the World Health OrganizationWorld Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
, it is unknown where the HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
originated, but it appeared to move from animals to humans. It may have been isolated within many groups throughout the world. It is believed that HIV arose from another, less harmful virus, that mutated and became more virulent. The first two AIDS/HIV cases were detected in 1981. As of 2004, an estimated 1,039,000 to 1,185,000 persons in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
were living with HIV/AIDS, and an estimated 39.5 million people worldwide are living with HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
”. The WHO also reports that there has been a 50% increase in HIV-infected people since 2004. Despite efforts in numerous countries, awareness and prevention programs have not been effective enough to reduce the numbers of new HIV cases in many parts of the world, where it is associated with high mobility of men, poverty and sexual mores among certain populations. Uganda has had an effective program, however. Until recently, the South African government refused to mount strong preventive or education programs. Prevention programs are difficult to maintain and, as a result, the protective measures usually do not last long after the program stops.
Non-communicable disease
GlobalizationGlobalization
Globalization refers to the increasingly global relationships of culture, people and economic activity. Most often, it refers to economics: the global distribution of the production of goods and services, through reduction of barriers to international trade such as tariffs, export fees, and import...
can also benefit people with non-communicable diseases such as heart problems or mental health problems. Global trade and rules set forth by the World Trade Organization
World Trade Organization
The World Trade Organization is an organization that intends to supervise and liberalize international trade. The organization officially commenced on January 1, 1995 under the Marrakech Agreement, replacing the General Agreement on Tariffs and Trade , which commenced in 1948...
can actually benefit the health of people by making their incomes higher, allowing them to afford better health care. Also the national income of a country, mostly obtained by trading on the global market, is important because it dictates how much a government spends on health care for its citizens. Although poorer countries have not yet experienced this and are still suffering from diseases listed above.
See also
- Chagas diseaseChagas diseaseChagas disease is a tropical parasitic disease caused by the flagellate protozoan Trypanosoma cruzi. T. cruzi is commonly transmitted to humans and other mammals by an insect vector, the blood-sucking insects of the subfamily Triatominae most commonly species belonging to the Triatoma, Rhodnius,...
- Eradication of infectious diseasesEradication of infectious diseasesEradication is the reduction of an infectious disease's prevalence in the global host population to zero. It is sometimes confused with elimination, which describes either the reduction of an infectious disease's prevalence in a regional population to zero, or the reduction of the global prevalence...
- Infectious diseaseInfectious diseaseInfectious diseases, also known as communicable diseases, contagious diseases or transmissible diseases comprise clinically evident illness resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism...
- GlobalizationGlobalizationGlobalization refers to the increasingly global relationships of culture, people and economic activity. Most often, it refers to economics: the global distribution of the production of goods and services, through reduction of barriers to international trade such as tariffs, export fees, and import...
- List of epidemics
- PandemicPandemicA pandemic is an epidemic of infectious disease that is spreading through human populations across a large region; for instance multiple continents, or even worldwide. A widespread endemic disease that is stable in terms of how many people are getting sick from it is not a pandemic...
- Transmission (medicine)Transmission (medicine)In medicine and biology, transmission is the passing of a communicable disease from an infected host individual or group to a conspecific individual or group, regardless of whether the other individual was previously infected...
- Tropical diseaseTropical diseaseTropical diseases are diseases that are prevalent in or unique to tropical and subtropical regions. The diseases are less prevalent in temperate climates, due in part to the occurrence of a cold season, which controls the insect population by forcing hibernation. Insects such as mosquitoes and...