Cowpox
Encyclopedia
Cowpox is a skin disease caused by a virus
known as the Cowpox virus. The pox
is related to the vaccinia
virus and got its name from the distribution of the disease when dairymaids touched the udder
s of infected cows. The ailment manifests itself in the form of red blister
s and is transmitted by touch from infected animals to human
s. Cowpox is similar to but much milder than the highly contagious and sometimes deadly smallpox disease. It resembles mild smallpox, and was the basis of the first smallpox vaccines. When the patient recovers from cowpox, the person is immune to smallpox
.
The cowpox virus was used to perform the first successful vaccination
against a disease, smallpox, which is caused by the related Variola virus. Therefore, the word "vaccination" — first used by Edward Jenner
(an English physician) in 1796 — has the Latin
root vaccinus meaning of or from cows. World Health Organization
in 1980 announced that smallpox was the first disease that had been eradicated world wide by a program of vaccination. Despite the eradication of smallpox in the past century, other orthopoxviruses, such as monkeypox virus, vaccinia virus in Brazil, and cowpox virus (CPXV) in Europe, still infect humans. CPXV has been restricted to the Old World with wild rodents as its natural reservoir. Human CPXV infections are commonly described in relation to contact with diseased domestic cats, sometimes directly from rats or domesticated house mice. Human infections usually remain localized and self-limiting but can become fatal in immunosuppressed patients.
, in Dorset
, in 1774 and the German teacher Peter Plett in 1791. Jesty inoculated his wife and two young sons and thus spared them probable death by smallpox which was raging in the area in which they lived. His patients who had contracted and recovered from the similar but milder cowpox (mainly milkmaids), seemed to be immune not only to further cases of cowpox, but also to smallpox. By scratching the fluid from cowpox lesions into the skin of healthy individuals, he was able to immunize those people against smallpox. It was reported that farmers and people working regularly with cows and horses were often spared during smallpox outbreaks. More and more an investigation conducted towards 1790 by the British Army
showed that horse-mounted troops
were less infected by smallpox than infantry
, and this due to a major exposure to the similar horse pox virus (Variola equina). By the early 19th century, more than 100,000 persons in Great Britain had been vaccinated. The arm-to-arm method was also used to distribute Jenner's vaccine throughout the Spanish Empire. Spanish king Charles IV's daughter had been stricken with smallpox in 1798, and after she recovered, he arranged for the rest of his family to be vaccinated. In 1803, the king, convinced of the benefits of the vaccine, ordered his personal physician Francis Xavier de Balmis, to deliver it to the Spanish dominions in North and South America. To maintain the vaccine in an available state during the voyage, the physician recruited from the orphanages of Spain twenty-two young boys, age three to nine years, who have never had cowpox or smallpox before. During the trip across the Atlantic, de Balmis vaccinated the orphans in a living chain. Two children were vaccinated immediately before departure, and when cowpox pustules had appeared on their arms, material from these lesions was used to vaccinate two more children.
Jesty did not publicise his findings, however, credit was assumed by Dr. Jenner who performed his first inoculation, twenty-two years later and publicised his findings. It is said that Jenner made this discovery by himself possibly with out knowing previous accounts twenty years earlier. Although Jesty could have been the first to discover it, Jenner let everyone know and understand it, thus taking credit for it.
The virus is found in Europe
, and mainly in the UK. Human cases today are very rare and most often contracted from domestic cat
s. The virus is not commonly found in cows; the reservoir hosts for the virus are woodland
rodent
s, particularly vole
s. It is from these rodents that domestic cats contract the virus. Symptoms in cats include lesion
s on the face, neck, forelimbs, and paws, and less commonly upper respiratory tract infection
. Symptoms of infection with cowpox virus in humans are localized, pustular lesions generally found on the hands and limited to the site of introduction. The incubation period
is nine to ten days. The virus is prevalent in late summer and autumn.
used in early 19th century America. Popularized by Jenner in the late 1790s, kinepox was a far safer method for inoculating people against smallpox than the previous method, variolation, which had a 3% fatality rate.
In a famous letter to Meriwether Lewis
in 1803, Thomas Jefferson
instructed the Lewis and Clark expedition
to "carry with you some matter of the kine-pox; inform those of them with whom you may be, of its efficacy as a preservative from the smallpox; & encourage them in the use of it..." Jefferson had developed an interest in protecting Native American
s from smallpox having been aware of epidemic
s along the Missouri River
during the previous century. One year prior to his special instructions to Lewis, Jefferson had persuaded a visiting delegation
of North American Indian Chieftains to be vaccinated with kinepox during the winter of 1801-2. Unfortunately, Lewis never got the opportunity to use kinepox during the pair's expedition as it had become inadvertently inactive — a common occurrence in a time before vaccines were stabilized with preservatives like glycerol
or kept at refrigeration temperatures.
Cowpox was the original vaccine of sorts for smallpox. After infection with the disease, the body (usually) gains the ability of recognizing the similar smallpox virus from its antigen
s and so is able to fight the smallpox disease much more efficiently. The vaccinia virus now used for smallpox vaccination is sufficiently different from the cowpox virus found in the wild as to be considered a separate virus.
The virus contains one hundred and eighty-six thousand base pairs of DNA, which contains the information for about one hundred and eighty-seven genes. This makes smallpox one of the most complicated viruses known. Some one hundred of these genes give instructions for key parts of the human immune system, giving a clue as to why smallpox is so lethal.
, prevention against cowpox is by vaccination against smallpox.
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...
known as the Cowpox virus. The pox
Pox
A pox is a type of disease, often caused by an animal virus, characterised by pockmarks. The term may be used to refer to disease.Pox, as a disease, may refer to:*Poxviruses...
is related to the vaccinia
Vaccinia
Vaccinia virus is a large, complex, enveloped virus belonging to the poxvirus family. It has a linear, double-stranded DNA genome approximately 190 kbp in length, and which encodes for approximately 250 genes. The dimensions of the virion are roughly 360 × 270 × 250 nm, with a mass of...
virus and got its name from the distribution of the disease when dairymaids touched the udder
Udder
An udder is an organ formed of the mammary glands of female quadruped mammals, especially ruminants such as cattle, goats, sheep and deer. The udder is a single mass hanging beneath the animal, consisting of pairs of mammary glands...
s of infected cows. The ailment manifests itself in the form of red blister
Blister
A blister is a small pocket of fluid within the upper layers of the skin, typically caused by forceful rubbing , burning, freezing, chemical exposure or infection. Most blisters are filled with a clear fluid called serum or plasma...
s and is transmitted by touch from infected animals to human
Human
Humans are the only living species in the Homo genus...
s. Cowpox is similar to but much milder than the highly contagious and sometimes deadly smallpox disease. It resembles mild smallpox, and was the basis of the first smallpox vaccines. When the patient recovers from cowpox, the person is immune to 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"...
.
The cowpox virus was used to perform 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...
against a disease, smallpox, which is caused by the related Variola virus. Therefore, the word "vaccination" — first used by Edward Jenner
Edward Jenner
Edward Anthony Jenner was an English scientist who studied his natural surroundings in Berkeley, Gloucestershire...
(an English physician) in 1796 — has the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
root vaccinus meaning of or from cows. World Health Organization
World 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...
in 1980 announced that smallpox was the first disease that had been eradicated world wide by a program of vaccination. Despite the eradication of smallpox in the past century, other orthopoxviruses, such as monkeypox virus, vaccinia virus in Brazil, and cowpox virus (CPXV) in Europe, still infect humans. CPXV has been restricted to the Old World with wild rodents as its natural reservoir. Human CPXV infections are commonly described in relation to contact with diseased domestic cats, sometimes directly from rats or domesticated house mice. Human infections usually remain localized and self-limiting but can become fatal in immunosuppressed patients.
Origin
In the years 1770 till 1790 at least six people who had contact with a cow had tested independently the possibility of using the cowpox vaccine as an immunization for smallpox in humans for the first time; among them the English farmer Benjamin JestyBenjamin Jesty
Benjamin Jesty was a farmer at Yetminster in Dorset, England, notable for his early experiment in inducing immunity against smallpox using cowpox....
, in Dorset
Dorset
Dorset , is a county in South West England on the English Channel coast. The county town is Dorchester which is situated in the south. The Hampshire towns of Bournemouth and Christchurch joined the county with the reorganisation of local government in 1974...
, in 1774 and the German teacher Peter Plett in 1791. Jesty inoculated his wife and two young sons and thus spared them probable death by smallpox which was raging in the area in which they lived. His patients who had contracted and recovered from the similar but milder cowpox (mainly milkmaids), seemed to be immune not only to further cases of cowpox, but also to smallpox. By scratching the fluid from cowpox lesions into the skin of healthy individuals, he was able to immunize those people against smallpox. It was reported that farmers and people working regularly with cows and horses were often spared during smallpox outbreaks. More and more an investigation conducted towards 1790 by the British Army
British Army
The British Army is the land warfare branch of Her Majesty's Armed Forces in the United Kingdom. It came into being with the unification of the Kingdom of England and Scotland into the Kingdom of Great Britain in 1707. The new British Army incorporated Regiments that had already existed in England...
showed that horse-mounted troops
Cavalry
Cavalry or horsemen were soldiers or warriors who fought mounted on horseback. Cavalry were historically the third oldest and the most mobile of the combat arms...
were less infected by smallpox than infantry
Infantry
Infantrymen are soldiers who are specifically trained for the role of fighting on foot to engage the enemy face to face and have historically borne the brunt of the casualties of combat in wars. As the oldest branch of combat arms, they are the backbone of armies...
, and this due to a major exposure to the similar horse pox virus (Variola equina). By the early 19th century, more than 100,000 persons in Great Britain had been vaccinated. The arm-to-arm method was also used to distribute Jenner's vaccine throughout the Spanish Empire. Spanish king Charles IV's daughter had been stricken with smallpox in 1798, and after she recovered, he arranged for the rest of his family to be vaccinated. In 1803, the king, convinced of the benefits of the vaccine, ordered his personal physician Francis Xavier de Balmis, to deliver it to the Spanish dominions in North and South America. To maintain the vaccine in an available state during the voyage, the physician recruited from the orphanages of Spain twenty-two young boys, age three to nine years, who have never had cowpox or smallpox before. During the trip across the Atlantic, de Balmis vaccinated the orphans in a living chain. Two children were vaccinated immediately before departure, and when cowpox pustules had appeared on their arms, material from these lesions was used to vaccinate two more children.
Jesty did not publicise his findings, however, credit was assumed by Dr. Jenner who performed his first inoculation, twenty-two years later and publicised his findings. It is said that Jenner made this discovery by himself possibly with out knowing previous accounts twenty years earlier. Although Jesty could have been the first to discover it, Jenner let everyone know and understand it, thus taking credit for it.
The virus is found in 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 mainly in the UK. Human cases today are very rare and most often contracted from domestic 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...
s. The virus is not commonly found in cows; the reservoir hosts for the virus are woodland
Woodland
Ecologically, a woodland is a low-density forest forming open habitats with plenty of sunlight and limited shade. Woodlands may support an understory of shrubs and herbaceous plants including grasses. Woodland may form a transition to shrubland under drier conditions or during early stages of...
rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
s, particularly vole
Vole
A vole is a small rodent resembling a mouse but with a stouter body, a shorter hairy tail, a slightly rounder head, smaller ears and eyes, and differently formed molars . There are approximately 155 species of voles. They are sometimes known as meadow mice or field mice in North America...
s. It is from these rodents that domestic cats contract the virus. Symptoms in cats include lesion
Lesion
A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...
s on the face, neck, forelimbs, and paws, and less commonly upper respiratory tract infection
Respiratory tract infection
Respiratory tract infection refers to any of a number of infectious diseases involving the respiratory tract. An infection of this type is normally further classified as an upper respiratory tract infection or a lower respiratory tract infection...
. Symptoms of infection with cowpox virus in humans are localized, pustular lesions generally found on the hands and limited to the site of introduction. 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...
is nine to ten days. The virus is prevalent in late summer and autumn.
Kinepox
Kinepox is an alternate term for the smallpox vaccineSmallpox 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...
used in early 19th century America. Popularized by Jenner in the late 1790s, kinepox was a far safer method for inoculating people against smallpox than the previous method, variolation, which had a 3% fatality rate.
In a famous letter to Meriwether Lewis
Meriwether Lewis
Meriwether Lewis was an American explorer, soldier, and public administrator, best known for his role as the leader of the Lewis and Clark Expedition also known as the Corps of Discovery, with William Clark...
in 1803, Thomas Jefferson
Thomas Jefferson
Thomas Jefferson was the principal author of the United States Declaration of Independence and the Statute of Virginia for Religious Freedom , the third President of the United States and founder of the University of Virginia...
instructed the Lewis and Clark expedition
Lewis and Clark Expedition
The Lewis and Clark Expedition, or ″Corps of Discovery Expedition" was the first transcontinental expedition to the Pacific Coast by the United States. Commissioned by President Thomas Jefferson and led by two Virginia-born veterans of Indian wars in the Ohio Valley, Meriwether Lewis and William...
to "carry with you some matter of the kine-pox; inform those of them with whom you may be, of its efficacy as a preservative from the smallpox; & encourage them in the use of it..." Jefferson had developed an interest in protecting Native American
Indigenous peoples of the Americas
The indigenous peoples of the Americas are the pre-Columbian inhabitants of North and South America, their descendants and other ethnic groups who are identified with those peoples. Indigenous peoples are known in Canada as Aboriginal peoples, and in the United States as Native Americans...
s from smallpox having been aware of 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 along the Missouri River
Missouri River
The Missouri River flows through the central United States, and is a tributary of the Mississippi River. It is the longest river in North America and drains the third largest area, though only the thirteenth largest by discharge. The Missouri's watershed encompasses most of the American Great...
during the previous century. One year prior to his special instructions to Lewis, Jefferson had persuaded a visiting delegation
Delegation
Delegation is the assignment of authority and responsibility to another person to carry out specific activities. However the person who delegated the work remains accountable for the outcome of the delegated work. Delegation empowers a subordinate to make decisions, i.e...
of North American Indian Chieftains to be vaccinated with kinepox during the winter of 1801-2. Unfortunately, Lewis never got the opportunity to use kinepox during the pair's expedition as it had become inadvertently inactive — a common occurrence in a time before vaccines were stabilized with preservatives like glycerol
Glycerol
Glycerol is a simple polyol compound. It is a colorless, odorless, viscous liquid that is widely used in pharmaceutical formulations. Glycerol has three hydroxyl groups that are responsible for its solubility in water and its hygroscopic nature. The glycerol backbone is central to all lipids...
or kept at refrigeration temperatures.
Historical use
Antigen
An antigen is a foreign molecule that, when introduced into the body, triggers the production of an antibody by the immune system. The immune system will then kill or neutralize the antigen that is recognized as a foreign and potentially harmful invader. These invaders can be molecules such as...
s and so is able to fight the smallpox disease much more efficiently. The vaccinia virus now used for smallpox vaccination is sufficiently different from the cowpox virus found in the wild as to be considered a separate virus.
The virus contains one hundred and eighty-six thousand base pairs of DNA, which contains the information for about one hundred and eighty-seven genes. This makes smallpox one of the most complicated viruses known. Some one hundred of these genes give instructions for key parts of the human immune system, giving a clue as to why smallpox is so lethal.
Prevention
As cowpox virus was tested to invent a smallpox vaccineSmallpox 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...
, prevention against cowpox is by vaccination against smallpox.