Horse flu
Encyclopedia
Equine influenza is the disease caused by strains of Influenza A that are enzootic
in horse
species. Equine influenza occurs globally, and is caused by two main strains of virus: equine-1 (H7N7
) and equine-2 (H3N8
). The disease has a nearly 100% infection rate in an unvaccinated horse population with no prior exposure to the virus.
While equine influenza is historically not known to affect humans, the impact of an outbreak would have been devastating. Since people heavily relied upon horses for communication (postal service), military (cavalry) and general transport, the social and economic impact of widespread equine disease would have been devastating. However, in modern times the ramifications of equine influenza are most clear in the modern racing industry.
Horses with horse flu can run a fever, have a dry hacking cough, have a runny nose, and become depressed and reluctant to eat or drink for several days, but they usually recover in 2 to 3 weeks.
An 1872 report on equine influenza describes the disease as:
Viruses that cause equine influenza were first isolated in 1956.
The viruses can cross the species-barrier to cause an epizootic
disease in humans, and recently, in dogs.
The equine-1 virus affects heart muscle, while the equine-2 virus is much more severe and systemic.
The disease is primarily spread between infected horses. Exposure to infected waste materials (urine and manure) in stables leads to rapid spread of the disease.
and Livius
. Absyrtus
, a Greek veterinarian from 330 CE, described a disease in the horse population having the general characters of influenza, which the report mentions as the earliest clear record of equine influenza in the lower animals.
The report notes the next recorded equine influenza case in 1299, the same year that a catarrh
al epidemic affected Europe. Spanish records note cases in which "The horse carried his head drooping, would eat nothing, ran from the eyes, and there was hurried beating of the flanks. The malady was epidemic, and in that year one thousand horses died."
Prevalence of influenza is found in historic records in the centuries of the Middle Ages, but direct implication of horses is not always clear. Neither are recorded instances of record deaths among horses and other animals clear on the exact cause of death.
in the United States.
The first cases of disease in pasture horses were in the townships of Scarborough
, York
, and Markham
in Ontario
, Canada
. By October 1, 1872, the first case occurred in Toronto
. It took only three days before all the street car horses and major livery
-stables were affected. By the middle of the month, Montreal
, Detroit, and most of the Dominion of Canada and New England reported cases.
By the start of November Ohio
, Massachusetts
, and South Carolina
were reporting cases. So was Chicago
, Illinois
. The contagion reached Florida
and Louisiana
by the end of November and Cuba on December 7. The height of the plague was December 14, when the Mexican government had to supply disease-free horses to the stricken United States. One major factor was that cities were not clean back in those days, which meant that germs spread all that much more quickly (especially through contaminated food and water).
The rate of infected horses approached 100%, and mortality rates ranged between 1% and 10%. Many horses were unable to stand in their stalls. Those that could stand coughed violently and were too weak to pull any loads or support riders.
The street railway industry ground to a halt in late 1872. Every aspect of American transportation was affected. Locomotives came to a halt as coal could not be delivered to power them, while fires in many major cities raged unchecked. One fire in Boston
destroyed over 700 buildings (November 9-10 of that year). Indeed, many a fireman just stood there helpless and horror-stricken, for lack of any equipment to work with. Even the United States Army Cavalry was reduced to fighting on foot against the Apache
s (as the plague had swept not only south to Mexico and Cuba, but also west to the Pacific Ocean within two months!), who likewise found their mounts too sick to do battle. The outbreak forced men to pull wagons by hand; while trains and ships full of cargo sat unloaded (perishables, such as milk, often became spoiled), tram cars stood idle and deliveries of basic community essentials (including food and clothing) were no longer being made. The Long Riders' Guild Academic Foundation founder CuChullaine O'Reilly said, "The Great Epizootic was the worst equestrian catastrophe in the history of the United States - and perhaps the world."
The Great Epizootic of 1872 was also a contributor to the Panic of 1873
, which lasted six years; hence, it would be about seven years total before things were restored to normal operation.
had remained free of equine influenza until an outbreak in August 2007. While the virus was successfully contained and Australia has returned to its equine influenza-free status, the outbreak had significant effects to the country's racing industry.
s (ATCvet codes: inactivated, live, plus various combinations) are a major defense against the disease. Vaccination schedules generally require a primary course of vaccines, followed by booster shots. Standard schedules may not maintain absolutely foolproof levels of protection and more frequent administration is advised in high-risk situations.
The UK requires that horses participating in show events be vaccinated against equine flu, and a vaccination card must be produced; the FEI
requires vaccination every 6 months.
Enzootic
Enzootic is the non-human equivalent of endemic and means, in a broad sense, "belonging to" or "native to", "characteristic of", or "prevalent in" a particular geography, race, field, area, or environment; native to an area or scope....
in horse
Horse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
species. Equine influenza occurs globally, and is caused by two main strains of virus: equine-1 (H7N7
H7N7
H7N7 is a subtype of Influenzavirus A, a genus of Orthomyxovirus, the viruses responsible for influenza. Highly pathogenic strains and low pathogenic strains exist. H7N7 can infect humans, birds, pigs, seals, and horses in the wild; and has infected mice in laboratory studies...
) and equine-2 (H3N8
H3N8
H3N8 is a subtype of the species Influenza A virus that is endemic in birds, horses and dogs.-Introduction:Equine influenza is a highly contagious respiratorydisease of horses and related animals such as donkeys,...
). The disease has a nearly 100% infection rate in an unvaccinated horse population with no prior exposure to the virus.
While equine influenza is historically not known to affect humans, the impact of an outbreak would have been devastating. Since people heavily relied upon horses for communication (postal service), military (cavalry) and general transport, the social and economic impact of widespread equine disease would have been devastating. However, in modern times the ramifications of equine influenza are most clear in the modern racing industry.
Characteristics
Equine influenza is characterized by a very high rate of transmission among horses, and has a relatively short incubation time of 1–5 days.Horses with horse flu can run a fever, have a dry hacking cough, have a runny nose, and become depressed and reluctant to eat or drink for several days, but they usually recover in 2 to 3 weeks.
An 1872 report on equine influenza describes the disease as:
Causes
Equine influenza is caused by several strains of the Influenza A virus endemic to horses.Viruses that cause equine influenza were first isolated in 1956.
The viruses can cross the species-barrier to cause an epizootic
Epizootic
In epizoology, an epizootic is a disease that appears as new cases in a given animal population, during a given period, at a rate that substantially exceeds what is "expected" based on recent experience . Epidemic is the analogous term applied to human populations...
disease in humans, and recently, in dogs.
The equine-1 virus affects heart muscle, while the equine-2 virus is much more severe and systemic.
The disease is primarily spread between infected horses. Exposure to infected waste materials (urine and manure) in stables leads to rapid spread of the disease.
History
A comprehensive report describing the disease - compiled in response to the 1872 outbreak of the disease in North America - provided a thorough examination of the history of the disease.Early records
The report notes putative cases dating as far back as HippocratesHippocrates
Hippocrates of Cos or Hippokrates of Kos was an ancient Greek physician of the Age of Pericles , and is considered one of the most outstanding figures in the history of medicine...
and Livius
Livius
Livius is the nomen of an individual male of the Livia gens, a family of ancient Rome. Collectively they were termed the Livii . Any individual female was called Livia. Both male and female names might be qualified by one or more agnomina. Males in addition had a praenomen...
. Absyrtus
Absyrtus
Absyrtus, or Apsyrtus , was in Greek mythology the son of Aeëtes and a brother of Medea and Chalciope. His mother is variously given: Hyginus calls her Ipsia, Hesiod and Apollodorus call her Eidyia, Apollonius calls her Asterodeia, and others Neaera or Eurylyte.When Medea fled with Jason, she took...
, a Greek veterinarian from 330 CE, described a disease in the horse population having the general characters of influenza, which the report mentions as the earliest clear record of equine influenza in the lower animals.
The report notes the next recorded equine influenza case in 1299, the same year that a catarrh
Catarrh
Catarrh is a disorder of inflammation of the mucous membranes in one of the airways or cavities of the body. It can result in a thick exudate of mucus and white blood cells caused by the swelling of the mucous membranes in the head in response to an infection...
al epidemic affected Europe. Spanish records note cases in which "The horse carried his head drooping, would eat nothing, ran from the eyes, and there was hurried beating of the flanks. The malady was epidemic, and in that year one thousand horses died."
Prevalence of influenza is found in historic records in the centuries of the Middle Ages, but direct implication of horses is not always clear. Neither are recorded instances of record deaths among horses and other animals clear on the exact cause of death.
1872 American outbreak
An epizootic outbreak of equine influenza during 1872 in North America became known as "The Great Epizootic of 1872." The outbreak is known as the "most destructive recorded episode of equine influenza in history." The impact of the outbreak is marked as one of the major contributors to the Panic of 1873Panic of 1873
The Panic of 1873 triggered a severe international economic depression in both Europe and the United States that lasted until 1879, and even longer in some countries. The depression was known as the Great Depression until the 1930s, but is now known as the Long Depression...
in the United States.
The first cases of disease in pasture horses were in the townships of Scarborough
Scarborough, Ontario
Scarborough is a dissolved municipality within the city of Toronto, Ontario, Canada. Geographically, it comprises the eastern part of Toronto. It is bordered on the south by Lake Ontario, on the west by Victoria Park Avenue, on the north by Steeles Avenue East, and on the east by the Rouge River...
, York
York, Ontario
York is a dissolved municipality in Toronto, Ontario, Canada. Geographically, it is located northwest of Old Toronto, southwest of North York and east of Etobicoke, where it is bounded by the Humber River. Formerly a separate city, it was one of six municipalities that amalgamated in 1998 to form...
, and Markham
Markham, Ontario
Markham is a town in the Regional Municipality of York, located within the Greater Toronto Area of Southern Ontario, Canada. The population was 261,573 at the 2006 Canadian census...
in Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
, 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 October 1, 1872, the first case occurred in Toronto
Toronto
Toronto is the provincial capital of Ontario and the largest city in Canada. It is located in Southern Ontario on the northwestern shore of Lake Ontario. A relatively modern city, Toronto's history dates back to the late-18th century, when its land was first purchased by the British monarchy from...
. It took only three days before all the street car horses and major livery
Livery
A livery is a uniform, insignia or symbol adorning, in a non-military context, a person, an object or a vehicle that denotes a relationship between the wearer of the livery and an individual or corporate body. Often, elements of the heraldry relating to the individual or corporate body feature in...
-stables were affected. By the middle of the month, Montreal
Montreal
Montreal is a city in Canada. It is the largest city in the province of Quebec, the second-largest city in Canada and the seventh largest in North America...
, Detroit, and most of the Dominion of Canada and New England reported cases.
By the start of November Ohio
Ohio
Ohio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...
, 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...
, and South Carolina
South Carolina
South Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...
were reporting cases. So was Chicago
Chicago
Chicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...
, Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...
. The contagion reached Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
and Louisiana
Louisiana
Louisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state in the U.S. with political subdivisions termed parishes, which are local governments equivalent to counties...
by the end of November and Cuba on December 7. The height of the plague was December 14, when the Mexican government had to supply disease-free horses to the stricken United States. One major factor was that cities were not clean back in those days, which meant that germs spread all that much more quickly (especially through contaminated food and water).
The rate of infected horses approached 100%, and mortality rates ranged between 1% and 10%. Many horses were unable to stand in their stalls. Those that could stand coughed violently and were too weak to pull any loads or support riders.
The street railway industry ground to a halt in late 1872. Every aspect of American transportation was affected. Locomotives came to a halt as coal could not be delivered to power them, while fires in many major cities raged unchecked. One fire in Boston
Great Boston Fire of 1872
The Great Boston Fire of 1872 was Boston's largest urban fire, and still ranks as one of the most costly fire-related property losses in American history. The conflagration began at 7:20 p.m. on November 9, 1872, in the basement of a commercial warehouse at 83—87 Summer Street in Boston,...
destroyed over 700 buildings (November 9-10 of that year). Indeed, many a fireman just stood there helpless and horror-stricken, for lack of any equipment to work with. Even the United States Army Cavalry was reduced to fighting on foot against the Apache
Apache
Apache is the collective term for several culturally related groups of Native Americans in the United States originally from the Southwest United States. These indigenous peoples of North America speak a Southern Athabaskan language, which is related linguistically to the languages of Athabaskan...
s (as the plague had swept not only south to Mexico and Cuba, but also west to the Pacific Ocean within two months!), who likewise found their mounts too sick to do battle. The outbreak forced men to pull wagons by hand; while trains and ships full of cargo sat unloaded (perishables, such as milk, often became spoiled), tram cars stood idle and deliveries of basic community essentials (including food and clothing) were no longer being made. The Long Riders' Guild Academic Foundation founder CuChullaine O'Reilly said, "The Great Epizootic was the worst equestrian catastrophe in the history of the United States - and perhaps the world."
The Great Epizootic of 1872 was also a contributor to the Panic of 1873
Panic of 1873
The Panic of 1873 triggered a severe international economic depression in both Europe and the United States that lasted until 1879, and even longer in some countries. The depression was known as the Great Depression until the 1930s, but is now known as the Long Depression...
, which lasted six years; hence, it would be about seven years total before things were restored to normal operation.
2007 Australian outbreak
The continent/country of AustraliaAustralia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
had remained free of equine influenza until an outbreak in August 2007. While the virus was successfully contained and Australia has returned to its equine influenza-free status, the outbreak had significant effects to the country's racing industry.
Prevention
Prevention of equine influenza outbreaks are maintained through vaccines and hygiene procedures. Countries that are equine influenza-free will normally impose strict and rigorous quarantine measures.Vaccines
VaccineVaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...
s (ATCvet codes: inactivated, live, plus various combinations) are a major defense against the disease. Vaccination schedules generally require a primary course of vaccines, followed by booster shots. Standard schedules may not maintain absolutely foolproof levels of protection and more frequent administration is advised in high-risk situations.
The UK requires that horses participating in show events be vaccinated against equine flu, and a vaccination card must be produced; the FEI
International Federation for Equestrian Sports
The Fédération Équestre Internationale or in English, the International Federation for Equestrian Sports, is the international governing body of equestrian sports. It recognizes ten international disciplines...
requires vaccination every 6 months.
Sources and notes
External links
- EI Vaccination Debate - Australia equinetrader.co.nz
- COntrolling Equine Influenza - Japan equinetrader.co.nz
- Great Epizootic of 1872 equinetrader.co.nz
- Caring for a horse with equine influenza Horsetalk.co.nz (NZ)
- Equine flu resources: Q&A, latest news, contacts Horsetalk.co.nz (NZ)
- Veterinary Record
- Equine Quarterly Disease Surveillance Reports
- Horse Flu