Table of contents overview of horse sickness in south africa what is ahs 2 host and vector 2 how do horses contract the disease 2 signs of ahs 2 diagnosis and notification 2 supportive treatment 3 recent outbreaks ahs trust reports 4 outbreak reports 20002009 4 reporting procedures 5 protection methods vaccinations 6 additional protection. Apart from venezuelan equine encephalitis, it is the most important viral disease capable of causing widespread mortality in horses. African horse sickness ahs is a devastating disease of equids caused by an arthropodborne virus belonging to the reoviridae family, genus orbivirus. African horse sickness is an insectborne culicoides spp. African horse sickness is a disease that affects equidae that is, horses, donkeys and mules. There are nine ahsv serotypes with significant genomic differences. It is considered a major health threat for horses in endemic areas in subsaharan africa. If african horse sickness is confirmed, the outbreak will be controlled in line with the contingency plan for exotic.
The ahsv genome consists of 10 segments of doublestranded rna dsrna collectively encoding seven structural proteins and four nonstructural proteins. This disease is on the list of diseases notifiable to the world organisation for animal health oie. Transmitted by insects, diseases such as west nile virus, swamp. A spatiotemporal model to assess the introduction risk of.
It is lethal in up to 95 % of its hosts, including horses, zebras, donkeys, camels, dogs, and mules, and it is carried by two different species of arthropods. African horse sickness virus causes disease in horses, mules, and donkeys with up to 95% mortality. It is classified as an orbivirus of the reoviridae family of which there are 9 serotypes. African horse sickness is a highly infectious, noncontagious, insecttransmitted disease affecting all species of equidae. African horse sickness virus ahsv is a viral disease transmitted by the biting midge. Complete genome sequences of four african horse sickness. It is an infectious and fatal disease and is classified as an orbivirus. Animals that recover from african horse sickness develop good immunity to the infecting serotype and partial immunity to other serotypes. Since 1997, south africa has maintained an ahs controlled area. It is the only equine disease for which the world organization for animal health has introduced specific guidelines for member countries seeking official recognition of diseasefree status. Riskassessmentoftheintroductionofafricanhorsesickness230311. The greatest virus diversity has been reported in southern and eastern africa.
It is caused by nine different serotypes of the orbivirus. African horse sickness equine including zebra serum red top tube 10 ml faddl whole blood green top tube 10 ml purple top tube 10 ml fresh tissue. It does not spread directly from one horse to another, but is transmitted by the culicoides midge, which becomes infected when feeding on other infected equidae. Spleen, ln, lung separate whirlpak bag per tissue type set of tissues formalin 10. African horse sickness has long been known to infect and cause mortality among domestic dogs that ingest virus contaminated meat, but it is uncertain what role. Overview of african horse sickness generalized conditions. Serotype 9 is widespread in the endemic region, while serotypes 1 to 8 occur in limited areas.
What does this mean to you as a concerned horse owner. Possible spread of african horse sickness on the wind. At the time of writing, there have been 23 confirmed cases of african horse sickness ahs in south africa. African horse sickness is a devastating disease that causes great suffering and many fatalities amongst horses in subsaharan africa. The disease is characterised by alterations in respiratory and circulatory functions. The disease is infectious but not contagious and is transmitted by the bite of culicoides midges with the most important vector being culicoides imicola. African horse sickness 9 page laboratory confirmation the epidemiology, clinical signs and gross lesions of ahs are often sufficiently specific to allow a provisional diagnosis of the disease to be made. Midges of the culicoides species transmit the disease. History of ahs 27 yemen arabic document 1569 east africa portuguese explorers 1719 south africa cape colony introduction. The uk equine population is now vulnerable to viruses that no one ever believed would be seen on our shores. To confirm the diagnosis, the virus should be isolated. Ppt african horse sickness powerpoint presentation.
African horse sickness ahs is an insectborne, viral disease of equids that is endemic to subsaharan africa. Etiology african horse sickness s epidemiology african horse. We have known for some time that domestic dogs are capable of being infected with ahsv and, apart from horses, the domestic dog is the only other species known to contract the severe form of the disease. A possible role for domestic dogs in the spread of african. Reoviridae, of which there are nine serotypes, all transmitted by. Classification of the causative agent resistance to. African horse sickness ahs is a highly infectious noncontagious, vector born viral disease affecting all species of equidae. African horse sickness outbreak in the northern parts of south africa in most of south africa, except for a part of the western cape province, african horse sickness ahs is endemic and the area is known as an ahs infected zone. African horse sickness ahs is an arboviral disease of equids transmitted by culicoides biting midges. A postmortem being carried out on a filly that died of a peracute case dunkop of ahs.
African horse sickness is a serious, often fatal disease of horses, mules, and donkeys. African horse sickness ahs is a highly infectious, noncontagious, vectorborne viral disease affecting all species of equidae. Dunkop or pulmonary form this form of the disease occurs commonly when ahsv infects fully susceptible horses, notably. Aug 25, 2017 each year, i am one of thousands of horse owners in south africa who spends six months anxiously awaiting the end of insect season. African horse sickness is an economically highly important noncontagious but infectious orbivirus disease that is transmitted by various species of culicoides midges. The key to treating ahs is to learn about it, recognise early symptoms and, primarily, prevent the disease as best as possible. Could domestic dogs be involved in african horse sickness virus ahsv transmission. It is caused by one or more of the nine different serotypes of an orbivirus of the family reoviridae. The document is structured with the following broad sections that follow events as they might. African horse sickness african horse sickness ahs is a viral disease with an extremely high mortality rate.
The spread of the disease is similar to bluetongue, in that it is not directly contagious between horses as it is influenced by climatic conditions which favour the spread of carrier. An african horse sickness is a highly disease is endemic in tropical and subtropical areas of fatal insect born viral disease of horses, mules and africa south of the sahara, occupying abroad band generally subclinical diseases in. Ahs surveillance zone permission for vaccination will only. African horse sickness virus ns4 is a nucleocytoplasmic. The nonstructural protein ns4 is the only ahsv protein that localizes to the nucleus. African horse sickness virus ahsv belongs to the genus orbivirus in the family reoviridae and is transmitted by culicoides species midges, of which c. This disease can be caused by any of the nine serotypes of this virus.
Abstract african horse sickness virus ahsv causes a noncontagious, infectious insectborne disease of equids and is endemic in many areas of. African horse sickness ahs is a noncontagious viral disease affecting all species of equidae. African horse sickness in horses vetlexicon equis from. African horse sickness alan guthrie equine research centre faculty of veterinary science university of pretoria onderstepoort south africa introduction. Thailand reported an outbreak of african horse sickness ahs on 27 march, in horses from multiple barns across the district of pak chong, in the north eastern region of the country. African horse sickness virus ahsv repeatedly caused large epizootics. Preliminary outbreak assessment for african horse sickness in horses from multiple barns across the district of. By law, a spleen sample must be taken to confirm the diagnosis. The disease affects horses, ponies, and european donkeys most severely. The obvious first step is to monitor your horse for ahs. The disease has significant economic consequences for the equine industry both in southern africa and increasingly further afield.
Aug 26, 2014 if you report suspicion of african horse sickness apha vets will investigate. African horse sickness ahs is an infectious disease of equines caused by one of the nine serotypes of orbivirus. Analyses of outbreaks of african horse sickness showed that movement of infected culicoides midges on the wind was most likely responsible for the spread of the disease over the sea from morocco to spain in 1966, from turkey to cyprus in 1960, and from senegal to. The foreign animal disease preparedness and response plan fad prep standard operating. African horse sickness ahs, disease of equidae horses, mules, donkeys, and zebras caused by an orbivirus called ahsv family reoviridae that is transmitted by arthropods, notably biting midges culicoides imicola. Here we report that all ahsv reference and representative field strains express one of the two forms of ns4, i. There are 9 antigenically distinct serotypes of ahs virus ahsv identified by virus neutralization, but some. Due to the nature of the disease, any animals suspected of having african horse sickness will be isolated and movement restrictions put in place. African horse sickness is a highly fatal and infectious disease, which affects horses, mules, donkeys and zebras. The ahs trust has undertaken to assist the department of agriculture with the reporting of outbreaks. African horse sickness ahs is a major, culicoidesborne viral disease in equines whose introduction into europe could have dramatic consequences. African horse sickness veterinary research, a journal on animal.
Both forms of ns4 are nucleocytoplasmic proteins, but ns4. African horse sickness caused by genome reassortment and. African horse sickness ahs is caused by a virus of the family reoviridae of the genus orbivirus. For us, biting midges are more than simply a nuisancethey are a mortal threat to our horses because they can carry the virus that causes african horse sickness ahs, an untreatable and potentially fatal disease. African horse sickness ahs is a serious arthropodborne viral disease of equids. The equids most severely affected by the virus are horses, ponies, and european donkeys.
African horse sickness ahs is an infectious but noncontagious viral disease affecting all species of equidae caused by an orbivirus of the family reoviridae and characterised by alterations in the respiratory and circulatory functions. Diseases and control measures the eu has a set of specific legislation for a number of animal diseases depending on their potential social and economic impact. The severity of african horse sickness ahs is strongly linked to the immunity status of the horse concerned, and the dose of the virus it receives from biting midges. African horse sickness aetiology epidemiology diagnosis prevention and control references aetiology classification of the causative agent african horse sickness ahs is caused by a virus of the family reoviridae of the genus orbivirus.
Area adjustment ahs free zone permission for vaccination will only be given from 1 june to 31 october each year. Ahs is almost exclusively a disease of equids and is not considered zoonotic, although disease associated with the virus has been described in people following nasal exposure to virus from broken vaccine vials. Geographic distribution african horse sickness is endemic in subsaharan africa. African horse sickness question and answer diseases once associated with foreign climes are now, as a result of climate change, more likely to pose a threat to the uk. Pdf seroepidemiological study of african horse sickness. Unfortunately, outbreaks of ahs are expected to occur in the ahs infected zone from november to may. This disease is endemic to subsaharan africa, however outbreaks have been seen in egypt, the middle east and southern arabia. Apr 26, 2014 at the time of writing, there have been 23 confirmed cases of african horse sickness ahs in south africa. It can be acute, subacute, or subclinical and is characterized by clinical signs and lesions associated with respiratory and circulatory impairment. African horse sickness ahs is a disease caused by the african horse. The virus is transmitted between horses primarily by midge bites and occasionally by mosquitoes and ticks. Fever lasting 3 to 8 days mild anorexia or depression.
African horse sickness ahs is a hemorrhagic viral fever of horses. African horse sickness an overview sciencedirect topics. African horse sickness is an infectious but noncontagious. African horse sickness ahs is a disease that affects all equid species, and is caused by african horse sickness virus ahsvan orbivirus of the reoviridae family. Recent introductions of other culicoidesborne viruses bluetongue and schmallenberg into northern europe have. There are nine serotypes of this virus, and while some serotypes are crossprotective e. In mules, the mortality rate is approximately 50%, and in european and asian donkeys, 5% to 10%. The disease is capable of causing severe illness and death in horses, which may adversely affect the livelihoods of the owners of working and sporting animals and the communities that depend upon them. Ashv is a pathogenic virus that causes african horse sickness. All serotypes 19 are distributed throughout south africa, although there is a variation in.
Dec 19, 2012 the african horse sickness control strategy was developed by a working group chaired by the horse trust, and involving the equine industry, research organisations, defra and the devolved. African horse sickness emerging pathogens institute. African horse sickness is endemic or occurs in all parts of africa south of the sahara but epidemics have spread further north to egypt, the middle east and spain. The disease has never been recorded in north america. It is characterized by respiratory and circulatory damage. African horse sickness perdesiekte at the end of this article is the treatment for horse sickness. There are 9 antigenically distinct serotypes of ahs virus. Look out for these symptoms of african horse sickness. It is caused by a virus of the genus orbivirus belonging to the family reoviridae. This disease often spreads to southern africa and occasionally to northern africa. The disease is considered to be endemic in subsaharan africa. African horse sickness virus ahsv is a lethal arbovirus of equids that is transmitted between hosts primarily by biting midges of the genus diptera. African horse sickness ahs is a disease caused by the african horse sickness virus ahsv.
Australia has not recorded any outbreaks of african horse sickness, which is caused by an insecttransmitted virus. This vectorborne, viral disease affects all members of the equidae family. The disease, which is not usually fatal to indigenous zebra herds, is often. African horse sickness ahs is a viral disease of equids horses, donkeys, mules and zebras that is transmitted by culicoides midges. The african horse sickness wales regulations 20 provide the legal powers to allow the control of african horse sickness ahs. Ahsv affects draft, thoroughbred, and companion horses and donkeys in africa, asia, and europe. African horse sickness ahs is a peracute, acute, subacute or mild infectious but noncontagious disease of equids caused by african horse sickness virus ahsv.
An african horse sickness is a highly disease is endemic in tropical and subtropical areas of fatal insect born viral disease of horses, mules and africa south of the sahara, occupying abroad band generally subclinical diseases in other equidae. Surviving african horse sickness the horse owners resource. The african horse sickness scotland order 2012 and. African horse sickness is endemic in subsaharan central and east africa.
African horse sickness ahs is an arthropodborne equine disease caused by african horse sickness virus ahsv genus orbivirus, family reoviridae. Mar 27, 2018 if the horse survives the first stage the lung stage, it may start showing cardiac signs, and the vet will start to treat symptomatically with a different range of drugs to improve heart function. African horse sickness 1959 when it spread to iran and pakistan 17. Answers from doctors on african horse sickness symptoms. Bluetongue, african horse sickness and related orbiviruses. In severe cases, you may have to get the vet in daily for several days, or hospitalise the horse for intensive care. If you report suspicion of african horse sickness apha vets will investigate. African horse sickness the center for food security and public. African horse sickness virus ahsv causes a noncontagious, infectious insectborne disease of equids and is endemic in many areas of subsaharan africa and possibly yemen in the arabian peninsula. Outbreaks have been seen in egypt and other parts of the middle east, as well as in spain. Sop manual 12 african horse sickness etiology and ecology 1.
Diagnosis and differential diagnosis clinical signs and pathology four clinical forms of ahs have been described the dunkop or pulmonary, dikkop or cardiac, mixed and horse sickness fever forms. Etiology african horse sickness s epidemiology african. African horse sickness results from infection with the african horse sickness virus ahsv, a member of the genus orbivirus in the family reoviridae. It is caused by nine different serotypes of the orbivirus african horse sickness virus ahsv and it is spread by culicoid midges. A crosssectional study was carried out from november 2009 to mid of march 2010 to determine the seroprevalence of african horse sickness antibodies in the equine population of three selected districtsdamot gale, shashogo and bonke woredasof the. Epizootics of african horse sickness have been recognized in south africa since 1780. The virus is a noncontagious, vectorborne orbivirus that is transmitted primarily by female. This is a noncontagious viral disease that affects all equidae horses, ponies, mules, donkeys, zebras and other hybrids. The occurrence is seasonal because the insect vectors thrive in hot, wet conditions. African horse sickness virus ahsv is the causative agent of the often fatal disease african horse sickness in equids. African horse sickness ahs is a highly infectious and deadly disease caused by african horse sickness virus. African horse sickness virus an overview sciencedirect. The authorities have mentioned that the severity of the outbreak was unexpected.
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