Classification of the causative agent resistance to. Dourine dourine is a chronic venereal disease of horses that is transmitted during coitus and caused by t equiperdum. African horse sickness ahs is an infectious disease of equines caused by one of the nine serotypes of orbivirus. Center for food security and public health, iowa state university, 2011. Evolutionary relationships among the gnattransmitted orbiviruses that cause african horse sickness, bluetongue, and epizootic hemorrhagic disease as evidenced by their capsid protein sequences. This vectorborne, viral disease affects all members of the equidae family. African horse sickness ahs is a disease caused by the african horse. African horse sickness in horses vetlexicon equis from. African horse sickness ahs is caused by a virus of the family reoviridaeof the genus orbivirus. Here we report that all ahsv reference and representative field strains express one of the two forms of ns4, i. Reporting of ahs outbreaks to state veterinary services is compulsory according to the animal disease act, 1984 act 35 of 1984. Fifteen infected ponies and one noninfected control were studied.
African trypanosomiasis, also known as african sleeping sickness or simply sleeping sickness, is an insectborne parasitic infection of humans and other animals. African horse sickness 2 page ct values of infected horses showing clinical signs of ahs are typically in the range of 2030. African horse sickness caused by genome reassortment and. Zebras and donkeys rarely develop serious clinical signs. Fever will be addressed with medication to reduce it, and if there is a need for oxygen supplementation, this will be provided. African horse sickness outbreaks are recorded from 1 september to 31 august of each year. African horse sickness caused by genome reassortment and reversion to virulence of live, attenuated vaccine viruses, south africa, 20042014. Proceedings of the second international symposium 1992. Serotype 9 is widespread in the endemic region, while serotypes 1 to 8 occur in limited areas. Ahs is caused by african horse sickness virus ahsv. The pathogenesis of african horse sickness remains unclear, but this equine orbivirus has an obvious tropism for pulmonary and cardiac endothelial cells and, to a lesser extent, mononuclear cells. Standardization and validation of an immunoperoxidase.
The disease has significant economic consequences for the equine industry both in southern africa and increasingly further afield. Unfortunately, there is no cure for african horse sickness, however supportive care may be offered. A postulated african horse sickness virus overwintering mechanism. Sop manual 12 african horse sickness etiology and ecology 1. A postmortem being carried out on a filly that died of a peracute case dunkop of ahs. Ahs is transmitted by at least two species of culicoides. Ponies exhibited a range of clinical signs and lesions. Epidemiology of african horse sickness and the role of the zebra in south africa. African horse sickness results from infection with the african horse sickness. There are nine serotypes of this virus, and while some serotypes are crossprotective e. Oie manual of diagnostic tests and vaccines for terrestrial animals, 2008. Aetiology epidemiology diagnosis prevention and control references. African horse sickness ahs is a serious arthropodborne viral disease of equids.
Nine different serotypes of the virus have been identified, based on the specificity of its interactions with. Bluetongue, african horse sickness, and related orbiviruses. Human african trypanosomiasis hat is a neglected tropical disease that occurs in subsaharan africa, within the distributional limits of the tsetse fly vector. It is caused by nine different serotypes of the orbivirus african horse sickness virus ahsv and it is spread by culicoid midges. African horse sickness ahs is a noncontagious, infectious disease of equids caused by african horse sickness virus ahsv. Presence of african horse sickness virus in equine tissues. African horse sickness virus dynamics and host responses in naturally infected horses by camilla theresa weyer supervisor. Msc african horse sickness ahs is a life threatening disease of equids caused by african horse sickness virus ahsv, a member of.
African horse sickness ahs was induced in five horses by inoculation, to determine the ultrastructural changes in endothelial cells of capillaries in the myocardium, lung, spleen and liver. Based on clinical signs not pathogenesis, african horse sickness is arbitrarily divided into four different forms. The african horse sickness virus can infect horses, donkeys, mules, zebras, camels and dogs. African horse sickness ahs is a highly infectious and deadly disease caused by african horse sickness virus. Reoviridae, of which there are nine serotypes, all transmitted by. African horse sickness ahs is an insectborne, viral disease of equids that is endemic to subsaharan africa. Oct 19, 2006 underestimate ahs at your peril october 19, 2006 2.
African horse sickness virus ahsv is the causative agent of the often fatal disease african horse sickness in equids. Standardization and validation of an immunoperoxidase assay. Ppt african horse sickness powerpoint presentation. It is caused by a virus of the genus orbivirus belonging to the family reoviridae. Overview of african horse sickness merck veterinary manual. African horse sickness is an economically highly important noncontagious but infectious orbivirus disease that is transmitted by various species of culicoides midges. African horse sickness is a devastating disease that causes great suffering and many fatalities amongst horses in subsaharan africa. African horse sickness ahs is caused by a virus of the family reoviridae of the. Etiology african horse sickness s epidemiology african.
African horse sickness ahs, also called equine plague, 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. African horse sickness perdesiekte at the end of this article is the treatment for horse sickness. An immunoperoxidase assay for the detection of african horse sickness virus ahsv in formalinfixed tissues is a valuable tool in the study of the pathogenesis of the disease, as well as a useful addition to existing diagnostic tests when only preserved tissues are available. There are currently nine recognised serotypes of ahsv worldwide, the last of which was identified in 1960. African horse sickness ahs virus causes a noncontagious, infectious, arthropodborne disease of equines and occasionally of dogs. Find specific details on this topic and related topics from the merck vet manual.
Pdf clinical presentation and pathology of suspected vector. The study of african horse sickness has been mentioned in research publications which can be found using our bioinformatics tool below. Proceedings of the second international symposium provides the latest scientific information about this group of orbiviruses, which are transmitted by species of culicoides biting midges and are important causes of disease in domestic livestock and wildlife. Exercise during the febrile stage of the disease may also precipitate the dunkop form.
Dogs have also been fatally infected after eating virally. At present, ahs virus ahsv is only endemic in africa. Etiology african horse sickness s epidemiology african horse. Aradaib i e 2009 pcr detection of african horse sickness virus serogroup based on genome segment three sequence analysis.
Since 1997, south africa has maintained an ahs controlled area. African horse sickness veterinary research, a journal on animal. There are 9 antigenically distinct serotypes of ahs virus ahsv identified by virus neutralization, but some crossreaction has been observed between 1 and 2, 3 and 7, 5 and 8, and 6 and 9. African horse sickness is a controlled animal disease in terms of the animal diseases act, 1984 act 35 of 1984. Step 1 of 4 compulsory information for a new suspected or confirmed case. African horse sickness virus ahsv antigen was demonstrated immunohistochemically in formalinfixed, paraffinembedded sections of tissues collected from three ponies suffering from the peracute form of the disease and from one pony affected by the fever form. The nonstructural protein ns4 is the only ahsv protein that localizes to the nucleus. African horse sickness ahs is an infectious but non contagious 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.
African horse sickness 2 page fully susceptible horses, such as foals that have lost their colostral immunity or horses that have never been exposed to the ahsv, usually develop the dunkop form of ahs. They where also tested for the herpes virus but in both cases the results where negative. African horse sickness an overview sciencedirect topics. Both forms of ns4 are nucleocytoplasmic proteins, but ns4. Pathogenesis the outcome of infection in horses, including the incubation period and severity of disease, depends. It has long been assumed by british veterinarians and horse owners that the disease, which is carried by midges, could not spread to cooler northern climates. Humans are infected by two types, trypanosoma brucei gambiense tbg and trypanosoma brucei rhodesiense tbr. Immunohistochemical demonstration of african horse sickness. Forty two 42 african horse sickness ahs outbreaks were reported since the start of the 20 ahs cycle on 1 september 2012 as can be seen in table 1. Please take your time to complete the below form as accurately as possible. Pdf african horse sickness ahs is a fatal vector transmitted viral disease of horses caused by the african horse sickness virus ahsv. The ahsv is a doublestranded rna virus from the genus orbivirus family reoviridae, and as such, it is morphologically similar to other orbiviruses such as bluetongue virus btv, epizootic haemorrhagic disease virus ehdv, and equine encephalosis. The possibility that a horse could be infected subclinically with african horse sickness virus ahsv was raised following an outbreak of ahs, in 2006,inthesouthwestofsouthafrica,anareanormallyfreeofthedisease 2.
African horse sickness ahs virus causes a noncontagious, infectious, arthropod borne disease of. The most serious infections occur in horses and mules, which appear to be accidental hosts. Geographic distribution african horse sickness is endemic in subsaharan africa. Tests were done by onderstepoort and the results were that it might be african horse sickness. It has long been assumed by british veterinarians and horseowners that the disease, which is carried by midges, could not spread to cooler northern climates. African horse sickness virus ns4 is a nucleocytoplasmic. For example, medications and therapy to alleviate colic may be offered. May 25, 20 as its name suggests, african horse sickness ahs is associated with the continent of africa, where it is feared as a deadly disease.
Tissue and cell tropism of african horse sickness virus. It is transmitted by the bite of certain culicoides biting midge species. The virus is a noncontagious, vectorborne orbivirus that is. Request pdf african horse sickness summary african horse sickness ahs is a devastating disease of equids caused by an arthropodborne virus belonging to the. Animals that recover from african horse sickness develop good immunity to the infecting serotype and partial immunity to other serotypes. Midges of the culicoides species transmit the disease. The virus is widely distributed across subsaharan african. Mar 27, 2018 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. If the ct value is high 30, it indicates that either the horse has ahs, but the sample was taken either early or late in the course of the infection.
African horse sickness ahs is one of the most lethal systemic illnesses of horses, with mortality rates in susceptible animals of up to 95%. The disease affects horses, ponies, and european donkeys most severely. African horse sickness in naturally infected, immunised horses. Notice of restricted african horse sickness vaccination period posted. Researched pathways related to african horse sickness include pathogenesis, immune response, virulence, reverse transcription, translation. Human african trypanosomiasis hat, also known as sleeping sickness, is caused by protozoan parasites transmitted via the bite of a tsetse fly. Trypanosomiasis circulatory system merck veterinary manual. Possible spread of african horse sickness on the wind. The greatest virus diversity has been reported in southern and eastern africa.
Induction of antibody responses to african horse sickness. African horse sickness ahs is a peracute, acute, subacute or mild infectious but noncontagious disease of equids caused by african horse sickness virus ahsv. Hi, i lost 2 horses in 2006, the first an angloarab colt of 3 years in january and the second an arab filly of almost 2 years in may. Trypanosomosis in cattle is usually chronic some may slowly recover but usually relapse when.
Pathogenesis, clinical findings, lesions, diagnosis, and treatment are similar to those of the tsetsetransmitted trypanosomes see tsetsetransmitted trypanosomiasis. African horse sickness ahs is a disease caused by the african horse sickness virus ahsv. Please contact the relevant provincial director, veterinary services, if the contact details of the. 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. African horse sickness ahs is a hemorrhagic viral fever of horses. African horse sickness the center for food security and public. Overview of african horse sickness generalized conditions. African horse sickness virus dynamics and host responses.
The equids most severely affected by the virus are horses, ponies, and european donkeys. African horse sickness, swelling of supraorbital fossa african horse sickness ahs is an insectborne, viral disease of equids that is endemic to subsaharan africa. The outbreak was thought to have originated from a fully vaccinated horse that showed no clinical signs of ahs and had moved into. The final mechanism by which ahsv may be overwintering, is in a. As its name suggests, african horse sickness ahs is associated with the continent of africa, where it is feared as a deadly disease. Learn about the veterinary topic of overview of african horse sickness. 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. 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 ahs was induced in five horses by inoculation, to determine the ultrastructural changes in endothelial cells of capillaries in the. Ultrastructural study of the capillaries in experimental infection. Immunohistochemical demonstration of african horse. It can be acute, subacute, or subclinical and is characterized by clinical signs and lesions associated with respiratory and circulatory impairment. The slowprogressing form, caused by trypanosoma brucei gambiense, is found in western and central africa. Health, general genomes analysis genomics vaccination vaccines virulence microbiology. After an animal is bitten by culicoides midges, ahsv. African horse sickness results from infection with the african horse sickness virus ahsv, a member of the genus orbivirusin the family reoviridae. African horse sickness ahs is a serious arthropodborne viral disease of equids, with a mortality rate that can reach 95% in some species, such as horses. The outcome of infection in horses, including the incubation period and severity of disease, depends largely on the virulence of the virus and. The african horse sickness trust was set up two years ago to coordinate efforts to contain this deadly. 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. Ahs is not directly contagious, but is known to be spread by insect vectors. The virus is a noncontagious, vectorborne orbivirus that is transmitted primarily by female.
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