African horse sickness
African horse sickness virus | |
---|---|
Virus classification | |
(unranked): | Virus |
Realm: | Riboviria |
Kingdom: | Orthornavirae |
Phylum: | Duplornaviricota |
Class: | Resentoviricetes |
Order: | Reovirales
|
Family: | Sedoreoviridae |
Genus: | Orbivirus |
Species: | African horse sickness virus
|
African horse sickness (AHS) is a highly infectious and often fatal
Epidemiology
AHS virus was first recorded south of the Sahara Desert in the mid-1600s, with the introduction of horses to southern Africa. The virus is considered endemic to the equatorial, eastern, and southern regions of Africa. Several outbreaks have occurred in the Equidae throughout Africa and elsewhere.
Host
The common hosts of this disease are horses, mules, donkeys, and zebras. However, elephants, camels, and dogs can be infected, as well, but often show no signs of the disease and it is very rare. Dogs usually contract the disease by eating infected horse meat, although a recent report has been made of the disease occurring in dogs with no known horse-meat ingestion.[3]
Transmission
This disease is spread by insect vectors. The biological vector of the virus is the
Clinical signs
Horses are the most susceptible host with close to 90%
Pulmonary form
The
Cardiac form
This
Mild or horse sickness fever form
Mild to subclinical disease is seen in zebras and African donkeys. Infected animals may have a low-grade fever and congested mucous membrane. The survival rate is 100%.
Mixed form
Diagnosis is made at necropsy. Affected horses show signs of both the pulmonary and cardiac forms of AHS. This form probably has the highest mortality rate of all the forms. Not many survive this.
Diagnosis
Presumptive diagnosis is made by characteristic clinical signs, post mortem lesions, and presence of competent vectors. Laboratory confirmation is by viral isolation, with such techniques as
Treatment and prevention
No treatment for AHS is known.[7]
Control of an outbreak in an endemic region involves quarantine, vector control, and
History
African horse sickness was diagnosed in Spain in 1987–90 and in Portugal in 1989, but was eradicated using slaughter policies, movement restrictions, vector eradication, and vaccination.[5]
Infection was reported in Pak Chong district of Nakhon Ratchasima province in Thailand in March 2020 when 42 racehorses died from an unknown illness which was later confirmed to be African Horse Sickness virus serotype 1.[10]
Related diseases
AHS is related to bluetongue disease and is spread by the same midge (Culicoides species).[citation needed]
References
- ^ "ICTV 9th Report (2011) Reoviridae" (html). International Committee on Taxonomy of Viruses (ICTV). Retrieved 17 January 2019.
- ^ CIDRAP >> African Horse Sickness Archived July 12, 2010, at the Wayback Machine
- hdl:2263/36753.
- PMID 28141961.
- ^ a b "Lethal horse disease knocking on Europe's door" (Press release). Unknown. 2007-03-28. Retrieved 2007-03-27.
- ^ The Merck Veterinary Manual – African Horse Sickness – Clinical Findings and Lesions
- ^ "AFRICAN HORSE SICKNESS" (PDF). OIE - World Organisation for Animal Health. OIE - World Organisation for Animal Healthwww.oie.int. Retrieved 29 June 2020.
- ^ "African Horse Sickness". Animal Research Info. Retrieved 29 June 2020.
- ^ "African Horse Sickness" (PDF). Iowa State University. Retrieved 29 June 2020.
- S2CID 220130174.
External links
- Disease card from the World Organisation for Animal Health (OIE)
- Current status of African Horse Sickness worldwide at World Organisation for Animal Health (OIE). WAHID Interface – OIE World Animal Health Information Database
- CIDRAP Overview on African Horse Sickness
- 3D electron microscopy structures of the African horse sickness virus from the EM Data Bank(EMDB)
- The role of conserved residues in African horsesickness virus protein NS3 in intracellular localisation and cytotoxicity