In the period to , serotype 9 affected many countries in the Middle East, getting its eradication through mass vaccination campaign. In the same serotype appeared in Morocco, after spread to Algeria and Tunisia, and crossed the Strait of Gibraltar, arriving to Spain in October Spain achieved viral eradication after application of an intense vaccination campaign. Until no outbreak were declared in non-endemic area, being reported this year an AHS outbreak of serotype 4 in Spain. This outbreak was caused by the importation of subclinical infected zebras to a safari of the Community of Madrid.
African horse sickness
Outbreaks lasted until October in the centre of the country. However, secondary outbreaks were declared in the South, which were not eradicated until In , the outbreak in Spain spread to Portugal, which eradicated that year, and Morocco, where the virus remained until Since the countries that have reported the disease to the World Organization for Animal Health OIE were Botswana last notification in , Eritrea last notification in , Ghana last notification in , Lesotho last notification in , Namibia last notification in , Somalia last notification in , Swaziland last notification in , South Africa last notification in and Ethiopia last notification in , the endemic disease has been declared.
Despite health measures performed at the borders of the European Union EU the AHS recurrence is possible in our country due to the incessant movements of horses for sport competitions or trade and transmission by vectors, since they can move long distances and have increased their range due to global warming. The presence of this disease in a country causes important restrictions on equidae trade, seriously affecting economic, sports and cultural activities.
With the emergence of an outbreak, early suspicions are based on clinical signs and prevalence of vectors in the area. However, laboratory diagnosis is essential to establish a correct and confirmatory diagnosis. They can be divided into two groups:.
They can be divided into two groups The recommendations contained in these legislations are based on:. Vaccination is the most effective measure to minimize losses associated with the disease, eventually interrupt the cycle of the animal to the vector and allow the eradication of the disease. There are several types of vaccines against AHS:. One of the control measures against the African Horse Sickness AHS is vaccination of uninfected animals of susceptible species together with their identification, only if the applicable law allows it see Prevention and control of disease.
Vaccination strategies in a zone must include all animals of the genus Equus horses, donkeys, asses, zebras and onagers. This measure will also ensure long-term eradication of the disease. The fact that an animal has been vaccinated against one AHS serotype does not totally protect against other AHS serotypes, since the vaccination only protects fully against the same antigenic variants. In Spain, we used two types of vaccines for the control and eradication of the disease.
At the outbreak of in Campo de Gibraltar a mass vaccination of , animals was carried out with polyvalent live attenuated vaccines, achieving the eradication of the disease in December Similarly, at the outbreak of eradication of the disease was also achieved through vaccination. In and , the campaign of vaccination was made with polyvalent live attenuated vaccines.
However, in the vaccination was performed with monovalent inactivated vaccines. Research lines Animal thermography Marine animal health Emerg.
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Team photos Event photos Media library Search Historical evolution of the disease African Horse Sickness AHS is enzootic in tropical and subtropical regions of Sub-Saharan Africa and Yemen, where outbreaks of disease are regularly reported in domestic equidae. Diagnosis of the African Horse Sickness With the emergence of an outbreak, early suspicions are based on clinical signs and prevalence of vectors in the area. They can be divided into two groups: With the emergence of an outbreak, early suspicions are based on clinical signs and prevalence of vectors in the area.
They can be divided into two groups:: Identification of the agent: Isolation of AHSV in cell culture, in embryonated eggs or in newborm mice. Serological tests: Complement fixation test. Serotyping by virus-neutralization detecting serotype-specific antibody of AHS virus. Swelling may extend to the eyelids, facial tissues, neck, thorax, brisket, and shoulders. Death usually occurs within 1 wk and may be preceded by colic.
Petechiae and ecchymoses on the epicardium and endocardium are prominent. The lungs are usually flaccid or slightly edematous. There are yellow, gelatinous infiltrations of the subcutaneous and intramuscular tissues, especially along the jugular veins and ligamentum nuchae. Other lesions include hydropericardium, myocarditis, hemorrhagic gastritis, and petechiae on the ventral surface of the tongue and peritoneum.
Subclinical AHSV infection occurs in partially immune equids, such as those previously vaccinated against the disease, or in equids naturally infected with live-attenuated vaccine strains of AHSV. Subclinical infections are also characteristic in zebras and certain other equids. In endemic areas, clinical signs and lesions may lead to a presumptive diagnosis.
However, laboratory confirmation is essential for definitive diagnosis and determination of the serotype; the latter is important for control measures. Spleen samples collected from freshly dead animals should be kept on ice. Presence of virus is best detected by group-specific reverse-transcriptase polymerase chain reaction RT-PCR. AHSV also can be isolated by intracerebral inoculation of suckling mice or in mammalian or insect cell cultures.
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Although not widely available, indirect sandwich ELISA is also useful for rapid identification of AHSV antigen in tissues from animals that have died from acute infection. There is no specific treatment for animals with AHS apart from rest and good husbandry. Complicating and secondary infections should be treated appropriately during recovery. AHSV is typically noncontagious and spread exclusively via the bites of infected Culicoides spp or by the direct inoculation of infectious material via blood-feeding insects, needles, etc.
Various methods of control may be attempted, such as introducing animal movement restrictions to prevent infected animals initiating new foci of infection, and husbandry modification to deny or reduce vector access to susceptible or infected animals eg, stabling in vector-proof housing. It is rarely possible to completely eliminate populations of vector Culicoides , especially in extensive pasture systems. Live-attenuated virus vaccines are available for immunization of equids against AHS.
African Horse Sickness (AHS) | Health Information & Advice | British Horse Society (BHS)
These are typically based on cell culture—attenuated viruses and generally provide good, but not absolute, protection. Annual revaccination is recommended in regions where these vaccines are used. However, there are increasing concerns regarding use of live-attenuated AHSV vaccines because of their potential reversion to virulence, capacity for transmission by vector Culicoides midges, and reassortment of their gene segments with other vaccine and field strains of virus, leading to the creation of novel virus progeny.
Inactivated and subunit vaccines avoid these potential drawbacks and, assuming they are commercially available, would likely be used after incursion of AHSV into previously unaffected regions. Transport of equids from countries where AHSV occurs to virus-free areas is subject to strict regimens of testing and quarantine, although the precise requirements may vary from country to country. The presence of antibodies alone should not preclude such movements as long as AHSV is not present.
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Common Veterinary Topics. Videos Figures Images Quizzes. Etiology and Epidemiology:. Clinical Findings and Lesions:. Prevention and Control:. Test your knowledge. Anaerobic clostridial bacteria release toxins that can cause severe localized and systemic disease, many of which can be fatal if untreated.