Equine Viral Arteritis: Causes, Symptoms ,Prevention and treatment

Equine Viral Arteritis is a contagious viral disease of horses and other equine species caused by equine arteritis virus (EAV), an RNA virus of the species Alphaarterivirus equid¹.In this disease, viruses cause different problems in respiratory and reproductive systems. Equine arterivirus(EVA) is a contagious disease of horses caused by an RNA virus that can be found in many countries among horse communities. It can cause abortion in pregnant mares, respiratory illness, death in young foals, and carrier state in stallions. Most horses infected with EVA show minimal or no clinical signs, but some may develop fever, depression, nasal discharge, swelling of the limbs, scrotum or eyelids, and skin rash.

Clinical findings of Equine herpesvirus-3 (EHV-3) :

  • Clinical signs of equine viral arteritis vary considerably among individual horses and outbreaks.
  • Exposure to equine arteritis virus may result in clinical or asymptomatic infection, depending on the relative virulence of the strain involved, viral dose, age and physical condition of the animal, and various environmental factors.
  • Most cases of primary infection are asymptomatic.
  • Onset of the acute phase of EAV infection, whether associated with clinical signs or not, is preceded by an incubation period of 2–14 days, which varies mainly with the route of exposure.
  • The interval can be 2–3 days after respiratory exposure and is usually 6–8 days after venereal transmission of the virus.
  • Clinical signs can differ in range and severity between outbreaks and between individuals in the same outbreak. Any combination of the following clinical signs may be observed:
  • Fever (up to 41°C), depression, anorexia, leukopenia, dependent edema (limbs, centrum, scrotum, prepuce, mammary glands, peri- or supraorbital region), conjunctivitis, with or without lacrimation, photophobia, serous to mucoid nasal discharge, diarrhea, abortion, ataxia, stiffness of gait, petechial hemorrhages on oral mucous membranes
  • Strains of EAV can cause abortion throughout much of pregnancy (2 months to more than 10 months).
  • In natural outbreaks, abortion rates can vary from < 10% to as high as 60%.
  • Mares that abort from the virus are already pregnant at the time of exposure:
  • This occurs primarily by the respiratory route through direct proximity with an acutely infected animal, frequently sharing the same pasture or having across-the-fence contact.
  • Abortion occurs 1–4 weeks later. Mares exposed very late in gestation may not abort but give birth to a foal congenitally infected with the virus.
  • There is no evidence to indicate that mares that abort from EAV infection are subsequently less fertile.
  • Fever
  • Hives (localized or generalized)
  • Swell portion on skin
  • Damage nodes
  • Pregnancy disturbed
  • You can read more about EVA here


Lesions of EVA virus:

  • The gross and microscopic lesions observed in fatal cases of EVA reflect the extensive and considerable vascular damage caused by the virus; these descriptions are primarily based on experimental infection with the horse-adapted highly pathogenic Bucyrus strain of EAV.
  • The most significant gross findings include edema, congestion, and hemorrhages, especially in the sub-cutis of the limbs and abdomen, excess peritoneal, pleural, and pericardial fluid, and edema and hemorrhage of the intra-abdominal and thoracic lymph nodes and the small and large intestine, especially the cecum and colon.

Gross lesions are usually absent in aborted fetuses, if present, they are limited to an excess of fluid in body cavities and a variable degree of interlobular pulmonary edema.

Pulmonary edema, emphysema, and interstitial pneumonia, enteritis, and infarcts in the spleen have been reported in naturally acquired fatal cases of the disease in foals.


Transmission of EVA virus:

This disease can be transmitted by

  • Through breading (In the case of both types of breading, natural and artificial)
  • Through respiratory secretions
  • Infected stallions shed the virus in semen and can survive as long-term carriers.
  • visit our YouTube channel for for demonstration videos regarding different disease.


Treatment of Equine Viral Arteritis:

Through vaccination, we can prevent the horses.

Horse vaccination for EVA:

  • In North America licensed vaccine is present, this vaccine is modified by a live virus product.
  • It is safe and effective in stallions and non-pregnant mares.
  • Mild post-vaccinal febrile reactions with transient lymphopenia have been observed in a small percentage of first-time vaccinated horses.
  • Like most vaccinations, it does not necessarily prevent viral re-infection and limited viral replication when the horse is exposed to a challenging virus.
  • First-time vaccinates the frequency, duration, and amount of vaccine virus that is shed via the respiratory tract is significantly less than that observed with natural infection.
  • Should shedding occur, it takes place during the first week following vaccination.


Vaccination Schedules for EVA:

  • In planning a vaccination program against EVA, it is important to consult with state and/or federal animal health officials to ensure that any such program complies with the state’s control program for EVA if one exists.
  • It is not possible to differentiate the vaccine-induced antibody response from that due to natural infection.
  • Negative certification is of importance should a vaccinated stallion be considered for export later.
  • Serum from all first-time vaccinates be tested and confirmed negative for antibodies to EAV by a USDA-approved laboratory using virus neutralization.
  • Testing should be performed shortly before the time of vaccination. Mares intended for export should be similarly tested.
  • Annual booster every 12 months and not less than 3 to 4 weeks before breeding.
  • All first-time vaccinated stallions should be isolated for 3 weeks following vaccination before being used for breeding.
  • Maiden and non-pregnant mares may be vaccinated at any time but should be vaccinated not less than 3 weeks before breeding.
  • Mares of unknown vaccination status to be bred to carrier stallions or to be bred with virus-infective semen: Mares to be tested to determine their serological status for EAV antibodies.
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EVA  prevention:

  • Testing all stallions, teasers, and mares before breeding.
  • Take to your vet about vaccination stallions.
  • Isolation
  • Stop breeding if any suspect comes.



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