Equine Rhinopneumonitis (EHV-1) - Essay Example

Equine Rhinopneumonitis (EHV EHV-I also known as Equine Herpesvirus Type I is an endemic disease in the United s and is a serious disorder which causes acute respiratory disease, abortion, neurological disorders and death. It is caused by equid herpesvirus-1. Another related infection occurs with EHV-4, which was initially thought to be a subtype of EHV1, but later identified as belonging to an antigenically distinct group (merckvetmanual.com). They belong to a family of alphaherpesviruses of horses (www.oie.int).

It is a terrible disease much feared by horse breeders and can have a great economic impact (ag.udel.edu). Respiratory symptoms are the most common manifestation in young horses but the outbreaks reported in many areas are usually due to the neurologic form. Frequent outbreaks of the respiratory form occur in young foals in areas where concentrated populations exist.The disease is highly contagious and spreads by the aerosol route through the inhalation of virus laden respiratory secretions. Horses under three years of age are particularly susceptible and the virus quickly spreads and multiplies in the respiratory epithelium.

2-8days post exposure, symptoms of depression; inappetance, nasal discharge and fever are manifested (www.oie.int). Laboratory examination reveals neutropenia and lymphopenia with serous nasal discharge, pharyngitis, malaise, cough and inflammation of lymph nodes. Foals suffering from EHV1 show diphasic fever patterns (merckvetmanual.com). If complications of secondary bacterial infection don’t occur, the disease is usually followed by complete recovery after 1-2 weeks but causes substantial distress to animals which affect their training and racing schedules.

Abortions occur in infected pregnant mares 2-12 weeks after initial exposure to the virus. This usually happens between the 7-11th month of gestation (merckvetmanual.com). Aborted fetuses appear fresh with minimal autolysis unlike abortions with EVA (Equine Viral Arteritis). There is no damage to the reproductive tract of the mares and they usually recoup to attain normal conception ability after recovery. Outbreaks with neurological symptoms result in symptoms which may range from mild incoordination to posterior paralysis with the animals assuming recumbent positions.

There is a loss of bladder control and tail function. Paralysis in its severest form can result in quadriplegia with eventual death.It is difficult to make distinction from clinical symptoms between EHV1, Equine Influenza and EVA. Virus isolation from nasopharyngeal swabs, serum and whole blood is the only method of diagnosis. Viral antigen can be detected from fetal tissue, lungs, liver, adrenal glands and lymphoreticular tissues (merckvetmanual.com). ELISA, PCR are some of the techniques employed for confirmatory diagnosis (www.oie.int).

Treatment is symptomatic and usually aimed at preventing secondary bacterial infections. Rest and nursing are recommended for the suffering animals. In disease with neurologic symptoms, complete recovery is possible if recumbence exists for only 2-3 days.Strict quarantine of suspected and diagnosed cases is recommended to prevent the spread of infection. Biosecurity measures should be practiced in endemic areas during the season when the disease is more prevalent (www.aphis.usda.gov). Vaccines of many strains are available either for EHV (respiratory form) alone or in combination with other diseases.

However they are recommended for use in some countries while banned in others. This is because the available vaccines don’t cover all strains and there is likelihood of infection with anew strain despite vaccination. If vaccination is practiced, it should be administered at 3-4 months age in young foals with a booster dose 4-8 weeks later. Works CitedEquine Herpesvirus Infection, online information available at: http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/121302.htm&word=EHV%2c1 Equine Rhinopneumonitis, Chapter 2.5.7, Available at: http://www.oie.int/eng/normes/mmanual/A_00085.

htm Equine Herpes Virus Infection, Online article available at: http://ag.udel.edu/anfs/faculty/documents/EquineHerpesVirusInfection-January2006.pdf Questions and Answers: Equine Herpesvirus, Factsheet, available online at: http://www.aphis.usda.gov/publications/animal_health/content/printable_version/faq_equine_herpesvirus.pdf