Horse diseases-equine viral arteritis, Biology


Equine viral arteritis


Equine viral arteritis (EVA) is a highly contagious disease of equines and is caused by equine arteritis virus (EAV), a RNA virus belonging to the genus Arterivirus in the family Arteriviridae. The disease is characterized by fever, depression, anorexia, dependent oedema especially of limbs, scrotum and prepuce in stallion, conjunctivitis, urticarial type skin reaction, abortion and rarely pneumonia or pneumoenteritis in young foals. The disease is also known as epizootic lymphangitis or pink eye. No clinical case of EAV infection has been reported from India. However, based on sero- surveillance some seropositive horses have been reported.


Epidemiology:
EAV is sheded in large amount from the acutely infected horses through respiratory route. It is transmitted by direct contact between horses by droplet infection. EVA is transmitted from infected mares through the placenta to their unborn foals. The virus is also excreted in urine and faeces. Infected saliva and nasal discharge  contaminates drinking water, mangers and straw, which are the sources of infection to other healthy horses. Virus is also sheded in semen of acutely infected stallions, some of which become long term carriers and constant semen shedder. The carrier state is found only in stallion and not in the mare. The virus can be transmitted via fresh- cooled or frozen semen used in artificial insemination.


Clinical signs:
There may be fever, swelling (edema) of the legs, scrotum sheath or mammary glands in infected horses. Loss of appetite (anorexia), depression, nasal discharge, initially watery, but becoming mucoids later are also observed in infected animals. The affected horse shows conjunctivitis (pink eye) that may be accompanied by tearing down the face and swelling above or around the eyes. Skin rash (urticaria), often localized to the cheeks or sides of the neck, but sometimes generalized over the body may also occur. Pneumonia or pneumonia with enteritis in very young foals is common. EVA causes contagious respiratory disease in horses and abortion in mares. A mild stomatitis may also be seen. Oedema of the ventral body wall, limbs extending up to prepuce of the stallion may be seen. Abortion due to EVA infection occurs late in the acute phase or early in the recovery phase of the infection, not months after the virus exposure has taken place.


Diagnosis: Diagnosis of abortion due to EAV is largely dependent on virus isolation from placenta or foetal tissues in RK13, horse kidney, Vero and BHK-21 cell lines. Serial 2-8 blind passages are required. Virus-specific antibody in serum of horses can be demonstrated by complement fixation (CF) and virus neutralization (VN) tests.


Prevention and control: Modified live virus vaccine is available that gives strong immunity. An inactivated vaccine developed in Japan has been reported to induce neutralizing antibodies and preventive to virus shedding through semen. Serum samples for EVA testing should be collected from all horses before breeding and virus isolation should be performed on imported semen before use.

Posted Date: 9/18/2012 7:58:49 AM | Location : United States







Related Discussions:- Horse diseases-equine viral arteritis, Assignment Help, Ask Question on Horse diseases-equine viral arteritis, Get Answer, Expert's Help, Horse diseases-equine viral arteritis Discussions

Write discussion on Horse diseases-equine viral arteritis
Your posts are moderated
Related Questions
Munch Pressure Flow Model Munch, a German plant physiologist, proposed in 1930, a simple physical model which can be tested in the laboratory for the mechanism of phloem trans

NERV E FIBRES - Axon or dendrite of a nerve cell covered with one, two or three sheaths is called nerve fibre. Dendrites are surrounded only by one sheath. An axon may b

Name the sac-like, blind pouch of large intestine, situated below the level of junction of the small intestine into the side of large intestine. At the lower portion of this pouch

Procedure for testing Presence of Vanaspati and Rancidity in Ghee? Carry out the steps enumerated herewith for conducting this exercise. For Vanaspati Checking: 1. Take 5

Regulation of HMP Pathway The following factors play an important role in regulation of HMP pathway: a)  The first  reaction of this pathway catalysed by glucose-6-phosphate

Life cycle of sporozoans The complex life cycle of sporozoans typically involves an asexual and a sexual phase. Sporozoans are haploid except for the zygote. The zygote underg

what are the organs of respiration in the lower form of animals?

In earthworms, when the ovaries mature, the clitellum secretes a viscous substance in the form of a girdle. This girdle hardens in to a cocoon around the clitellum. The ova are dis

Identify the hormones produced by the anterior and posterior lobes of the pituitary gland and specify the functions of those hormones.

When a fatty acid reacts with glycerol, the result is- Select one: a. Formation of an amide b. Formation of an ester c. Formation of hydrocarbon d. Formation of a th