Equine Viral Rhinopneumonitis in horses

Horses October 14, 2014 Print Friendly and PDF

Ashley Griffin, University of Kentucky

Equine viral rhinopneumonitis (EVR) produces an acute respiratory catarrh, which is inflammation due to excessive discharge or buildup of mucus in the throat and nose. The Type I strain of EVR is the most common virus found in horses. Transmission of EVR occurs with direct or indirect contact with virus-laden nasal discharge, aborted fetus, or placenta. 

Clinical Signs


1. congestion and clear nasal discharge
2. mild to server ataxia or paresis (slight of incomplete paralysis) of hind quarters
3. fever for two to three days
4. cough
5. abortion after three to 12 weeks of exposure and most commonly in the eighth to 11th month of gestation.




Treatment consists of isolating infected horses and initiating good sanitary and hygiene management.




Annual vaccinations and good sanitary practices provide the best preventive treatment.


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This work is supported by the USDA National Institute of Food and Agriculture, New Technologies for Ag Extension project.