spiratory tract of horses , characterized by coughing and nasal discharge . The importance of the disease is the large numbers of animals that can be affected in the outbreak , especially when horses are congregated in colder months . Fatalities in uncomplicated cases are unlikely , but affected animals are unable to work , racehorses have to break their training , and ‘ storms ’ of abortions occur in bands of brood mares , with as many as 80-85 % of mares at risk either aborting or losing their foals during their first day of life .
Nervous system involvement can occur in an outbreak in which abortion and respiratory problems also are present . Outbreaks may be massive . It is most common in horses that become reinfected with the virus . The standard killed vaccine is not preventative but aids in the horse developing a certain level of immunity . There are modified-live vaccines available designed to aid in the prevention of abortion . The vaccine is designed to be administered at 5 , 7 , and 9 months of gestation .
The ataxia and paresis lasts for up to several weeks and is followed by recumbency . Some die after an illness of only 2 days . In a majority of cases , the patient has to be euthanized within a month . There have been reports of 50-60 % of horses exposed to the respiratory form of the disease developed nervous signs . The disease can be reproduced experimentally and is characterized by an incubation period of 7 days .
As an upper respiratory tract infection it must be differentiated from strangles , with nasal discharge and swollen lymph nodes , from the more severe equine viral arteritis and equine influenza . It may also be confused with purpura hemorrhagica in which subcutaneous swelling of the legs is severe .
There is no specific treatment that is likely to modify the action of the virus but it is usual to administer antibiotics to horses with equine viral rhinopneumonitis to prevent and treat infection with secondary bacterial invaders . The treatment should be continued over 4-6 days . Warm , draftfree , isolated confinement should be provided if possible , with laxative foods and a constant supply of fresh drinking water .
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MARCH 2018 PARKER COUNTY TODAY
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