Failure to establish chronic infection of the reproductive tract of the male horse with a South African asinine strain of equine arteritis virus (EAV).

The research article is about an experiment conducted on eight mature horse stallions, which were exposed to a South African strain of Equine Arteritis Virus (EAV), with an aim to study the chronic infection establishment pattern in their reproductive tracts. The results indicate that the reproductive tracts of the stallions did not show a persistent infection.

Research Methodology

• The researchers used eight sexually mature horse stallions for their study.
• They were inoculated intranasally with a South African asinine strain of EAV. This strain of virus was isolated from the semen of a donkey carrier.
• The horses’ physical responses, including fever and other possible clinical signs of equine viral arteritis, were monitored closely.
• They also regularly checked for the presence of the virus in different parts of the horses’ bodies including the nasopharynx, buffy-coat samples, various parts of the reproductive tract, and urine.
• The researchers also closely tracked seroconversion and the associated virus-neutralizing antibody titres in the horses.

Results

• All horses developed fever after being exposed to the virus, with peak temperatures recorded 3-6 days after exposure.
• Six of the horses showed very mild signs of equine viral arteritis while two were asymptomatic.
• The virus was found in the nasopharynxes of six horses 2-7 days post-inoculation, and in the buffy-coat samples of all horses, 2-11 days after inoculation.
• Seroconversion was observed 8 and 10 days post exposure, with peak serum-virus-neutralizing antibody titres marked 14-20 days after exposure.
• Upon euthanising three stallions intermittently 5, 7, and 9 days after exposure, the researchers found the virus presence to be inconsistent in their reproductive tract and urine.
• No virus was identified in the reproductive tract tissues in stallions even on days 16, 23 and 68 after virus exposure.
• When these stallions were bred with six seronegative mares between 13 and 34 days post exposure, no signs of EAV were observed and no seroconversion was detected in any of the mares after breeding. Also, no virus was recovered from semen samples collected at the time of breeding.
• The study concluded that the reproductive tracts tissues of the stallions did not get persistently infected with the South African asinine strain of EAV.