Kinetics of Equid herpesvirus type 2 infections in a group of Thoroughbred foals.

The study investigates the progression and impact of Equid herpesvirus type 2 (EHV-2), a virus often found in horses, and its potential role in causing pneumonia caused by Rhodococcus equi in foals. The use of least 43 soals over 10 months with continual blood sampling shows that the majority of the foals were infected within the first two months and majority remained positive of infection throughout.

Objectives of the Study

• The primary objective of the research was to determine the kinetics, or the rates of reaction and behavioral patterns, of Equid herpesvirus type 2 (EHV-2) infection in Thoroughbred foals.
• The study also aimed at determining whether there was a relationship between EHV-2 infection and the development of Rhodococcus equi pneumonia in these animals.

Methodology

• The researchers monitored a group of 43 foals over a 10-month period by collecting serial blood samples.
• The viral load of EHV-2, or the amount of virus present in the blood, was determined using a quantitative real-time Polymerase Chain Reaction (PCR) assay.

Findings

• The researchers found that all but two foals had tested positive for EHV-2 at least once during the study period, with the majority (88%) of the foals becoming infected within the first two months of life.
• Most foals remained positive for EHV-2 in all subsequent samples, indicating a persistent presence of the virus in the infected animals.
• They also found that the viral load varied among individual foals and between different sampling times for each foal.
• Significantly higher EHV-2 load was observed in 2-month-old foals suspected of R. equi pneumonia as compared to healthy foals of the same age. This difference was not observed in foals of other ages.

Conclusion

• The research adds to our understanding of EHV-2 epidemiology in foals, by noting its widespread presence and potential role in predisposing the young animals to secondary infections like R. equi pneumonia.