Pulmonary ultrasonographic abnormalities associated with naturally occurring equine influenza virus infection in standardbred racehorses.

This research aims to study whether the equine influenza virus, a cause of acute respiratory disease (IRD) in horses, leads to any identifiable abnormalities in pulmonary and pleural areas through the use of ultrasonography. The study discovered that horses infected with the virus showed signs of mild lung consolidation and peripheral pulmonary irregularities, suggesting that equine influenza can indeed impact the lower respiratory tract of these animals.

Research Procedure

• The study involved an evaluation of Standardbred racehorses manifesting signs of Infectious Respiratory Disease (IRD). IRD was defined by symptoms like acute coughing and mucopurulent nasal discharge.
• The research included 16 horses with IRD, and each of these horses was compared with either one or two horses sharing the same owner or trainer but showing no signs of IRD, amounting to a total of 30 control horses.
• Thoracic ultrasonography was performed on horses suffering from IRD within 5-10 days from the onset of the disease. The horses free from IRD were examined at the same time, setting a comparative context.

Findings

• Equine influenza virus was established as the main causal agent leading to IRD in the horses under study.
• Mild lung consolidation and peripheral pulmonary irregularities were observed more frequently in the horses suffering from IRD. These abnormalities were seen in 69% of the diseased horses, versus 37% of the control group.
• The median scores for lung consolidation and peripheral irregularities were higher in infected horses than in uninfected ones.
• No pleural effusion was observed in any of the horses in the study.

Conclusions

• The study concludes that equine influenza virus infection can lead to noticeable abnormalities in the equine lower respiratory tract, specifically lung consolidation and peripheral pulmonary irregularities. These were more common in horses showing clinical signs of IRD.
• Given the mild nature of the observed IRD effects, further research is recommended to explore the clinical significance of the detected ultrasonographic abnormalities.