Flu season for horses can be any season. And considering that even horses vaccinated against the equine influenza virus (EIV) can still “catch the flu,” this disease is cause for concern. A group of Japanese researchers, however, recently evaluated a flu inhibitor in horses and found that it could help EIV-infected animals recover more quickly.

“The flu, caused by EIV, is one of the most important respiratory diseases in horses,” said Takashi Yamanaka from the Epizootic Research Center at the Equine Research Institute, operated by the Japan Racing Association. EIV is highly contagious; causes fever, nasal discharge, depression, anorexia, and coughing; and can lead to fatal pneumonia. Affected horses require time off from training and performing to receive treatment and recover. What’s worse, influenza outbreaks occur even in vaccinated horses due to the fact that the vaccine is not 100% effective against all “field” strains of EIV.

Researchers have tested several EIV inhibitors in horses, but those tested required oral administration several times per day or needed to be inhaled. Neither approach is overly practical for horses and owners. But Yamanaka recently took a look at a human flu inhibitor for possible use in horses.

“Peramivir is a pharmaceutical drug that inhibits one of the key enzymes, neuraminidase (NA), on the influenza virus,” explained Yamanaka. "Peramivir (has been) licensed for use in humans since 2010