EQUINE INFLUENZA IN DOGS
In the UK there have been two confirmed outbreaks of H3N8 equine influenza in foxhounds, retrospectively diagnosed by the AHT. The cases occurred between 2002-2003, when there were large numbers of horses infected with equine influenza across the UK.
It is likely that the hounds contracted equine influenza from infected horses when they travelled together in close proximity in a horse lorry. The enclosed airspace of the lorry would have provided ideal conditions for the virus to be transmitted from the horses to the hounds.
Equine influenza has also been diagnosed in dogs in Australia following the large outbreak in horses in 2007. Most of those horses had no protection and could therefore shed large quantities of virus. Dogs kept in close contact with infected horses seroconverted to equine influenza.
In the USA equine influenza has also infected dogs, but with a very different outcome. In 2004 greyhounds in Florida first showed signs of acute respiratory disease, with a 10% mortality rate. The disease spread rapidly between states and has now adapted to transmit efficiently in the dog. H3N8 canine influenza has not been reported anywhere outside the US, despite being present in the country for several years.
Clinical signs include:
• Persistent harsh cough (despite treatment with antibiotics)
• Nasal discharge
• Increased respiratory rate and effort
• Rapid spread within a group of dogs
These signs usually appear two to five days after exposure to the virus. As canine influenza has not been diagnosed in the UK, there is no vaccine available for it.
At the AHT we are able to screen for equine influenza (and canine influenza) in dogs as part of our panel of canine respiratory diseases, or as individual tests. Please see our canine respiratory panel for more details.