New influenza A virus reaches dogs

A new dog flu virus that has killed some racing greyhounds has made the unusual jump from horses to dogs and may threaten pets, but 'there is no evidence that it can infect people,' said Dr. Ruben Donis of the US Centers for Disease Control and Prevention, who has published a report on the new influenza A virus in the journal 'Science'.

However, the report went on to add that 'evidence of canine influenza infection in pet dogs, a primary companion animal for humans, raises the possibility that dogs may provide a new source for transmission of novel influenza A viruses to humans'.

Studies of the virus, called H3N8, could have important implications for understanding the H5N1 avian flu virus, which has now killed 65 people in Asia since late 2003.

'We must keep in mind that this H3N8 equine influenza virus has been in horses for over 40 years. In all these years we have never been able to document a single case of human infection with this virus,' Donis added, before stating that the virus could be controlled with antiviral drugs.

'This virus can cause a respiratory disease that mimics a syndrome that we call kennel cough,' said Dr. Cynda Crawford of the University of Florida College of Veterinary Medicine, who first discovered the virus in greyhounds. 'But despite the rumours that are out on the Internet, it is not as deadly as people want to make out. Nearly all dogs are susceptible to infection, and about 80% will have a mild form of disease, characterized by cough and some nasal discharge that will resolve. It seems to have a mortality rate of 5-8%.'

She believes that it has managed to jump species because of changes in just a few of the amino acid building blocks of proteins.