Infection of dogs with equine influenza virus: evidence for transmission from horses during the Australian outbreak.

The research article discusses a study on the transmission of equine influenza virus from infected horses to dogs during an outbreak. The study suggested that dogs in close proximity to infected horses were more likely to contract the virus, but found no evidence of the virus being transmitted amongst dogs themselves.

Initial Observations and Tests

• During the outbreak of equine influenza (EI), veterinary professionals reported respiratory disease in dogs that were in close proximity to the infected horses. This led researchers to conduct a research study to investigate a potentialspread of the equine influenza virus to dogs.
• The first step in the study was testing for the influenza virus in dogs. The researchers used the influenza A/Sydney/2007 virus as the test antigen for this experiment because it is a common substrain of the virus. 23 dogs out of the total tested were found to be seropositive, implying the presence of the virus in them.

Clinical Signs and Transmission

• Among the seropositive dogs, 10 exhibited clinical signs of the illness, signalling an active virus transmission from infected horses to these dogs. The clinical symptoms likely include respiratory distress, similar to the symptoms displayed by human patients of influenza.
• The study found that the EI virus appears to be easily transmitted to dogs that were held in close proximity to infected horses. This is a significant finding as it suggests the possibility of cross-species transmission of the virus, a trait shared by many of the most deadly viruses including influenza.

Absence of Lateral Transmission

• Despite the apparent transmission of the virus from horses to dogs, the researchers found no evidence of lateral transmission among the dogs. This indicates that dogs that were infected by equine influenza did not spread the virus to other dogs that were not in close contact with infected horses.
• This absence of lateral transmission among dogs suggests that while dogs may contract the virus from close proximity to infected horses, they are unlikely to be a significant vector in the spread of equine influenza. It has important implications for quarantine and disease control measures during outbreaks.