Transboundary Emerging and Exotic Animal Disease/ Exotic Animal Disease Practice Exam

Which species is thought to have first transmitted the H3N2 influenza virus to dogs?

1. Cats

2. Horses

3. Avian species

4. Wild rodents

The correct answer is: Avian species

The H3N2 influenza virus, known for causing respiratory illness in dogs, is thought to have originated from avian species. This lineage of the virus is closely linked to the transmission dynamics observed in wild birds, which frequently harbor various strains of influenza. Birds can carry these viruses without showing symptoms, and they are an important reservoir for influenza viruses. It is through direct or indirect contact with infected avian species that the H3N2 virus was able to adapt and jump species to dogs, leading to outbreaks of canine influenza. This transmission pathway highlights the role of birds in the emergence of certain influenza viruses in terrestrial animals, particularly in domesticated and companion species like dogs. The other options do not serve as the recognized source for the introduction of H3N2 into the canine population. While cats, horses, and wild rodents may have their own interactions with influenza viruses, they are not implicated in the specific transmission route of H3N2 to dogs.