WHO says H1N1 virus could mutate, warns vigilance in watching for symptoms

Geneva, Switzerland

-- Concerned by the potential of the H1N1 pandemic virus to become more virulent as the pool of viral genes circulates among a number of hosts, the World Health Organization (WHO) is calling for close monitoring and proper management of animals that exhibit symptoms of respiratory infections.

The WHO is on guard for viral changes, especially after detecting a novel H3N2 influenza virus affecting mink on a farm in Denmark. No humans have been infected with that H3N2 virus, but a WHO spokesperson says the incident demonstrates "the constantly evolving ecology of influenza viruses, the potential for surprising changes, and the need for constant vigilance."

The WHO also is asking that samples from infected animals and humans be taken for full genome sequencing of the virus to look for mutations that could affect virulence, host range, or antiviral resistance.

Aside from swine, the only animals reported to be infected with H1N1 so far are turkeys in Chile and Canada, and a cat and two ferrets in the United States.