# 2960
Robert Roos, News Editor of CIDRAP (Center for Infectious Disease Research & Policy), has an excellent overview of a new paper that has recently come out in The Archives of Virology, by Takano R, Nidom CA, Kiso M, et al. entitled A comparison of the pathogenicity of avian and swine H5N1 influenza viruses in Indonesia.
Roos also interviews Richard Webby, PhD, a virologist and flu researcher at St. Jude Children’s Research Hospital in Memphis, about this paper.
Highly recommended that you follow the links and read this review in its entirety.
H5N1 virus may be adapting to pigs in Indonesia
Robert Roos
News Editor
Mar 31, 2009 (CIDRAP News) – Scientists report that H5N1 avian influenza viruses may be adapting to pigs, as evidenced by the finding that H5N1 viruses isolated from pigs in Indonesia were less harmful to mice than were H5N1 viruses from chickens.
The finding suggests that in growing in pigs, the virus may have become less harmful to mammals in general, the authors report. That sounds reassuring, but the authors say it may mean the virus is one step closer to turning into a human pandemic strain.
In the study, scientists from Japan and Indonesia collected viruses from chickens and pigs in Indonesia, grew them in laboratory cell cultures, and used them to infect mice. They found that the viruses from pigs were less lethal to mice than the viruses from chickens, according to their recent report in the Archives of Virology.
"We found that swine isolates were less virulent to mice than avian isolates, suggesting that the viruses became attenuated during their replication in pigs," the report states.
An intermediate host
Pigs are seen as a possible intermediate host that can help avian flu viruses adapt to humans, because the epithelial cells in pigs' trachea can be infected by both avian and human flu viruses, the article notes. If avian and human viruses infected a pig at the same time, they could mix or reassort, giving rise to a novel strain that might be able to spread in humans. The flu pandemics of 1957-58 and 1968-69 were caused by avian-human hybrid viruses, though it is not known if they arose in pigs.
