Friday, March 09, 2012

WHO: Human Risk From H5N2 Is Low


Photo Credit – FAO


# 6212



In Taiwan there’s a huge row going on over the alleged cover-up by some government officials of highly pathogenic H5N2 infections in that nation’s poultry (see AsiaOne news Taiwan agency intentionally delays action on H5N2: Recording).


H5N2, while an avian influenza virus, is currently considered a far less dangerous pathogen than its infamous cousin, H5N1.


But all H5 viruses (along with H7s) are reportable to the OIE because of their potential to evolve into more dangerous viruses, particularly when they are allowed to proliferate in large flocks of poultry.


Understandably, there is some public concern in Taiwan now that it appears that some H5N2 infected poultry may have made it into the food chain.


Today, Gregory Hartl, spokesperson for the WHO’s  Global Global Alert and Response Network, is quoted by the Focus Taiwan News Channel offering some reassurance on the public health threat of the virus.



Little chance of H5N2 affecting humans: WHO

2012/03/09 13:20:38

Brussels, March 8 (CNA) A World Health Organization (WHO) official said Thursday that there have been no confirmed cases of avian flu virus H5N2 affecting humans, and the possibility of it seriously affecting human health like the more virulent H5N1 has done is low.


Gregory Hartl, spokesman for the WHO's Global Alert and Response Network, told CNA that H5N2 is one of many avian flu viruses and is unpredictable, but so far there have been no confirmed cases of H5N2 avian virus in humans.

(Continue . . .)


Hartl goes on to say that there may have been some undetected human infections with the H5N2 virus, and that it could someday become a more serious health threat, but for now the risk from the virus is low.



Those with long memories will recall that are a small number of seroprevalence studies that have found elevated H5N2 antibody titers – particularly among poultry workers.


J Epidemiol. 2008;18(4):160-6. Epub 2008 Jul 7.

Human H5N2 avian influenza infection in Japan and the factors associated with high H5N2-neutralizing antibody titer.

Ogata T, Yamazaki Y, Okabe N, Nakamura Y, Tashiro M, Nagata N, Itamura S, Yasui Y, Nakashima K, Doi M, Izumi Y, Fujieda T, Yamato S, Kawada Y.

Arch Virol. 2009;154(3):421-7. Epub 2009 Feb 3.

Serological survey of avian H5N2-subtype influenza virus infections in human populations.

Yamazaki Y, Doy M, Okabe N, Yasui Y, Nakashima K, Fujieda T, Yamato S, Kawata Y, Ogata T.



While suggestive of (possibly sub-clinical) prior H5N2 infection (note: other factors might be associated antibody positivity), there is precious little evidence to link any significant or serious human illness to the H5N2 virus.


That, as Gregory Hartl points out, could change over time.


Which is why the OIE, FAO, and the World Health Organization view outbreaks of avian influenza in poultry seriously – even when it isn’t the dreaded H5N1 virus.