Survival of H9N2 Avian Influenza Virus in Natural Water Bodies
Bijay Mallick, Arup Sen, Abdul Ahad*
Department of Microbiology and Veterinary Public Health, Chittagong Veterinary and Animal Sciences University (CVASU), Chittagong, Khulshi-4225, Bangladesh.
The present study was conducted to determine the survival period of H9N2 avian influenza virus in natural water bodies at different temperature and time of exposure and to observe the effects of various physiochemical factors on the survival and transmission of this virus via natural water bodies. The study was conducted between October 2015 to January 2016. Influenza virus H9N2 strain was isolated from Bangladesh Livestock Research Institute through Poultry Research and Training Center, Chittagong, Bangladesh. Five ponds water samples were collected from five sub-districts of Chittagong, Bangladesh. The slide haemagglutination test was performed to determine highest possible survival time or infectivity of the H9N2 virus. The findings of this study indicate that water is likely a vital route for the epidemic transmission of avian influenza viruses, especially during the winter season.H9N2 virus can survive up to 4 hours at (22-30˚C) temperature in slightly alkaline pH (7.44 - 7.56) of water, but at 37˚C it can survive hardly for 4 hours. Survival capacity of the H9N2 virus is decreasing with the increasing of environmental temperature and exposure time. Water with high pH value and bicarbonate concentration can reduce survival period of the H9N2 virus. The water samples of this study were soft in nature (<60 PPM). Soft waters may permit the viral persistence, however, the effects of pH and bi-carbonates together concealed the observation of actual effects of the hardness on H9N2 viral survival.