Research On The Outbreak Transmission And Evolution Of H5 Highly Pathogenic Avian Influenza Virus

Since 1996,H5 Highly Pathogenic Avian Influenza Virus(HPAIV)has been transmitted all over the world and continued to rapidly evolve.It became a disaster for the poultry industry and a threat for wild birds and mammals.To control and prevent the disease,it’s important to study understanding its outbreaks,spread and evolution.This study aimed to study the outbreaks,spread and evolution of H5 HPAIV,and figure out how the behavior of hosts and geographic environment influence the outbreaks and evolution of H5 HPAI.It will provide provide suggestions and theoretical support for the prevent and control of avian influenza.The major findings are as follows:(1)We studied the H5 HPAIV outbreaks from 2004 to 2015,and found that there are twice geographical dispersion,one is from 2005 to 2008 with one virus subtype(H5N1),and one is from 2014 to 2015 with many subtypes such as H5N2,H5N1,and H5N8.Besides,the genetic distance in different regions showed that in some regions,such as China,the local persistent viruses and different hosts might lead to the variation of genetic distance;and in some regions,such as South Asia and North America,the geographic isolation might contribute to the insignificant difference of viruses.(2)We used the H5N1 HPAIV outbreaks and gene sequence data spanning 2005 to 2013.We studied the spread of viruses isolated from different hosts in a phylogeographic perspective.The reconstruction of virus circulation resulted in a varied migration network of H5N1 virus in different hosts.We inferred that the long distance dispersal pattern of H5N1 virus followed that of bird migration,while short distance spread might follow local networks such as poultry rising and transportation patterns.(3)We studied the distribution of stopover sites of the Bar-headed Goose and Ruddy Shelduckusing Generalized liner mixed model based on normalized difference vegetation index(NDVI),geographic data,and satellite tracking of migratory birds.We found that Bar-headed Geese are colonial breeders,which can facilitate spread of avian influenza within and possibly among populations.The Ruddy Shelducks migrate individually and their stopover sites are widely distributed,increasing the potential for Ruddy Shelducks expose viruses to more environments and potential species.