Sampling Strategies and Biodiversity of Influenza A Subtypes in Wild Birds

Abstract

Wild aquatic birds are recognized as the natural reservoir of avian influenza A viruses (AIV), but across high and low pathogenic AIV strains, scientists have yet to rigorously identify most competent hosts for the various subtypes. We examined 11,870 GenBank records to provide a baseline inventory and insight into patterns of global AIV subtype diversity and richness. Further, we conducted an extensive literature review and communicated directly with scientists to accumulate data from 50 non-overlapping studies and over 250,000 birds to assess the status of historic sampling effort. We then built virus subtype sample-based accumulation curves to better estimate sample size targets that capture a specific percentage of virus subtype richness at seven sampling locations. Our study identifies a sampling methodology that will detect an estimated 75% of circulating virus subtypes from a targeted bird population and outlines future surveillance and research priorities that are needed to explore the influence of host and virus biodiversity on emergence and transmission.

Genetic characterization of a rare H12N3 avian influenza virus isolated from a green-winged teal in Japan

“…2) indicated that the H12 HA gene first reassorted with an unsampled NA subtype between 1997 and 2003, and the resultant virus reassorted with an H1N3 virus between 2006 and 2009, giving rise to the H12N3 subtype. Given the promiscuity of H12 and N3 with other NA and HA subtypes respectively [26], we believe this to be a plausible explanation for this virus' emergence. However, owing to the limited number of H12N3 sequences available in the public database, the definitive conclusions on reassortment are difficult to ascertain.…”

Global Avian Influenza Surveillance in Wild Birds: A Strategy to Capture Viral Diversity

“…Rather, resource allocation could be prioritized to provide sustained surveillance in a few targeted locations and in specific seasons that maximize information on viral diversity relevant to potential spread (e.g., high-risk species, species interfaces, major staging and migration stopover sites, and reassortment hotspots [ 23 ]). Recent analysis of avian influenza virus subtype diversity and richness suggests that 75% of HA and NA subtype diversity in wild birds could be captured through targeted surveillance efforts in the Northern Hemisphere over a 4-year period ( 24 ). …”

“…Although we propose an initial focus on the Northern Hemisphere to leverage current investments and target surveillance on the basis of prior avian influenza study findings reported above ( 24 , 25 ), we do not intend to undermine the role of efforts elsewhere. We especially acknowledge that bias in surveillance effort has limited current knowledge on avian influenza virus diversity in the Southern Hemisphere ( 4 ).…”

Vaccination against infectious diseases: What is promising?

“…A lot of them are sporadically transmitted to other birds, in particular to chickens, causing outbreaks of fowl pest. Where contacts of fowl and humans are close like in China and South-East Asia, direct transmission to humans happens usually causing severe respiratory disease, by which the public health services are alerted and instant measures are taken to prevent an epidemic [27,28]. Concerning these cases, a lot of new research on influenza pathogenicity was done [29][30][31][32].…”