A national study of individuals who handle migratory birds for evidence of avian and swine-origin influenza virus infections

Abstract

Background Persons with occupational or recreational exposure to migratory birds may be at risk for infection with highly pathogenic avian influenza and other avian influenza viruses since wild birds are the natural reservoir of influenza A. Additionally, bird handlers may host avian and swine-origin influenza (pH1N1) virus co-infections, which generate reassortant viruses with high pathogenicity in mammals. Objectives We assessed the prevalence of avian and swine influenza viruses in US-based bird handlers and estimated their exposure to different orders of wild birds including waterfowl (Anseriformes), songbirds (Passeriformes), and shorebirds (Charadriiformes). Study Design Cross-sectional serologic survey accompanied by a questionnaire to estimate behavioral risk factors. This is first survey of US-based bird handlers who also work at international sites. Results 401 participants were recruited and tested over the course of three years. One participant with occupational exposure to migratory birds had evidence of past infections with a H5N2 virus antigenically related to A/Nopi/MN/07/462960-02, which is the first case of this influenza subtype in a human host associated with exposure to wild rather than domestic birds. We detected no avian and swine-origin influenza virus co-infections. The exposure of bird handlers to songbirds was four times greater than to shorebirds or waterfowl. Conclusions Though rare, the transmission of avian influenza viruses from migratory birds to US-based bird handlers has potentially significant public health and economic consequences.

Risk of Human Infections With Highly Pathogenic H5N2 and Low Pathogenic H7N1 Avian Influenza Strains During Outbreaks in Ostriches in South Africa

“…A serosurvey conducted after the epizootic outbreak caused by (HPAI)H7N7 in the Netherlands in 2003 identified antibodies in approximately half of exposed individuals and household contacts of infected persons [5, 36]. H5N2 transmission has been reported from poultry and wild birds to humans in Japan and the United States, respectively, although no symptoms were recorded [37, 38]. …”

Appendix 1: Evidence Review on Occupational Exposure of Swine and Poultry Workers

“…[11][12][13][14][15][16][17] eighteen articles assessed commercial poultry workers, seven articles assessed non-commercial poultry workers (i.e. backyard farmers), and four studies assessed other workers including bird banders, 18 handlers of migratory birds, 19 firefighters, 11 and government workers 11 involving in culling.…”

Characterization of Novel Reassortant Influenza A (H5N2) Viruses Isolated from Poultry in Eastern China, 2015

“…Previous studies showed that people who are in frequent contact with infected animals can be infected by the H5N2 viruses (Ogata et al, 2008; Yamazaki et al, 2009; Shafir et al, 2012; Wu et al, 2014c). A large number of novel HPAI H5 virus infections have occurred in the human population and a lack of pre-existing immunity to H5 AIVs poses a potential public health risk.…”