Search

Cross-species infections with influenza A viruses readily occur between humans and pigs. Pigs often have been infected by human epidemic viruses (1), and swine workers and their family members are [...]

Objectives The zoonotic potential of H3N8 canine influenza virus ( CIV) has not been previously examined; yet considering the popularity of dogs as a companion animal and the zoonotic capabilities of other influenza viruses, the public health implications are great. This study aimed to determine the seroprevalence of antibodies against CIV among a US cohort. Design A cross-sectional seroepidemiological study was conducted between 2007 and 2010. Setting Recruitments primarily occurred in Iowa and Florida. Participants were enrolled at dog shows, or at their home or place of employment. Sample Three hundred and four adults occupationally exposed to dogs and 101 non-canine-exposed participants completed a questionnaire and provided a blood sample. Main outcome measures Microneutralization and neuraminidase inhibition assays were performed to detect human sera antibodies against A/Canine/Iowa/13628/2005(H3N8). An enzyme-linked lectin assay ( ELLA) was adapted to detect antibodies against a recombinant N8 neuraminidase protein from A/Equine/Pennsylvania/1/2007(H3N8). Results For all assays, no significant difference in detectable antibodies was observed when comparing the canine-exposed subjects to the non-canine-exposed subjects. Conclusion While these results do not provide evidence for cross-species CIV transmission, influenza is predictably unpredictable. People frequently exposed to ill dogs should continually be monitored for novel zoonotic CIV infections. [ABSTRACT FROM AUTHOR]

Background Equine influenza virus ( EIV) epizootics affect 2·1 million Mongolian horses approximately every 10 years and critically impact economy and nomadic livelihood of Mongolia. Objectives An active surveillance program was established in 2011 to monitor influenza viruses circulating among Mongolian horses. Methods Nasal swabs were collected from horses in free-ranging horse herds in Töv, Khentii, and Dundgovi aimags (provinces) from January to September 2011. Real-time reversetranscriptase-polymerase chain reaction ( rRT- PCR) was used to determine the presence of influenza A virus. Influenza A-positive specimens were cultured to amplify virus; viral RNA was extracted, and gene segments were amplified and sequenced by Sanger sequencing. Results A total of 745 horses were swabbed; most horses were without clinical signs of illness. In July 2011, reports of influenza-like illnesses emerged among horses in Mongolia's capital, and subsequently, surveillance efforts were adjusted to swab horses associated with the epizootic. Thirty-four specimens of rRT- PCR influenza-positive virus were collected in May, June, August, and September. Three specimens yielded detectable virus. Gene sequence studies suggested that all three isolates were identical H3 N8 viruses. Phylogenetic analyses indicated the strain was very similar to other H3 N8 EIVs circulating in central Asia between 2007 and 2008. Conclusions As large Mongolian equine herds often seem to suffer from EIV epizootics, it seems prudent to continue such routine equine influenza surveillance. Doing so will provide an early warning system, should novel viruses emerge, help in assessing if EIV is crossing over to infect humans and provide data to assess the likely effectiveness of current EIV vaccines. [ABSTRACT FROM AUTHOR]

Background. Regions of Thailand reported sporadic outbreaks of A/H5N1 highly pathogenic avian influenza (HPAI) among poultry between 2004 and 2008. Kamphaeng Phet Province, in north-central Thailand had over 50 HPAI poultry outbreaks in 2004 alone, and 1 confirmed and 2 likely other human HPAI infections between 2004 and 2006. Methods. In 2008, we enrolled a cohort of 800 rural Thai adults living in 8 sites within Kamphaeng Phet Province in a prospective study of zoonotic influenza transmission. We studied participants' sera with serologic assays against 16 avian, 2 swine, and 8 human influenza viruses. Results. Among participants (mean age 49.6 years and 58% female) 65% reported lifetime poultry exposure of at least 30 consecutive minutes. Enrollees had elevated antibodies by microneutralization assay against 3 avian viruses: A/Hong Kong/1073/1999(H9N2), A/Thailand/676/2005(H5N1), and A/Thailand/384/2006(H5N1). Bivariate risk factor modeling demonstrated that male gender, lack of an indoor water source, and tobacco use were associated with elevated titers against avian H9N2 virus. Multivariate modeling suggested that increasing age, lack of an indoor water source, and chronic breathing problems were associated with infection with 1 or both HPAI H5N1 strains. Poultry exposure was not associated with positive serologic findings. Conclusions. These data suggest that people in rural central Thailand may have experienced subclinical avian influenza infections as a result of yet unidentified environmental exposures. Lack of an indoor water source may play a role in transmission. [ABSTRACT FROM AUTHOR]