Surveillance of avian influenza viruses from 2009 to 2013 in South Korea

Abstract

Avian influenza viruses (AIVs) are carried by wild migratory waterfowl across migratory flyways. To determine the strains of circulating AIVs that may pose a risk to poultry and humans, regular surveillance studies must be performed. Here, we report the surveillance of circulating AIVs in South Korea during the winter seasons of 2009–2013. A total of 126 AIVs were isolated from 7942 fecal samples from wild migratory birds, with a total isolation rate of 1.59%. H1‒H7 and H9‒H11 hemagglutinin (HA) subtypes, and N1‒N3, N5, and N7‒N9 neuraminidase (NA) subtypes were successfully isolated, with H6 and N2 as the most predominant HA and NA subtypes, respectively. Sequence identity search showed that the HA and NA genes of the isolates were highly similar to those of low-pathogenicity influenza strains from the East Asian-Australasian flyway. No match was found for the HA genes of high-pathogenicity influenza strains. Thus, the AIV strains circulating in wild migratory birds from 2009 to 2013 in South Korea likely had low pathogenicity. Continuous surveillance studies such as this one must be performed to identify potential precursors of influenza viruses that may threaten animal and human health.

Surveillance of avian influenza viruses from 2014 to 2018 in South Korea

“…Similar to our previous report on avian influenza surveillance from 2009 to 2013 in South Korea 14 , percent IAV-positivity of bird fecal samples and prevalent IAV subtypes varied per year and per site over the winters of November 2014 to January 2018. All H5 and H7 IAVs isolated during the surveillance period were LPAIVs and were highly similar to isolates obtained from different locations along the EAAF.…”

“…Supporting recent reports that IAVs from wild birds do not always follow rigid flyway boundaries and that there is intercontinental movement of IAV gene pools carried by wild fowl, some of the HA and NA genes of our isolates also cluster with a number of North American isolates. In addition, as shown by the present study and previous results on the surveillance of avian influenza viruses in South Korea 14 , percent IAV-positivity of samples tends to fluctuate across the years; however, we currently have no specific explanation for this interannual variability.…”

“…The sampling sites are known stopover points of migratory birds, especially those coming from Far East Siberia during the annual winter migration along the East Asian-Australasian Flyway (EAAF). As in our previous study that covered winters of 2009 to 2013 14 , the stopover sites were selected for their proximity to previous sites of HPAI outbreaks. A total of 6758 fecal samples were collected throughout the study (Fig.…”

Membrane Rigidity‐Tunable Fusogenic Nanosensor for High Throughput Detection of Fusion‐Competent Influenza A Virus

“…We further examined the colloidal stability of sLipo–Chol to study their compatibility with biological samples, here bird feces, generally collected from migratory stopover sites or infected birds for continuous surveillance of IAV (Figure S10, Supporting Information). [ 41 ] The avian feces dispersed in phosphate‐buffered saline were briefly centrifugated, and the supernatant solution was incubated with sLipo–Chol for 20 min, followed by incubation with sodium acetate buffer (0.3 m , pH 5.2) for 1 h. Interestingly, sLipo(u)–Chol 50 displayed a sudden increase in FRET ratio change, while three sLipo–Chol formulations showed resistance to fecal samples to some extent. Diverse compositions of fecal fluids likely contribute to the destabilization of unsaturated lipid membranes, as highlighted by the fact that avian feces contain nitrogenous waste (such as uric acid), gastrointestinal excrement (such as bile salts), and other insoluble components.…”