Live poultry market workers are susceptible to both avian and swine influenza viruses, Guangdong Province, China

Abstract

Guangdong Province is recognized for dense populations of humans, pigs, poultry and pets. In order to evaluate the threat of viral infection faced by those working with animals, a cross-sectional, sero-epidemiological study was conducted in Guangdong between December 2013 and January 2014. Individuals working with swine, at poultry farms, or live poultry markets (LPM), and veterinarians, and controls not exposed to animals were enrolled in this study and 11 (4 human, 3 swine, 3 avian, and 1 canine) influenza A viruses were used in hemagglutination inhibition (HI) assays (7 strains) and the cross-reactivity test (9 strains) in which 5 strains were used in both tests. Univariate analysis was performed to identify which variables were significantly associated with seropositivity. Odds ratios (OR) revealed that swine workers had a significantly higher risk of elevated antibodies against A/swine/Guangdong/L6/2009(H1N1), a classical swine virus, and A/swine/Guangdong/SS1/2012(H1N1), a Eurasian avian-like swine virus than non-exposed controls. Poultry farm workers were at a higher risk of infection with avian influenza H7N9 and H9N2. LPM workers were at a higher risk of infection with 3 subtypes of avian influenza, H5N1, H7N9, and H9N2. Interestingly, the OR also indicated that LPM workers were at risk of H1N1 swine influenza virus infection, perhaps due to the presence of pigs in the LPM. While partial confounding by cross-reactive antibodies against human viruses or vaccines cannot be ruled out, our data suggests that animal exposed people as are more likely to have antibodies against animal influenza viruses.

Avian influenza A (H9N2) virus infections among poultry workers, swine workers, and the general population in Beijing, China, 2013‐2016: A serological cohort study

“…Our cohort study did not reveal any differences in the risk of contracting H9N2 virus between the swine workers and the general population, which is consistent with a previous study's findings . Indeed, the poultry workers had a higher risk than the general population of contracting an H9N2 infection, similar to that reported previously . The higher risk of infection with H9N2 virus among poultry workers suggests that increased exposure to poultry would heighten the risk of contracting this virus.…”

“…11 Second, our study did not involve workers from live poultry markets, because these markets were banned in Beijing after 2005, but the participants in some of the other serological studies on H9N2 AIV included live poultry market workers. Furthermore, a cross-sectional, seroepidemiological study conducted in Guangdong Province showed that the seroprevalence of anti-H9N2 antibodies in the poultry market workers was much higher than in the poultry farm workers and veterinary staff, 40 of another study. 41 Third, people in the southern provinces prefer to eat fresh rather than frozen poultry, and this increases their exposure to the virus.…”

“…The incidence density rate for H9N2 viral infections (from 2013 to 2015, 3.08 per 1000 person‐months) among all the study participants was found to be higher than those for H7N9 (0.4 per 1000 person‐months) and H5N1 (1.3 per 1000 person‐months) infections observed in the same period with the same population (HI assay; HI cutoff titer, 80). Another study conducted in Guangdong Province, China, also revealed that the seroprevalence of anti‐H9N2 antibodies (6.79%) was higher than for H7N9 (3.95%), H5N1 (1.36%), and even avian‐like canine H3N2 (1.85%) (HI assay; HI cutoff titer, 40). A prospective, controlled, seroepidemiological Egyptian study also reported that the seroprevalence of H9N2 among exposed humans was 5.6%‐7.5% higher than for anti‐A (H5N1) antibodies (2%) (MN assay) .…”

Insight into live bird markets of Bangladesh: an overview of the dynamics of transmission of H5N1 and H9N2 avian influenza viruses

“…33 , 34 These differences between China and Bangladesh play an important role on the prevalence of different species within the live bird markets, as well as the prevalence of various subtypes of IAVs found and what impact this may have on public health. Despite these differences, the detection rate of AIVs in Bangladesh is relatively high (24%) compared to both Egypt (5%) 35 and China (4%), 36 which further emphasizes the need for both continued surveillance and implementation of standard precautions against IAV transmission and infection.…”

Characterizations of H4 avian influenza viruses isolated from ducks in live poultry markets and farm in Shanghai

“…in LPM enhances the reassortment potential of AIV. Close contact between humans and the LPM provides conditions for cross-species AIV transmission2829. For instance, most of the H7N9 infected humans had prior exposure to LPM, which was identified as the source of human H7N9 infection cases3031.…”