Live Bird Markets in Nigeria: A Potential Reservoir for H9N2 Avian Influenza Viruses

Abstract

Since 2006, multiple outbreaks of avian influenza (AI) have been reported in Nigeria involving different subtypes. Surveillance and molecular epidemiology have revealed the vital role of live bird markets (LBMs) in the dissemination of AI virus to commercial poultry farms. To better understand the ecology and epidemiology of AI in Nigeria, we performed whole-genome sequencing of nineteen H9N2 viruses recovered, from apparently healthy poultry species, during active surveillance conducted in nine LBMs across Nigeria in 2019. Analyses of the HA gene segment of these viruses showed that the H9N2 strains belong to the G1 lineage, which has zoonotic potential, and are clustered with contemporary H9N2 identified in Africa between 2016 and 2020. We observed two distinct clusters of H9N2 viruses in Nigeria, suggesting different introductions into the country. In view of the zoonotic potential of H9N2 and the co-circulation of multiple subtypes of AI virus in Nigeria, continuous monitoring of the LBMs across the country and molecular characterization of AIVs identified is advocated to mitigate economic losses and public health threats.

Live pig markets are hotspots for spread of African swine fever virus in Nigeria

“…The live animal market trade system plays a crucial role in the introduction of pathogens into new areas particularly long-distance disease spread (Martin et al, 2011;Zhou et al, 2015). Likewise, previous studies have described the important role of the live bird market in the epidemiology of avian influenza in Nigeria, but no report on the role of LPMs in the epidemiology of ASF in the country (Coker et al, 2014;Sulaiman et al, 2021). This study has demonstrated that ASFV is circulating in LPMs in Nigeria.…”

“…However, these studies involved only one pig market with limited information on activities and pig movements in and out of the market. Studies in Nigeria have revealed that live bird markets play an important role in the ecology and epidemiology of Avian influenza in Nigeria (Coker et al, 2014;Fusaro et al, 2009;Sulaiman et al, 2021). Similarly, it has been reported that livestock farmers in Nigeria sell their animals through live animal markets to mitigate economic losses during disease outbreaks (Bolajoko et al, 2019).…”

Detection of Newcastle Disease antibodies amongst local chicken slaughtered in live bird markets in Kaduna, Nigeria

“…This is therefore, a great threat to rural and commercial poultry production in Kaduna State. The implication of the spread and the carrier status of the rural household chickens could be of importance considering the fact that free ranged chickens were reported to constitute almost 50% of chicken population in Nigeria and are capable of scavenging around the environment spreading the NDV and other avian viral diseases to vaccinated and unvaccinated healthy exotic birds (FAO, 2018;Bitrus et al, 2020;Sulaiman et al, 2021). This study recorded an overall seroprevalence of 23% in the study area.…”

Avian influenza H5N1: still a pandemic threat?

“…High levels of avian influenza viruses of public health concern (e.g. H5N1, H7N9, H9N2) have been detected in LBMs throughout Asia, the Middle East and Africa through longitudinal surveillance initiatives [8][9][10][11][12] . Indeed, many human cases of AIV infection have been associated with contact with poultry at LBMs 13,14 .…”

“…Despite the current low number of human cases, influenza H5N1 circulation in poultry has continued unabated. Viral surveillance in LBMs has established that H5N1 circulation is occurring at levels similar to those detected during the peak period of human infections [8][9][10][11][12] . The current lack of human H5N1 cases may be linked to the dominant strain currently circulating (clade 2.3.2.1) being more 'avian-like' and not as readily able to jump the species gap to infect humans 25 .…”