Evidence of exposure of domestic pigs to Highly Pathogenic Avian Influenza H5N1 in Nigeria

Clement Meseko,Elke Starick,Donata Hoffman,Chika Nwosuh,Anja Globig,Timm Harder,Tony Joannis,David Shamaki,Anne Pohlmann,Martin Beer,Thomas Mettenleiter,Jeremiah Ijomanta

doi:10.1038/s41598-018-24371-6

Clement Meseko, Elke Starick + Show 10 more

Open Access

https://doi.org/10.1038/s41598-018-24371-6

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Abstract

Avian influenza viruses (AIV) potentially transmit to swine as shown by experiments, where further reassortment may contribute to the generation of pandemic strains. Associated risks of AIV inter-species transmission are greater in countries like Nigeria with recurrent epidemics of highly pathogenic AI (HPAI) in poultry and significant pig population. Analysis of 129 tracheal swab specimens collected from apparently healthy pigs at slaughterhouse during presence of HPAI virus H5N1 in poultry in Nigeria for influenza A by RT-qPCR yielded 43 positive samples. Twenty-two could be determined by clade specific RT-qPCR as belonging to the H5N1 clade 2.3.2.1c and confirmed by partial hemagglutinin (HA) sequence analysis. In addition, 500 swine sera were screened for antibodies against influenza A virus nucleoprotein and H5 HA using competition ELISAs and hemagglutination inhibition (HI) tests. Serologically, 222 (44.4%) and 42 (8.4%) sera were positive for influenza A virus NP and H5 antibodies, respectively. Sera reacted to H5N1 and A/H1N1pdm09 strains by HI suggesting exposure of the Nigerian domestic pig population to these viruses. We report for the first time in Nigeria, exposure of domestic pigs to H5N1 virus. This poses potential public health and pandemic risk due to interspecies transmission of avian and human influenza viruses.

Highlights

Scientific investigations predict that avian influenza viruses (AIV) might adapt in swine host and contribute to the generation of a potentially pandemic strain through genetic reassortment between avian and human viruses[1]
Healthy domestic pigs from backyard and free range husbandry system in Plateau State, north central Nigeria slaughtered at the Jos central abattoir from 2015–2016 were investigated
Forty three of 129 (33%) tracheal swab specimens collected from these pigs were positive for influenza A virus (M and NP) genes by conventional and RT-qPCR assays

Summary

Introduction

Scientific investigations predict that avian influenza viruses (AIV) might adapt in swine host and contribute to the generation of a potentially pandemic strain through genetic reassortment between avian and human viruses[1]. The risks involved in this inter-species transmission of influenza virus and the odd that reassortment of genes in pigs as a mixing vessel would occur is greater in countries like Nigeria with recurrent epidemics of HPAI in regions with high pigs population often in direct contact with poultry. This is because lapses in biosecurity provide ample opportunities for intra- and inter-species co-infections[7].

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