Semi-Scavenging Poultry as Carriers of Avian Influenza Genes.

A T M Badruzzaman,Md Jamal Uddin,Mahmudul Hasan,Asmaul Husna,Ferdaus Mohd Altaf Hossain,Mohammed Giasuddin,Mohammad Rafiqul Islam,Mohammed Kawser Hossain,Hossam M Ashour,Jahangir Alam,Md Masudur Rahman,Folorunso Oludayo Fasina,Seong-Kug Eo

doi:10.3390/life12020320

Abstract

Ducks are the natural reservoir of influenza A virus and the central host for the avian influenza virus (AIV) subtype H5N1, which is highly pathogenic. Semi-scavenging domestic ducks allow for the reemergence of new influenza subtypes which could be transmitted to humans. We collected 844 cloacal swabs from semi-scavenging ducks inhabiting seven migratory bird sanctuaries of Bangladesh for the molecular detection of avian influenza genes. We detected the matrix gene (M gene) using real-time RT–PCR (RT–qPCR). Subtyping of the AIV-positive samples was performed by RT–qPCR specific for H5, H7, and H9 genes. Out of 844 samples, 21 (2.488%) were positive for AIV. Subtyping of AIV positive samples (n = 21) revealed that nine samples (42.85%) were positive for the H9 subtype, five (23.80%) were positive for H5, and seven (33.33%) were negative for the three genes (H5, H7, and H9). We detected the same genes after propagating the virus in embryonated chicken eggs from positive samples. Semi-scavenging ducks could act as carriers of pathogenic AIV, including the less pathogenic H9 subtype. This can enhance the pathogenicity of the virus in ducks by reassortment. The large dataset presented in our study from seven areas should trigger further studies on AIV prevalence and ecology.

Highlights

Influenza viruses pose a persistent public health threat for the global population
Identification of Avian Influenza Virus (AIV) Type A To determine the prevalence of avian influenza virus (AIV) type A, RT–qPCR assays were performed
844 samples, 21 were positive for AIV Type A, and the positive results were confirmed by both hemagglutination activity (HA) and Hemagglutination inhibition (HI) assays (Table 3)

Summary

Introduction

Influenza viruses pose a persistent public health threat for the global population. These viruses cause mild to severe illness with various respiratory and gastrointestinal symptoms. As of April 2021, the records of the WHO indicated 862 human H5N1 cases from 17 different countries, including Bangladesh [7,8] Other influenza subtypes such as H5N2, H5N3, H5N5, H5N6, H5N8, H5N9, H7N1, H7N2, H7N3, H7N7, H7N8, H7N9, and H9N2 have been isolated from different parts of the world [9,10]. AIVs replicate in the respiratory and intestinal epithelial cells of their natural reservoirs (wild waterfowl, gulls, dabbling ducks, geese, seabirds, and shorebirds) [13,14,15,16]. They are excreted through feces into the environment [17,18]. Migratory wild birds may have contributed to the spread of AIVs along the Central Asian Flyway and on a global level [19,20]

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Conclusion