Evidence of the Presence of Low Pathogenic Avian Influenza A Viruses in Wild Waterfowl in 2018 in South Africa.

Marjolein J Poen,Robert G Webster,Mohamed E El Zowalaty,Richard J Webby,Ron A M Fouchier

doi:10.3390/pathogens8040163

Abstract

Avian influenza viruses are pathogens of global concern to both animal and human health. Wild birds are the natural reservoir of avian influenza viruses and facilitate virus transport over large distances. Surprisingly, limited research has been performed to determine avian influenza host species and virus dynamics in wild birds on the African continent, including South Africa. This study described the first wild bird surveillance efforts for influenza A viruses in KwaZulu-Natal Province in South Africa after the 2017/2018 outbreak with highly pathogenic avian influenza virus H5N8 in poultry. A total of 550 swab samples from 278 migratory waterfowl were tested using real-time RT-PCR methods. Two samples (0.7%) were positive for avian influenza virus based on the matrix gene real-time RT-PCR but were negative for the hemagglutinin subtypes H5 and H7. Unfortunately, no sequence information or viable virus could be retrieved from the samples. This study shows that avian influenza viruses are present in the South African wild bird population, emphasizing the need for more extensive surveillance studies to determine the South African avian influenza gene pool and relevant local host species.

Highlights

Avian influenza viruses (AIVs) continue to pose a threat to both animal and human health worldwide
Wild bird surveillance efforts in South Africa are very limited [17,18,19,20], despite the fact that South Africa may be at a constant risk of highly pathogenic avian influenza (HPAI) introduction because of its wild bird flyway connection to and overlap with areas where HPAI viruses have/may become endemic, like Egypt [21], and infections in South African poultry have been described [19,22,23,24]
To the authors’ knowledge, the most recently published reports describing the detection of AIVs in living wild birds in South Africa (H1N8 and H4N2 in Egyptian geese) date back to 2007–2009 [19,20], apart from published detections of HPAI H5 viruses in outbreak-related wild bird screening [25]

Summary

Introduction

Avian influenza viruses (AIVs) continue to pose a threat to both animal and human health worldwide. AIVs of the H5 and H7 subtypes are further classified into low pathogenic avian influenza (LPAI) and highly pathogenic avian influenza (HPAI) viruses based on molecular markers and mortality rates in experimentally intravenously inoculated chickens [6]. In contrast to LPAI viruses, HPAI viruses cause high morbidity and mortality in poultry, but cause a spectrum of disease in wild. HPAI viruses have been reported to infect humans, resulting in high case mortality rates [7]. In 2005, HPAI viruses of the H5N1 subtype were detected in Asia, Europe, the Middle East and Africa, including South Africa, causing devastating economical losses due to numerous infections in both poultry and wild birds [7,8]. Three other HPAI H5 subtypes emerged: H5N8 in

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