A Global Perspective on H9N2 Avian Influenza Virus

Abstract

H9N2 avian influenza viruses have become globally widespread in poultry over the last two decades and represent a genuine threat both to the global poultry industry but also humans through their high rates of zoonotic infection and pandemic potential. H9N2 viruses are generally hyperendemic in affected countries and have been found in poultry in many new regions in recent years. In this review, we examine the current global spread of H9N2 avian influenza viruses as well as their host range, tropism, transmission routes and the risk posed by these viruses to human health.

Wild Birds in Live Birds Markets: Potential Reservoirs of Enzootic Avian Influenza Viruses and Antimicrobial Resistant Enterobacteriaceae in Northern Egypt

“…Wild birds are responsible for the transcontinental spread of influenza viruses over thousands of kilometers and spill over to domestic birds and threaten human health. Few AIV subtypes become as well adapted to poultry as the panzootic goose/Guangdong lineage H5Nx viruses, the recent Chinese H7N9 viruses, and multiple Eurasian H9N2 lineages and present a major threat to veterinary and human health, while others quickly disappeared [24].…”

Phylogeographic Dynamics of Influenza A(H9N2) Virus Crossing Egypt

“…Low pathogenic avian influenza virus (LPAIV) of subtype H9N2 is a subtype of influenza A viruses that circulate among different bird species and possess a public health concern because of its zoonotic potential (Peacock et al, 2019). Based on their genetic features, H9N2 viruses are classified into two major lineages, i.e., the "North American" and "Eurasian" lineages, circulating in poultry and wild birds.…”

“…Phylogenetically, the Egyptian LPAIVs H9N2 have been described to be diversified further into three groups clustered within G1-B lineage based on their HA gene segment Naguib et al, 2017). It is generally acknowledged that waterfowl migration and poultry trade play an important role in the spread of AIVs (Peacock et al, 2019). However, the geographic diffusion of H9N2 globally and into and within Egypt is not fully understood.…”

Genetic determinants of receptor-binding preference and zoonotic potential of H9N2 avian influenza viruses

“…In the 1990s avian influenza virus subtypes H5N1 and H9N2 underwent a host-switch from wild birds to domestic poultry where they have circulated ever since. H9N2 has since become one of the most widespread strains in poultry, infecting domestic fowl throughout Asia and North Africa, where it circulates hyper-endemically [1–4]. Zoonotic H9N2 cases are also occasionally detected, with human infections reported in Hong Kong, mainland China, Bangladesh, Egypt, Pakistan, Oman, Indian and Senegal; over half of human infections have been reported in the last 4 years alone, all of which indicates a growing pandemic threat from these viruses [4–12].…”

“…H9N2 has since become one of the most widespread strains in poultry, infecting domestic fowl throughout Asia and North Africa, where it circulates hyper-endemically [1–4]. Zoonotic H9N2 cases are also occasionally detected, with human infections reported in Hong Kong, mainland China, Bangladesh, Egypt, Pakistan, Oman, Indian and Senegal; over half of human infections have been reported in the last 4 years alone, all of which indicates a growing pandemic threat from these viruses [4–12]. Although no human-to-human transmission has been recorded, some H9N2 virus strains have shown a high propensity for airborne transmission between ferrets [13, 14], the most commonly used model for human influenza transmission.…”