Comparative pathogenicity and environmental transmission of recent highly pathogenic avian influenza H5 viruses

Abstract

Strategies to control spread of highly pathogenic avian influenza (HPAI) viruses by wild birds appear limited, hence timely characterization of novel viruses is important to mitigate the risk for the poultry sector and human health. In this study we characterize three recent H5-clade 2.3.4.4 viruses, the H5N8-2014 group A virus and the H5N8-2016 and H5N6-2017 group B viruses. The pathogenicity of the three viruses for chickens, Pekin ducks and Eurasian wigeons was compared. The three viruses were highly pathogenic for chickens, but the two H5N8 viruses caused no to mild clinical symptoms in both duck species. The highest pathogenicity for duck species was observed for the most recent H5N6-2017 virus. For both duck species, virus shedding from the cloaca was higher after infection with group B viruses compared to the H5N8-2014 group A virus. Higher cloacal virus shedding of wild ducks may increase transmission between wild birds and poultry. Environmental transmission of H5N8-2016 virus to chickens was studied, which showed that chickens are efficiently infected by (fecal) contaminated water. These results suggest that pathogenicity of HPAI H5 viruses and virus shedding for ducks is evolving, which may have implications for the risk of introduction of these viruses into the poultry sector.

Susceptibility of Common Family Anatidae Bird Species to Clade 2.3.4.4e H5N6 High Pathogenicity Avian Influenza Virus: An Experimental Infection Study

“…Virus shedding from the infected Anatidae was mainly observed via the oral route as in previous experimental infection studies of Anatidae (Eurasian wigeons and mallards) and clade 2.3.4.4b and 2.3.4.4c H5 HPAIVs [14,20]. Further, two Eurasian wigeons shed virus into the cloaca in late phase of infection.…”

“…Several groups have examined pathogenicity of clade 2.3.4.4c (Group A) H5N2 or H5N8 HPAIVs, which circulated worldwide in 2014-2015, in Anatidae such as the American black duck (Anas rubripes), Baikal teal (Anas formosa), common teal (Anas crecca), Eurasian wigeon, lesser scaup (Aythya a nis), mallard, Mandarin duck (Aix galericulata), pintail, ruddy duck (Oxyura jamaicensis), and surf scoter (Melanitta perspicillata) [14][15][16][17][18][19][20][21][22][23]. Most studies showed that clade 2.3.4.4c HPAIVs caused subclinical infection in Anatidae, and that the viruses were mainly shed via the oral route.…”

Pathogenicity of H5N8 High Pathogenicity Avian Influenza Virus in Chickens and Ducks from South Korea in 2020–2021

“…Additionally, genetic analysis demonstrated that H5N8 viruses in the 2014–2016 outbreak was likely to transmit from wild birds to domestic ducks, and this played a central role in virus spread to domestic poultry [ 13 , 27 ]. A recent study about comparative pathogenicity of HPAI H5 viruses in Netherland also suggested that virus shedding of duck species including both domestic and wild ducks might increase transmission to the poultry sector [ 28 ]. Collectively, our results in ducks, as well as previous findings concerning Korean HPAI outbreaks, indicate that domestic ducks play an important role in transmission of H5N8 HPAI viruses in the field.…”

Metal-Based Nanomaterials: Work as Drugs and Carriers against Viral Infections

“…Virus infection has always been a threat to human and animal health. Typical viruses include hepatitis B virus [ 1 ], influenza virus [ 2 ], human immunodeficiency virus (HIV) [ 3 ], and coronavirus [ 4 ], etc., which can cause severe disease. Therefore, antiviral drug development is a major research direction for scientists.…”