The Pattern of Highly Pathogenic Avian Influenza H5N1 Outbreaks in South Asia

Abstract

Highly pathogenic avian influenza (HPAI) H5N1 has caused severe illnesses in poultry and in humans. More than 15,000 outbreaks in domestic birds from 2005 to 2018 and 861 human cases from 2003 to 2019 were reported across the world to OIE (Office International des Epizooties) and WHO (World Health Organization), respectively. We reviewed and summarized the spatial and temporal distribution of HPAI outbreaks in South Asia. During January 2006 to June 2019, a total of 1063 H5N1 outbreaks in birds and 12 human cases for H5N1 infection were reported to OIE and WHO, respectively. H5N1 outbreaks were detected more in the winter season than the summer season (RR 5.11, 95% CI: 4.28-6.1). Commercial poultry were three times more likely to be infected with H5N1 than backyard poultry (RR 3.47, 95% CI: 2.99-4.01). The highest number of H5N1 outbreaks was reported in 2008, and the smallest numbers were reported in 2014 and 2015. Multiple subtypes of avian influenza viruses and multiple clades of H5N1 virus were detected. Early detection and reporting of HPAI viruses are needed to control and eliminate HPAI in South Asia.

Identification of Important N-Linked Glycosylation Sites in the Hemagglutinin Protein and Their Functional Impact on DC-SIGN Mediated Avian Influenza H5N1 Infection

“…The first reported human infected with the highly pathogenic avian influenza (HPAI) H5N1 virus was recorded in Hong Kong, 1997 [ 1 ]. Subsequently, the spread of HPAI H5N1 viruses in poultry and sporadic human infections are perceived as a potential pandemic threat [ 2 , 3 ]. At present, there are several clades and subclades being identified based on their genetic and antigenic variation of the viral haemagglutinin (HA5) and neuraminidase (NA1) genes.…”

Human infection with Avian influenza A virus in Nepal: requisite for timely management and preparedness

“…Since then, several periodic outbreaks of Avian Influenza subtypes H 5 and H 9 have been reported in poultry [13,17]. The highly pathogenic avian influenza (HPAI) in birds was caused by the influenza virus of the strains H 5 N 1 of the clade 2.2 and later by 2.3.2.1a and H 5 N 8 of the clade 2.3.4.4 [10,24], which are the same viral clades reported from South Asian countries including China and India [10,17]. Moreover, frequent outbreaks of HPAI of different strains in China [9,18] and India [9,10] further increases the threat of HPAI in Nepal.…”

“…The highly pathogenic avian influenza (HPAI) in birds was caused by the influenza virus of the strains H 5 N 1 of the clade 2.2 and later by 2.3.2.1a and H 5 N 8 of the clade 2.3.4.4 [10,24], which are the same viral clades reported from South Asian countries including China and India [10,17]. Moreover, frequent outbreaks of HPAI of different strains in China [9,18] and India [9,10] further increases the threat of HPAI in Nepal. This is not just due to the long porous border, and cross border movement of birds between its neighbors but also unmanaged local markets, informal trade and uncontrolled movement of birds (wild and domestic) [24].…”

“…Avian influenza viruses do not usually infect humans. However, sporadic human infections with these viruses have been reported mainly in the Western Pacific Region like Vietnam, China, and Cambodia [10]. Globally, since 2003 a total of 861 cases of human infection with avian influenza A (H5N1) virus, predominantly of the clade 2.3.4.4, was reported from 17 countries [29] ( Fig.…”

“…However, in Nepal, the first human case of H5N1 was reported in April 2019, resulting in the death of a patient, which is the world's first H5N1 human infection since 2017 [6]. Other neighboring countries of Nepal, such as Pakistan [10] and Bangladesh [10] in South Asia, have also experienced episodes of AIV in humans ( Table 1).…”