Avian influenza surveillance reveals presence of low pathogenic avian influenza viruses in poultry during 2009-2011 in the West Bengal State, India

Abstract

IntroductionMore than 70 outbreaks of the highly pathogenic avian influenza (HPAI) H5N1 have been reported in poultry in the western and north-eastern parts of India. Therefore, in view of the recent HPAI H5N1 outbreaks in poultry, active AI surveillance encompassing wild, resident, migratory birds and poultry was undertaken during 2009–2011 in the State of West Bengal.MethodsA total of 5722 samples were collected from West Bengal; 3522 samples (2906 fecal droppings + 616 other environmental samples) were from migratory birds and 2200 samples [1604 tracheal, cloacal swabs, environmental samples, tissue samples + 596 blood (serum)] were from domestic ducks and poultry. All tracheal, cloacal and environmental samples were processed for virus isolation. Virus isolates were detected using hemagglutination assay and identified using hemagglutination inhibition (HI) and reverse transcriptase polymerase chain reaction (RT-PCR) assays. Sequencing and phylogenetic analysis of partial region of the hemagglutinin and neuraminidase genes was done. Intravenous pathogenicity index assays were performed in chickens to assess pathogenicity of AI virus isolates. Serum samples were tested for detection of antibodies against AI viruses using HI assay.ResultsA total of 57 AI H9N2, 15 AI H4N6 and 15 Newcastle Disease (NDV) viruses were isolated from chickens, from both backyard and wet poultry markets; AI H4N6 viruses were isolated from backyard chickens and domestic ducks. Characterization of AI H9N2 and H4N6 viruses revealed that they were of low pathogenicity. Domestic ducks were positive for antibodies against H5 and H7 viruses while chickens were positive for presence of antibodies against AI H9N2 and NDV.ConclusionsIn the current scenario of HPAI H5N1 outbreaks in West Bengal, this report shows presence of low pathogenic AI H9N2 and H4N6 viruses in chickens and domestic ducks during the period 2009–2011. This is the first report of isolation of H4N6 from India. Antibodies against AI H5 and H7 in ducks highlight the probable role of domestic ducks in the transmission of AI viruses. Human infections of H9N2 have been reported from China and Hong Kong. This necessitates implementation of prevention and control measures to limit the spread of AI viruses.

Wild bird surveillance around outbreaks of highly pathogenic avian influenza A(H5N8) virus in the Netherlands, 2014, within the context of global flyways

“…[28]. During large-scale surveillance activities in north India from 2009 to 2011, no avian influenza viruses had been detected in 3,522 wild bird samples [29]. To which extent migrating bird populations of different flyways come in direct or indirect contact (e.g.…”

Isolation and phylogenetic characterization of haemagglutinin and neuraminidase genes of H9N2 low pathogenicity avian influenza virus isolated from commercial layers in India

“…The analysis performed on the NA gene did not provided more precise information on the geographic origin of the viruses isolated in the present study. Although reports are available on incidences of LPAI in Northern/Eastern part of Indian subcontinent [16,20,27,28], there is no information available for the incidence of LPAI in Southern States of India. The present study focused on the circulation of H9N2 LPAI viruses in layer population of Southern regions where larger population of poultry are reared but the status of LPAI viruses has not been known particularly regarding to phylogenetic and evolutionary analysis of virus isolates/strains affecting poultry in this region.…”

“…Phylogenetically, the HA and NA genes of the H9N2 viruses from India clustered with those isolated from Bangladesh, Pakistan and the Middle East, although we were not able to conclude on their exact geographic origin. East and Central Asian flyways of migratory birds, comprise India in regular migratory route and extend beyond widely in West China, Mongolia and Central Siberia permitting possible interchange of AIVs between these areas and particularly with India [27]. It may reflect a geographical parameter for restriction of the viruses in the areas.…”

“…It may reflect a geographical parameter for restriction of the viruses in the areas. While the HPAI situations have efficiently been brought under control, LPAI virus got increasingly circulating and regularly reported in India [16,20,[27][28][29][30]. It is believed that during the early 2000s, H9N2 subtype viruses circulating in Pakistan and Middle East might have been introduced into India through regional poultry or migratory birds and subsequently in the intervening years of frequent antigenic drifts likely to have occurred in Indian LPAI-H9N2 viruses resulted in new drift variants which established themselves in domestic poultry population [31,32].…”

<b>Vírus da influenza aviária:</b> monitoramento em aves de subsistência criadas no entorno de sítios de aves migratórias no Brasil

“…Desta forma, boa parte das pesquisas realizadas até hoje em aves de subsistência centraram-se na detecção de anticorpos para os subtipos H5 e H7 (JOANNIS et al, 2008;COUACY-HYMANN et al, 2012b;MADSEN et al, 2013b) do AIV (por serem passíveis de notificação à OIE) e, esporadicamente, também para o subtipo H9 (PAWAR et al, 2012;SERRÃO et al, 2012). (BEVINS et al, 2014).…”