Surveillance of Influenza A Virus and Its Subtypes in Migratory Wild Birds of Nepal.

Dibesh Karmacharya,Nitish Debnath,Pratikshya Adhikari,Tarka Bhatta,Jean-Marc Hero,Mohinder Oberoi,Adarsh Man Sherchan,Khadak Bisht,Maheshwar Dhakal,Bishwo Shrestha,Manisha Bista,Rajesh Rajbhandari,Ajay Sharma,Ravi Dissanayake,Sulochana Manandhar,Jane Hughes,Guihong Zhang

doi:10.1371/journal.pone.0133035

Dibesh Karmacharya, Nitish Debnath + Show 15 more

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https://doi.org/10.1371/journal.pone.0133035

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Abstract

Nepal boarders India and China and all three countries lie within the Central Asian Flyway for migratory birds. Novel influenza A H7N9 caused human fatalities in China in 2013. Subclinical infections of influenza A H7N9 in birds and the potential for virus dispersal by migratory birds prompted this study to assess avian H7N9 viral intrusion into Nepal. Surveillance of influenza A virus in migratory birds was implemented in early 2014 with assistance from the Food and Agricultural Organization (FAO). Of 1811 environmental fecal samples collected from seven wetland migratory bird roosting areas, influenza A H9N2 was found in one sample from a ruddy shelduck in Koshi Tappu Wildlife Reserve located in southern Nepal. Avian H7N9 and other highly pathogenic avian influenza viruses were not detected. This study provides baseline data on the status of avian influenza virus in migratory bird populations in Nepal.

Highlights

Wild birds, aquatic species, are considered natural hosts of avian influenza virus (AIV) [1, 2]
Once introduced into domestic birds, low Low pathogenic avian influenza viruses (LPAIV) occasionally undergo spontaneous mutations transforming into highly pathogenic avian influenza virus (HPAIV) variants [4, 5]
The HPAIV H5N1 that emerged in late 2003 in Southeast Asia spread throughout East Asia, PLOS ONE | DOI:10.1371/journal.pone

Summary

Introduction

Aquatic species, are considered natural hosts of avian influenza virus (AIV) [1, 2]. Low pathogenic avian influenza viruses (LPAIV) have co-evolved with their wild host populations to such an extent that infections usually remain subclinical [2]. Wild birds may transmit LPAIV directly or indirectly to poultry, such infections are generally not sustained [3]. Once introduced into domestic birds, low LPAIV occasionally undergo spontaneous mutations transforming into highly pathogenic avian influenza virus (HPAIV) variants [4, 5]. AIV often attains high virulence, transmissibility, and tissue tropism and cover affects a wide host range due to its potential to evolve with capricious genetic shuffling [3]. The HPAIV H5N1 that emerged in late 2003 in Southeast Asia spread throughout East Asia, PLOS ONE | DOI:10.1371/journal.pone.0133035 July 15, 2015

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