Avian influenza revisited: concerns and constraints

Viruses and Viral Infections in Developing Countries, 2020

gle-stranded negative-sense RNA [1]. There are four main influenza virus species, namely A, B, C and D. Type A viruses are known to infect a wide range of birds and mammals while the other species have more constrained host ranges. Influenza A viruses (IAV), including all avian influenza viruses, possess eight separate genomic segments

Journal of Food, …, 2009

The emergence of highly pathogenic avian influenza (HPAI) of Asian lineage and the subsequent spillover to other part of the globe and on going spread of Eurasian-Africa H5N1 epidemic into domestic, wild birds and human have generated unprecedented attention in recent times and threat of potential pandemic via the avian-human link. Historically, from 1878 through 1955, fowl plaque was described as a high mortality disease of poultry in many countries throughout Europe, Asia, North and South America and Africa and the etiology was proved to be a filterable virus. In the 1930s through the 1950s, fowl plaque disappeared as an endemic disease in most part of the world. In 1949, the first report of a low virulent disease in chickens caused by LPAI virus was reported. In 1955, the etiological of fowl plaque was determined to be influenza A virus, which subsequently was identified as the H7 subtype. In 1959, a "fowl plaque-like" outbreak was described in chickens, which was the first report of fowl plaque caused by a non-H7 AI virus, i.e. first fowl plaque outbreak from H5 subtype of AI virus. In 1961 the first wild birds infection and deaths were reported in common terns of South Africa. In 1966 and 1971, the first H5 and H7 LPAI viruses, respectively were identified; prior to this period, only HPAI viruses had H5 and H7 subtypes. In 1970, the AGID serological test was introduced, which allowed easy and rapid identification of AI virus-infected poultry flocks. In 1972, there was the first isolation of LPAI viruses in asymptomatic wild birds: ducks in the United State and shorebirds in Australia. In 1981, the term "highly pathogenic avian influenza" was accepted as standard nomenclature for fowl plaque and related synonyms. In 1983, LPAI virus was observed mutating to HPAI virus during LPAI field outbreak, and specific genomic changes were identified in the proteolytic cleavage site of the hemagglutinin responsible for the virulence change. In the late 1980s and early 1990s, molecular criteria were added to the definition for classifying an AI virus as HPAI. In 2002, there were the first reported infections and deaths in a wide variety of wild bird species from AI virus H5N1 HPAI virus. The primary goal of this review is to highlight the global situation of HPAI and provide baseline information to show the potential pandemic nature of the virus, so that control and prevention strategies can be improved.

Medical Science Monitor, 2023

Strains of avian influenza A, believed to have originated in poultry with transmission to wild birds, have been associated with epidemics and four major pandemics in humans in the past century. The 1918 influenza pandemic was caused by an avian strain of the influenza A(H1N1) virus that initially adapted to infect humans and then rapidly spread between humans. Since 2021, highly pathogenic avian influenza (HPAI) virus subtypes have been identified in poultry and wild birds. In October 2022, the HPAI virus variant A(H5N1) was isolated from intensively farmed American mink. The World Health Organization (WHO), the US Centers for Disease Control and Prevention (CDC), and the European Union Reference Laboratory for Avian Influenza (EURL) have stated that the risk of human infection from birds and mammals and human-to-human transmission from known HPAI viruses is currently low. However, they recommend increased infection surveillance and preparedness. This editorial aims to present the status of HPAI virus transmission in poultry, wild birds, and mammals to highlight the importance of international infection surveillance, control, and preparedness to prevent the next human influenza pandemic.

British journal of nursing, 2005

Advances in Animal and Veterinary Sciences, 2014

The Asian lineage of H5N1 avian influenza virus emerged from geese (A/Goose/Guangdong/1/96) in China in 1996, and is continuing its spread infecting domestic poultry, other birds and sporadic infection to humans revealing its pandemic potential. Since late 2003, H5N1 virus has been reported over 60 counties in Asia, Europe and Africa killing millions of poultry and infected humans in 16 countries with a total of 650 confirmed cases including 386 fatal have been reported to WHO. Spread of H5N1 virus has been linked with bird migration, although trade of poultry and poultry products has also been attributed in the spread. During the last one and half decades of circulation in poultry, the H5N1 virus has undergone significant genetic diversification leading to emergence of 10 major virus clades (clades 0-9), with subsequent diversification into 2nd-, 3rd-and 4th-order clades. Vaccination is one of the strategies for control and prevention of H5N1 virus infection; however, some countries still face challenges to eliminate H5N1 virus in poultry. One of the major problems is antigenic drift in viruses that develops due to vaccine pressure, particularly when vaccination is not implemented properly. Two classes of anti-viral drugs (neuraminidase inhibitors and adamantanes) are available for treatment and prophylaxis of influenza; however, there is emergence of drug resistant variants in poultry and humans. Widespread circulation and ever changing nature of H5N1 virus make avian influenza control program more difficult. Therefore, educational programs to enhance awareness on avian influenza, animal husbandry practices and biosecurity measures are important in control of the disease. All copyrights reserved to Nexus® academic publishers

Future microbiology, 2013

Clinical Infectious Diseases, 2007

Avian Diseases, 2016