Avian influenza virus, a very sticky situation (original) (raw)
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The emerging influenza virus threat: status and new prospects for its therapy and control
Archives of virology, 2018
Influenza A viruses (IAVs) are zoonotic pathogens that cause yearly outbreaks with high rates of morbidity and fatality. The virus continuously acquires point mutations while circulating in several hosts, ranging from aquatic birds to mammals, including humans. The wide range of hosts provides influenza A viruses greater chances of genetic re-assortment, leading to the emergence of zoonotic strains and occasional pandemics that have a severe impact on human life. Four major influenza pandemics have been reported to date, and health authorities worldwide have shown tremendous progress in efforts to control epidemics and pandemics. Here, we primarily discuss the pathogenesis of influenza virus type A, its epidemiology, pandemic potential, current status of antiviral drugs and vaccines, and ways to effectively manage the disease during a crisis.
The Journal of Infectious Diseases, 2023
The antiviral susceptibility of currently circulating (2022–2023) highly pathogenic avian influenza (HPAI) A(H5N1) viruses was assessed by genotypic and phenotypic approaches. The frequency was low for neuraminidase (NA) and polymerase acidic (PA) substitutions associated with reduced inhibition by NA inhibitors (21/2698, 0.78%) or the PA inhibitor baloxavir (14/2600, 0.54%). Phenotypic testing of 22 clade 2.3.2.1a and 2.3.4.4b viruses revealed broad susceptibility to NA inhibitors and baloxavir for a conclusion that most contemporary HPAI A(H5N1) viruses retain susceptibility to antiviral drugs. Novel NA-K432E and NA-T438I substitutions (N2 numbering) were identified at elevated frequencies (104/2698, 3.85%) and caused reduced zanamivir and peramivir inhibition.
Highly pathogenic H5N1 avian influenza virus: Cause of the next pandemic?
Comparative Immunology, Microbiology and Infectious Diseases, 2009
Since 1997, when human infections with a highly pathogenic (HP) avian influenza A virus (AIV) subtype H5N1 -previously infecting only birds -were identified in a Hong Kong outbreak, global attention has focused on the potential for this virus to cause the next pandemic. From December 2003, an unprecedented H5N1 epizootic in poultry and migrating wild birds has spread across Asia and into Europe, the Middle East, and Africa. Humans in close contact with sick poultry and on rare occasion with other infected humans, have become infected. As of early March 2007, 12 countries have reported 167 deaths among 277 laboratory-confirmed human infections to WHO. WHO has declared the world to be in Phase 3 of a Pandemic Alert Period. This paper reviews the evolution of HP AIV H5N1, molecular changes that enable AIVs to infect and replicate in human cells and spread efficiently from person-to-person, and strategies to prevent the emergence of a pandemic virus. #
Evolution and Spread of Avian Influenza H5N1 Viruses
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