Avian Influenza Virus
System : Terrestrial
Kingdom
Phylum
Class
Order
Family
Virus
Orthomyxovirdae
- General
- Distribution
- Impact
- Management
- Bibliography
- Contact
Common name
fowl plague (English), bird flu (English), HPAI (English), LPAI (English)
Synonym
Similar species
Infectious laryngotracheitis (ILT), Acute Fowl Cholera, Chronic Respiratory Disease (CRD), Newcastle disease virus (NDV)
Summary
Asian Influenza is a highly contagious disease caused by type A influenza virus. Waterfowl are natural hosts of the disease and are usually asymptomatic. There are two forms of AI: Highly Pathogenic Avian Influenza (HPAI), which causes rapid mortality particularly in domestic poultry, and Low Pathogenic Avian Influenza (LPAI), which is a milder form. AI can be transmitted through the respiratory secretions or faeces of infected birds and also through contact with contaminated materials or items such as clothing, equipement and vehicles (Horimoto and Kawaoka, 2001).
Species Description
AI viruses have a similar structure and consist of two glycoprotein spikes, hemagglutinin (HA) and neuraminidase (NA) and a limited number of M2 proteins that project from the viral surface (NIAID, 2004). The virus is highly pleomorphic, roughly spherical, and filamentous (NIAID, 2004). Inside the virion are eight single-stranded RNA segments waiting to be copied by a host (NIAID, 2004).
Notes
LPAI can rapidly mutate into HPAI (Perdue et al. 1998) and its ability to cause fatal infections in humans (Horimoto and Kawaoka 2001; Guan et al. 2004) is of serious concern. If a human is simulataneously infected with human and AI viruses it is possible a new virus may emerge which could be transmitted from human to human. This has not occurred and the risks of this taking place are small, but the implications would be extremely serious (pandemic)
Lifecycle Stages
The virus replicates itself once inside a host cell. AI uses the genetic material of the host for energy and for the replication process. After viral components are made inside the host cell, the components are released (Sander, 2004).
Habitat Description
Waterbirds, especially Anatidae are natural reservoirs for AI which needs a host to reproduce (Horimoto and Kawaoka, 2001).
Reproduction
AI needs a host to reproduce. Once inside, the virus uses the hosts DNA to replicate itself (Horimoto and Kawaoka, 2001).
Nutrition
AI, like most viruses, has no metabolism. Therefore, the virus does not require any nutrition (Horimoto and Kawaoka, 2001).
Pathway
The virus is spread from one continent to another by migratory birds that are natural hosts for the disease. The virus has the potential to spread through agriculture industry, such as the poultry industry and live poultry markets. The virus has the potential to be spread through the food trade.
Principal source: Horimoto, T. and Kawaoka, Y. 2001. Pandemic Threat Posed by Avian Influenza A Viruses. Clinical Microbiology Reviews. 14: 129-149.
\n NIAID, 2004. Background: What we know about the flu.
APHIS, 2004. Highly pathogenic avian influenza.
\n CDC, 2004. Basic Information about avian influenza (bird flu).
Compiler: Elizabeth Lishka, supervised by Dr. Deborah Rudnick University of Washington, Tacoma.
Review: John Tracey, NSW Department of Primary Industries, Orange New South Wales, Australia
Publication date: 2005-12-30
Recommended citation: Global Invasive Species Database (2024) Species profile: Avian Influenza Virus. Downloaded from http://iucngisd.org/gisd/species.php?sc=529 on 12-12-2024.
General Impacts
The effects of AI are felt worldwide. The virus has had a significant impact on the economy, trade industry, chicken and animal health, and human health ( APHIS, 2004). For instance, in 1983 and 1984 the the United States government destroyed more than 17 million birds at a cost of 65 million dollars due to an outbreak of AI (APHIS, 2004). In 1997, 6 out of 18 people in Hong Kong infected with H5N1 (a subtype, see Avian Influenza Virus for more details on different types) died (CDC, 2004).
Management Info
Control measures include trade restrictions, and biocontrol security measures on farms and at live markets (APHIS , 2004), quarantine (Butcher, G. et al. 2004), surveillance and vaccines. Swift action following an outbreak of HPAI involves depopulation.
