Submitted to: Centre for Agriculture and Biosciences International
Publication Type: Book / chapter
Publication Acceptance Date: 9/21/2012
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Avian metapneumovirus (aMPV) is an economically important virus that is the primary causal agent of turkey rhinotracheitis (TRT), also known as avian rhinotracheitis (ART). The virus causes an acute highly contagious infection of the upper respiratory tract in turkeys and was first isolated from turkeys in South Africa during the late 1970s. Thereafter outbreaks among commercial turkeys were reported in many European, South American and Asian countries with a new sub-type isolated in the United States during 1996. The virus also causes swollen head syndrome (SHS) of chickens and outbreaks among commercial poultry have been reported from various parts of the world. Field outbreaks are exacerbated due to secondary bacterial pathogens that can induce air sacculitis, pericarditis, pneumonia and perihepatitis that may also lead to significant drops in egg production, egg peritonitis accompanied by ovary or oviduct regression. Although vaccines have been developed, outbreaks can also be traced to environmental spread of a vaccine-derived virus and the disease is exacerbated by bacterial infections. Although known for over 30 years and the application of different hygiene or vaccination strategies, aMPV still appears to be a problem in the field. Control measures are not always successful due to the fast horizontal spread of aMPV. Vaccine failures, virus evolution in response to vaccine pressure and the possible risk of reversion of vaccines to more virulent strains may interfere with conventional vaccination strategies. Consequently, the ongoing progress in the development of new generation of vaccines may provide new possibilities to better control aMPV in the field during the future.