title: Avian metapneumovirus subtypes circulating in Brazilian vaccinated and nonvaccinated chicken and turkey farms.
abstract: Avian metapneumovirus (AMPV) causes turkey rhinotracheitis and is associated with swollen head syndrome in chickens, which is usually accompanied by secondary infections that increase mortality. AMPVs circulating in Brazilian vaccinated and nonvaccinated commercial chicken and turkey farms were detected using a universal reverse transcriptase (RT)-PCR assay that can detect the four recognized subtypes of AMPV. The AMPV status of 228 farms with respiratory and reproductive disturbances was investigated. AMPV was detected in broiler, hen, breeder, and turkey farms from six different geographic regions of Brazil. The detected viruses were subtyped using a nested RT-PCR assay and sequence analysis of the G gene. Only subtypes A and B were detected in both vaccinated and nonvaccinated farms. AMPV-A and AMPV-B were detected in 15 and 23 farms, respectively, while both subtypes were simultaneously found in one hen farm. Both vaccine and field viruses were detected in nonvaccinated farms. In five cases, the detected subtype was different than the vaccine subtype. Field subtype B virus was detected mainly during the final years of the survey period. These viruses showed high molecular similarity (more than 96% nucleotide similarity) among themselves and formed a unique phylogenetic group, suggesting that they may have originated from a common strain. These results demonstrate the cocirculation of subtypes A and B in Brazilian commercial farms.
authors.affiliation: Department of Pathology, College of Veterinary Medicine, University of São Paulo, Avenida Professor Doutor Orlando Marques de Paiva, 87, Cidade Universitária, Butanā, CEP 05508-900, São Paulo, Brazil.
authors.forename: Jorge Luis
authors.initials: JL
authors.lastname: Chacón
authors.forename: Matheus
authors.initials: M
authors.lastname: Mizuma
authors.forename: Maria P
authors.initials: MP
authors.lastname: Vejarano
authors.forename: Didier
authors.initials: D
authors.lastname: Toquín
authors.forename: Nicolas
authors.initials: N
authors.lastname: Eterradossi
authors.forename: Devi P
authors.initials: DP
authors.lastname: Patnayak
authors.forename: Sagar M
authors.initials: SM
authors.lastname: Goyal
authors.forename: Antonio J Piantino
authors.initials: AJ
authors.lastname: Ferreira
mesh_terms: D000818:Animals; D001938:Brazil / Q000453:epidemiology; D002645:Chickens; D029121:Metapneumovirus / Q000145:classification* / Q000235:genetics / Q000276:immunology; D018184:Paramyxoviridae Infections / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D010802:Phylogeny; D014422:Turkeys; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D014765:Viral Vaccines