Chacón Jorge Luis, Mizuma Matheus, Vejarano Maria P, Toquín Didier, Eterradossi Nicolas, Patnayak Devi P, Goyal Sagar M, Ferreira Antonio J Piantino
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.
Avian Dis. 2011 Mar;55(1):82-9. doi: 10.1637/9501-081310-Reg.1.
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.
禽偏肺病毒（AMPV）可引起火鸡鼻气管炎，并与鸡的肿头综合征有关，通常伴有继发性感染，从而增加死亡率。使用一种通用逆转录酶（RT）-PCR检测方法对巴西接种疫苗和未接种疫苗的商业养鸡场和火鸡场中传播的AMPV进行了检测，该方法可检测AMPV的四种公认亚型。对228个存在呼吸和生殖障碍的养殖场的AMPV状况进行了调查。在巴西六个不同地理区域的肉鸡场、蛋鸡场、种鸡场和火鸡场中检测到了AMPV。使用巢式RT-PCR检测方法和G基因序列分析对检测到的病毒进行了亚型鉴定。在接种疫苗和未接种疫苗的养殖场中均仅检测到A和B亚型。分别在15个和23个养殖场中检测到了AMPV-A和AMPV-B，在一个蛋鸡场中同时发现了这两种亚型。在未接种疫苗的养殖场中检测到了疫苗病毒和野毒株。在五个案例中，检测到的亚型与疫苗亚型不同。在调查期的最后几年主要检测到野毒株B亚型。这些病毒之间表现出高度的分子相似性（核苷酸相似性超过96%），并形成了一个独特的系统发育群，表明它们可能起源于同一毒株。这些结果证明了A和B亚型在巴西商业养殖场中的共同传播。
