Abstract in English:
ABSTRACT.- Peres M.F., Carrijo A.S., Higa A.H. & Oliveira J.M. 2006. [Serological evidence of avian pneumovirus infections in broiler flocks in counties of Mato Grosso do Sul.] Evidência sorológica de Pneumovírus aviário em lotes de frangos de corte em municípios de Mato Grosso do Sul. Pesquisa Veterinária Brasileira 26(4):254-258. Departamento de Zootecnia, Faculdade de Medicina Veterinária e Zootecnia, Universidade Federal de Mato Grosso do Sul (UFMS), Av. Filinto Müller 2443, Campo Grande, MS 79070-900, Brazil. E-mail: acarrijo@nin.ufms.br
Avian pneumovirus (APV) is an important respiratory pathogen of hens and broilers. Although it was not clearly elucidated whether APV may cause economical losses in broiler flocks, it is known that APV infection can induce specific antibody production on these birds, and these serological reactions may provide some information about the epidemiological status of the APV infections. This work was carried out in search for antibodies to APV in broiler flocks in counties of Mato Grosso do Sul. Five hundred and thirty six serum samples from 54 broiler flocks at 42 and 51 days of age were tested with a commercially available enzyme-linked immunosorbent assay (ELISA). The results showed that 330 samples (61.6%) were negative, 108 (20.1%) were suspect and 98 (18.3%) were considered positive for the presence to APV antibodies. Of all the flocks analyzed, 49 (90.7%) were considered either positive or suspect. The ELISA test demonstrated that there was a similar percentage of positive or suspect flocks among those flocks between 42 and 46 days of age, and among those between 47 and 51 days. No seasonal differences were observed, since the percentages of positive or suspect flocks either in summer or in winter months were similar. Most of the flocks were considered positive despite the type of broiler housing (conventional, environmental controlled or semi-controlled). It is concluded that there are strong evidences indicating circulation of APV in Mato Grosso do Sul. The percentages of positive flocks were similar regardless of the age groups of the birds examined, the type of broiler housing and the season when sampling was performed.
Abstract in Portuguese:
ABSTRACT.- Peres M.F., Carrijo A.S., Higa A.H. & Oliveira J.M. 2006. [Serological evidence of avian pneumovirus infections in broiler flocks in counties of Mato Grosso do Sul.] Evidência sorológica de Pneumovírus aviário em lotes de frangos de corte em municípios de Mato Grosso do Sul. Pesquisa Veterinária Brasileira 26(4):254-258. Departamento de Zootecnia, Faculdade de Medicina Veterinária e Zootecnia, Universidade Federal de Mato Grosso do Sul (UFMS), Av. Filinto Müller 2443, Campo Grande, MS 79070-900, Brazil. E-mail: acarrijo@nin.ufms.br
Avian pneumovirus (APV) is an important respiratory pathogen of hens and broilers. Although it was not clearly elucidated whether APV may cause economical losses in broiler flocks, it is known that APV infection can induce specific antibody production on these birds, and these serological reactions may provide some information about the epidemiological status of the APV infections. This work was carried out in search for antibodies to APV in broiler flocks in counties of Mato Grosso do Sul. Five hundred and thirty six serum samples from 54 broiler flocks at 42 and 51 days of age were tested with a commercially available enzyme-linked immunosorbent assay (ELISA). The results showed that 330 samples (61.6%) were negative, 108 (20.1%) were suspect and 98 (18.3%) were considered positive for the presence to APV antibodies. Of all the flocks analyzed, 49 (90.7%) were considered either positive or suspect. The ELISA test demonstrated that there was a similar percentage of positive or suspect flocks among those flocks between 42 and 46 days of age, and among those between 47 and 51 days. No seasonal differences were observed, since the percentages of positive or suspect flocks either in summer or in winter months were similar. Most of the flocks were considered positive despite the type of broiler housing (conventional, environmental controlled or semi-controlled). It is concluded that there are strong evidences indicating circulation of APV in Mato Grosso do Sul. The percentages of positive flocks were similar regardless of the age groups of the birds examined, the type of broiler housing and the season when sampling was performed.
Abstract in English:
Blood samples were obtained at slaughter from sixty 43 to 56 day old broilers, from each of 60 healthy flocks located in a region of high density poultry production. The flocks tested corresponded to approximately 10% of the total number existing in the region and were located within a radius of 50 km. All broilers had been vaccinated against Marek's disease atone day of age. Sera were tested in the immunodiffusion test for antibodies to avian reovirus (ARV), infectious bursal disease vírus (IBDV), fowl poxvirus (FPV), herpes virus of turkeys (HVT), avian adenovirus of groups 1 (AAV-1) and 2 (AAV-2). The sarne sera were tested in the micro serum neutralization test in plates for antibodies to infectious bronchitis virus (IBV) and infectious laryngotracheitis virus (ILTV), and for hemagglutination inhibition antibodies to Newcastle disease virus (NDV). Antibodies to ARV, detected in 2172 (63.6%) of 3418 sera, and to AAV-1, in 2701 (78.2%) of 3456 sera, were found in all 60 flocks, while antibodies to IBDV, in 3086 (89.4%) of 3452 sera, were found in only 57 of the sarne flocks. These results indicated that the three viruses are ubiquitous in broilers. Antibodies to FPV in 14 (0.5%) of 2935 sera, and to NDV in 6 (0.2%) of 3320 sera, were demonstrated in five of 59 and in one of 60 flocks, respectively, indicating that these two viruses occur only rarely. Antibodies to HVT, in 315 (9.0%) of 3384 sera, were detected in 39 of 60 flocks tested, suggesting poor serological response to vaccination and low field exposure to MDV. Antibodies to IBV, in 61 (2.1 %) of 2925 sera, were found in 12 of 57 flocks tested. However, in only one flock was the percentage of reactors significant (41 %); in the 11 flocks the percentage of broilers with antibody ranged from 1.7 to 16.1 %. Finally, no antibodies were found in 3491 sera from 60 flocks tested for AAV-2, nor in 3035 sera from 59 flocks when tested for ILTV, indicating that these two viruses do not exist in the geographical area tested. The significance of these findings is discussed.
Abstract in Portuguese:
Amostras de sangue foram obtidas ao abate de 60 frangos de corte, de 43 a 56 dias de idade, de cada uma de 60 granjas sem problemas sanitários aparentes localizadas em uma região de alta densidade de produção avícola. As granjas correspondiam a 10% do número total que existe na região e estavam localizadas em um raio de 50 km. Todos os frangos tinham sido vacinados contra a doença de Marek no primeiro dia de vida. Os soros foram avaliados no teste de imunodifusão para anticorpos para reovírus aviário (R V A), vírus da doença infecciosa da bursa (VDIB), vírus da bouba aviária (VBA), vírus herpes de perus (HVT), adenovírus aviário do grupo 1 (AVA-1) e do grupo 2 (A VA-2). Os mesmos soros foram examinados no microteste de soroneutralização em placas para anticorpos para o vírus da bronquite infecciosa (VBI) e o vírus da laringotraqueíte infecciosa (VLTI), bem como anticorpos inibidores da hemoaglutinação para o vírus da doença de Newcastle (VDN). Anticorpos para RVA, detectados em 2172 (63,6%) de 3418 soros, e para AVA-1, em 2701 (78,2%) de 3456 soros, foram demonstrados em todas as 60 granjas, enquanto que, anticorpos para o VDIB, em 3086 (89,4%) de 3452 soros, foram encontrados em somente 57 destas granjas. Estes resultados indicam que os três vírus são ubíquos em frangos de corte da região estudada. Anticorpos para o VBA em 14 (0,5%) de 2935 soros, para o VDN em seis (0,2%) de 3320 soros, foram encontrados em cinco de 59 e em uma de 60 granjas, respectivamente, indicando que esses dois vírus ocorrem apenas raramente. Anticorpos para HVT, em 315 (9,0%) de 3484 soros, foram detectados em 39 de 60 granjas testadas, sugerindo resposta sorológica pobre à vacinação e baixa exposição de campo ao vírus da doença de Marek. Anticorpos para o VBI, em 61 (2,1%) de 2925 soros, foram encontrados em 12 de 57 granjas testadas. Porém, em apenas uma granja a percentagem de reagentes era significativa (41 %); nas outras 11 granjas a percentagem de frangos com anticorpos variava de 1,7 a 16,1%. Finalmente, não foram detectados anticorpos em 3491 soros de 60 granjas testada para A VA-2, nem em 3035 soros de 59 granjas testadas para o VLTI, indicando que esses vírus não existem na área geográficas estudada. O significado de todos os achados é discutido.