RESUMO

The present study aimed to investigate the occurrence of Mycoplasma synoviae (MS), M. gallisepticum (MG), Ornitobacterium rhinotracheale (OR), Avibacterium paragallinarum (AP), Pasteurella multocida (PM) and Infectious Bronchitis Virus (IBV) in laying hens with respiratory clinical signs in two phases of production. 140 tracheal swabs and 140 blood samples were collected from laying hens in the rearing and production phases, the chickens belonged to six farms (A-F) located in the state of São Paulo, Brazil. The samples were analyzed by PCR for MG, MS, OR, AP, PM and IBV and by ELISA for MG and MS. The highest frequencies observed by PCR were for MS at farms B and C with 95 and 100% positivity, followed by MG at farms D and E with 35% and 65%, IBV with 35% at farm F and ORT with 15% at farm A. All flocks were positive for MG and MS in serology. Although MG and IBV have been detected, this can be explained by the vaccination protocols, since live attenuated vaccines are widely used for immunization against these pathogens. It was also possible to detect OR and AP thorugh PCR in some flocks. The occurrence of several etiological agents that cause respiratory diseases in laying hens was confirmed by PCR and serology, with MS being the most prevalent and being present in all farms studied.(AU)

Assuntos

RESUMO

The present study aimed to investigate the occurrence of Mycoplasma synoviae (MS), M. gallisepticum (MG), Ornitobacterium rhinotracheale (OR), Avibacterium paragallinarum (AP), Pasteurella multocida (PM) and Infectious Bronchitis Virus (IBV) in laying hens with respiratory clinical signs in two phases of production. 140 tracheal swabs and 140 blood samples were collected from laying hens in the rearing and production phases, the chickens belonged to six farms (A-F) located in the state of São Paulo, Brazil. The samples were analyzed by PCR for MG, MS, OR, AP, PM and IBV and by ELISA for MG and MS. The highest frequencies observed by PCR were for MS at farms B and C with 95 and 100% positivity, followed by MG at farms D and E with 35% and 65%, IBV with 35% at farm F and ORT with 15% at farm A. All flocks were positive for MG and MS in serology. Although MG and IBV have been detected, this can be explained by the vaccination protocols, since live attenuated vaccines are widely used for immunization against these pathogens. It was also possible to detect OR and AP thorugh PCR in some flocks. The occurrence of several etiological agents that cause respiratory diseases in laying hens was confirmed by PCR and serology, with MS being the most prevalent and being present in all farms studied.

Assuntos

RESUMO

A farm with 3,000 free-range hens between 24 and 65 weeks of age was investigated. These hens were separated in small flocks of 400 to 700 birds, presenting 10 to 23% egg production reduction. Twenty serum samples were collected during the period of drop in egg production and three weeks later for the investigation of Mycoplasma synoviae (MS), M. gallisepticum (MG) and Infectious Bronchitis Virus (IBV) antibodies using ELISA. At the time of the second collection, egg production had resumed to normal levels; however, with 10.23% of the eggs showed eggshell abnormalities limited to the apex. Eggshell strength was significantly different between normal and those with eggshell apex abnormalities, but not other egg-quality parameters. ELISA tests showed that MS and IBV titers increased during the evaluated period. MS infection was confirmed by culture and by PCR of tracheal swabs. All samples were negative for MG by ELISA and PCR. Further studies with larger samples to ensure the occurrence of this disease in industrial layer flocks in Brazil are under way.(AU)

Assuntos

RESUMO

A farm with 3,000 free-range hens between 24 and 65 weeks of age was investigated. These hens were separated in small flocks of 400 to 700 birds, presenting 10 to 23% egg production reduction. Twenty serum samples were collected during the period of drop in egg production and three weeks later for the investigation of Mycoplasma synoviae (MS), M. gallisepticum (MG) and Infectious Bronchitis Virus (IBV) antibodies using ELISA. At the time of the second collection, egg production had resumed to normal levels; however, with 10.23% of the eggs showed eggshell abnormalities limited to the apex. Eggshell strength was significantly different between normal and those with eggshell apex abnormalities, but not other egg-quality parameters. ELISA tests showed that MS and IBV titers increased during the evaluated period. MS infection was confirmed by culture and by PCR of tracheal swabs. All samples were negative for MG by ELISA and PCR. Further studies with larger samples to ensure the occurrence of this disease in industrial layer flocks in Brazil are under way.

Assuntos

RESUMO

Newcastle disease is characterized by respiratory manifestations in association with nervous and/or digestive symptoms. Its prevention is done by vaccination with live attenuated (lentogenic strains) and/or killed vaccines. The lentogenic strains can lead to strong post-vaccination reaction, principally due to the presence of other pathogenic agents. Among them, Mycoplasma synoviae is worldwide important, mainly in Brazil. The dissemination of this agent in poultry flocks has been achieved due to difficulties in diagnosis and disease reproduction, virulence variations among different M.synoviae strains, and attribution of typical M.synoviae disease manifestation to other disease agents. This experimental study in SPF chicks (Gallus gallus), previously infected by M.synoviae and thereafter vaccinated against Newcastle disease, was done with the objective of evaluating M.synoviae pathogenicity through assessment of post-vaccinal respiratory reactions and serologic responses to Newcastle disease virus vaccine in the absence of environmental factors. A total of 86 three days old chicks were used, being 57 infected by eye and nostril drop, with chicken activated M. synoviae strain WVU 1853. Seven days later, 21 mycoplasma infected birds plus 29 not mycoplasma infected ones were vaccinated against Newcastle disease. As results, the not infected and vaccinated birds yielded, significantly, higher and longer lasting serologic responses to Newcastle disease vaccine virus than those infected and vaccinated. Similarly, the infected and vaccinated birds yielded lower serologic reactions to M.synoviae than those only mycoplasma infected. No post-vaccinal respiratory reaction was observed in the vaccinated birds.

A doença de Newcastle é caracterizada por manifestações respiratórias associadas a sintomas nervosos e/ou digestivos. Sua prevenção é feita pela vacinação com vacinas vivas atenuadas (cepas lentogênicas) e/ou inativadas. As cepas lentogênicas podem determinar acentuada reação pós-vacinal, principalmente na presença de outros patógenos. Entre eles, o Mycoplasma synoviae tem importância mundial, principalmente no Brasil. A disseminação deste agente nos planteís avícolas tem sido facilitada, devido a dificuldades de reprodução e diagnóstico da doença em aves, variação de virulência entre as diferentes cepas de M.synoviae e atribuição a outros patógenos de manifestação típica da micoplasmose por M.synoviae. Este estudo experimental em aves (Gallus gallus) SPF, previamente infectadas por M.synoviae e depois vacinadas contra Newcastle, foi realizado com objetivo de avaliar a patogenicidade do M.synoviae pela obtenção dareação respiratória pós-vacinal e a resposta sorológica para o vírus vacinal da doença de Newcastle, na ausência de fatores ambientais. Um total de 86 aves, com três dias de idade foram utilizadas, sendo 57 infectadas via ocular e intranasal, com cepa MS WVU 1853, ativada em galinhas. Sete dias depois, 21 aves infectadas por micoplasma e 29 não infectadas foram vacinadas contra a doença de Newcastle. Como resultados, aves não infectadas e vacinadas produziram resposta sorológica para o vírus vacinal da doença de Newcastle, significativamente mais elevada e mais duradora que aquelas infectadas e vacinadas. Igualmente, aves infectadas e vacinadas produziram reações sorológicas para M.synoviae mais baixa, que aquelas apenas infectadas. Não foram observadas reações respiratórias pós-vacinal nas aves vacinadas.

Assuntos