Rotavírus bovino: fatores de risco, prevalência e caracterização antigênica de amostras em rebanhos leiteiros no estado de São Paulo
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Data
2011-08-01
Autores
Freitas, P. P. S.
Uyemura, S. A.
Silva, D. G.
Samara, Samir Issa [UNESP]
Buzinaro, Maria da Glória [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal de Minas Gerais (UFMG), Escola de Veterinária
Resumo
O estudo de prevalência da infecção por rotavírus em bezerros abrangeu 51 rebanhos leiteiros, escolhidos ao acaso, localizados em uma região produtora de leite do estado de São Paulo. Entre 31 de maio e 20 de outubro de 2003, foram colhidas 103 amostras de fezes de bezerros com diarreia e 308 amostras de animais sem diarreia, com idade entre um e 45 dias. As amostras foram analisadas pelas técnicas de ensaio imunoenzimático (EIE) e eletroforese em gel de poliacrilamida (PAGE). Pelo EIE foi observada prevalência de rotavírus de 21,6% (11/51) nos rebanhos e 6,7% (27/404) nos bezerros. Foram diagnosticados animais infectados por rotavírus tanto em bezerros diarreicos (18,4%; 19/103) quanto em bezerros assintomáticos (2,7%; 8/301). A maior frequência de infecção foi determinada em bezerros com idade entre um e 15 dias, sendo estabelecida uma relação inversa entre a frequência de positividade e a idade dos animais (P<0,05). Além da idade, o sistema de alimentação - fornecimento manual do leite ou bezerro com a mãe, o tipo de instalação - baias individuais ou baias coletivas - e o tamanho do rebanho -, número de matrizes foram fatores que influenciaram significativamente a frequência da infecção (P<0,05). O RNA extraído de 27 amostras pelo PAGE foi classificado em sete eletroferótipos, indicando grande diversidade genômica de rotavírus. A genotipagem das amostras positivas para rotavírus foi realizada pelo método de transcrição reversa-reação da polimerase em cadeia, destacando a presença de infecções pelos genótipos G6P[5] e G10P[11].
The study on rotavirus infection prevalence in calves was undertaken in 51 dairy cattle herds, randomly selected, in a dairy area in the state of São Paulo. One hundred and three samples of feces from calves with diarrhea and 308 samples of feces from calves free from the disease, age ranging from 1 to 45 days, were collected from May 31st to October 20th 2003. Stool samples were analyzed through immunoenzymatic assay techniques (IEA) and polyacrylamide gel electrophoresis (PAGE). Rotavirus prevalence rate of 21.6% (11/51) was detected by IEA in cattle herds and 6.7% (27/404) in calf population. Rotavirus infection was diagnosed in calves with diarrhea (18.4%; 19/103) and in clinically healthy calves (2.7%; 8/301). The highest infection frequency was found in calves aged 1 to 15 days. There is an inverse relationship between positive frequency and age of animals (P<0.05). Factors which may affect rotavirus prevalence in herds, such as type of meals (manual milk supply or calf with dame), enclosure (individual or collective pens), herd size (number of matrixes) and age have been analyzed by the chi-square test, and significantly affected infection frequency (p<0.05). RNA from 27 positive samples by PAGE were classified in seven electrophorotypes and showed the rotavirus' extensive genomic diversity. Rotavirus positive samples genotyping was undertaken through the reverse transcription-polymerase chain reaction (RT-PCR), underpinning infections by special genotypes G6P[5] and G10P[11].
The study on rotavirus infection prevalence in calves was undertaken in 51 dairy cattle herds, randomly selected, in a dairy area in the state of São Paulo. One hundred and three samples of feces from calves with diarrhea and 308 samples of feces from calves free from the disease, age ranging from 1 to 45 days, were collected from May 31st to October 20th 2003. Stool samples were analyzed through immunoenzymatic assay techniques (IEA) and polyacrylamide gel electrophoresis (PAGE). Rotavirus prevalence rate of 21.6% (11/51) was detected by IEA in cattle herds and 6.7% (27/404) in calf population. Rotavirus infection was diagnosed in calves with diarrhea (18.4%; 19/103) and in clinically healthy calves (2.7%; 8/301). The highest infection frequency was found in calves aged 1 to 15 days. There is an inverse relationship between positive frequency and age of animals (P<0.05). Factors which may affect rotavirus prevalence in herds, such as type of meals (manual milk supply or calf with dame), enclosure (individual or collective pens), herd size (number of matrixes) and age have been analyzed by the chi-square test, and significantly affected infection frequency (p<0.05). RNA from 27 positive samples by PAGE were classified in seven electrophorotypes and showed the rotavirus' extensive genomic diversity. Rotavirus positive samples genotyping was undertaken through the reverse transcription-polymerase chain reaction (RT-PCR), underpinning infections by special genotypes G6P[5] and G10P[11].
Descrição
Palavras-chave
Calf, Rotavirus, Diarrhea, Risk factor, genotyping, Bezerro, Rotavírus, Diarréia, Fatores de risco, genotipagem
Como citar
Arquivo Brasileiro de Medicina Veterinária e Zootecnia. Universidade Federal de Minas Gerais, Escola de Veterinária, v. 63, n. 4, p. 820-827, 2011.