RESUMO
Precocious lines of Eimeria acervulina "Cu" and "I" strains were obtained after 25 passages of oocysts in chickens that showed a shortening of the prepatent period for first oocyst output from 96 h to 81 and 82 h, respectively. Both precocious lines were evaluated for pathogenicity using as criteria weight gain, lesion score and total oocyst production. Infection of the "Cu" precocious line in chickens showed a high weight gain, low lesion score and low oocyst production, when compared to parent strain infected chickens. However, the results did not show a significant difference in relation to the criteria used above for the E. acervulina "I" precocious line when compared to its parent strain. This suggests a low degree of attenuation for the "I" strain but good attenuation for the precocious "Cu" line. The histopathological observations of chickens infected with the E. acervulina "Cu" parent strain and precocious line, comparing life cycle and intestinal lesions, showed: (1) parasite stages only in the border cells of infected chicken intestinal villi, for the precocious line; (2) parasite stages in the border cells of the intestinal villi and submucosa cells near the Lieberkühn glands of the intestine; and (3) high degree of inflammatory cells around the parasites in chickens infected with the parent strain. The "Cu" strain was also characterized for sensitivity against eight anticoccidial drugs. Sensitivity was observed for four anticoccidial drugs and partial resistance for four other drugs, although the strain had never had previous contact with anticoccidial drugs, suggesting the presence of a natural resistance factor. This Brazilian E. acervulina "Cu" precocious line showed attenuation for pathogenicity in chickens, suggesting that it could be a suitable strain for use as a live vaccine in Brazil.
Assuntos
Galinhas , Coccidiose/veterinária , Eimeria/crescimento & desenvolvimento , Enteropatias Parasitárias/veterinária , Doenças das Aves Domésticas/parasitologia , Animais , Peso Corporal , Brasil , Coccidiose/imunologia , Coccidiose/parasitologia , Coccidiose/patologia , Coccidiostáticos/farmacologia , Resistência a Medicamentos , Eimeria/metabolismo , Eimeria/patogenicidade , Fezes/parasitologia , Histocitoquímica/veterinária , Enteropatias Parasitárias/imunologia , Enteropatias Parasitárias/parasitologia , Enteropatias Parasitárias/patologia , Intestinos/imunologia , Intestinos/parasitologia , Intestinos/patologia , Contagem de Ovos de Parasitas/veterinária , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/patologia , Distribuição Aleatória , Organismos Livres de Patógenos Específicos , VirulênciaRESUMO
De maio a novembro/94 foram escolhidas ao acasso 67 propriedades na regiao Dos Lagos, no Estado do Rio de Janeiro para estudar a ocorrência e a prevalência de fasciola hépatica em bovinos. Para tal objetivo, 20 por ciento do total de animais de cada propriedade foram examinados, através de técnica de tamises sucessivos. No final do experimento, registrou-se uma nova ocorrência de f. hépatica em bovinos nascidos e criados nesta regiao, calculando-se a prevalência de 6,0 por ciento
