Infecção experimental em carcarás (Caracara plancus, Miller, J. F., 1777) com Toxoplasma gondii (amostra ME49)
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Data
2007-07-20
Autores
Vitaliano, Sérgio Netto [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O presente trabalho objetivou estudar a susceptibilidade do carcará (Caracara plancus) frente à infecção experimental pela amostra ME49 de Toxoplasma gondii pela observação da sintomatologia clínica, análise dos parâmetros hematológicos, estudo da cinética de anticorpos IgG anti-T. gondii, e constatação da presença do parasito nos diversos tecidos utilizando a imunoistoquímica, imunofluorescência direta em tecidos, bioensaio em camundongos e PCR. Sete carcarás soronegativos para anticorpos anti-T. gondii foram separados em dois grupos: G1 (grupo infectado - 5 aves) e G2 (grupo controle - 2 aves). As aves do grupo G1 foram alimentadas durante três dias consecutivos com roedores Calomys callosus previamente infectados com T. gondii e as aves do grupo G2 foram alimentadas com roedores não infectados. As aves infectadas não apresentaram sintomas clínicos de toxoplasmose, tampouco alterações nos parâmetros hematológicos. Todas as aves infectadas soroconverteram. A soroconversão das aves experimentalmente infectadas ocorreu a partir do sétimo dia pós-infecção, os picos iniciais na produção de anticorpos IgG anti-T. gondii ocorreram entre 15 e 30 dias pós-infecção sendo que em seguida houve uma tendência de queda dos títulos de anticorpos. No momento da necropsia não foram encontradas lesões sugestivas da infecção por T. gondii. Não foi observado no exame histopatológico a presença do parasito nos diversos tecidos amostrados das aves infectadas, entretanto em uma das aves do grupo não infectado e sorologicamente negativa para anticorpos anti-T. gondii, foi encontrado um cisto tecidual na musculatura. Pelas técnicas de imunoistoquímica e imunofluorescência direta em tecidos o parasito foi encontrado em pequeno número em diversos tecidos, porém tanto nas aves do grupo infectado quanto nas aves do grupo controle. Utilizando o bioensaio em camundongos...
The present study aimed to evaluate the susceptibility of crested caracara (Caracara plancus) to experimental infection with ME49 strain of Toxoplasma gondii, through clinical symptoms, hematological parameter analysis, kinetics of specific IgG antibodies to T. gondii, and parasite detection by immunohistochemistry, direct immunofluorescence, bioassay, and PCR. Seven crested caracara, seronegative to T. gondii antibodies, were separated into two groups: G1 (infected group - 5 birds), and G2 (control group - 2 birds). G1 birds were fed during three successive days with Calomys callosus previously infected with T. gondii, and G2 birds were fed with non-infected rodents. The infected birds did not present clinical symptoms, nor significant changes in hematological parameters. All infected birds had antibody titers to T. gondii. IgG antibodies to T. gondii were first detected at 7 dpi, with production peaks between 15 and 30 dpi, which were followed by a sharp decrease in detectable antibodies. No gross lesions sugestive of T. gondii infection were observed. By histopatological examination, it was not possible to observe the presence of the parasite in the infected birds' organs, however, in one bird of the control group, a T. gondii tissue cyst was visualized in muscle. By immunohistochemistry and direct immunofluorescence, the parasite was found in small number in different organs, although in animals from both groups. The presence of T. gondii was confirmed in heart samples of two bioassayed birds, both from the infected group. In this study, the experimentally infected crested caracaras did not show clinical symptoms, alteration on hematological parameters and the parasite was found in small numbers in the organs of the birds, for these reasons the crested caracara were resistant to T. gondii infection.
The present study aimed to evaluate the susceptibility of crested caracara (Caracara plancus) to experimental infection with ME49 strain of Toxoplasma gondii, through clinical symptoms, hematological parameter analysis, kinetics of specific IgG antibodies to T. gondii, and parasite detection by immunohistochemistry, direct immunofluorescence, bioassay, and PCR. Seven crested caracara, seronegative to T. gondii antibodies, were separated into two groups: G1 (infected group - 5 birds), and G2 (control group - 2 birds). G1 birds were fed during three successive days with Calomys callosus previously infected with T. gondii, and G2 birds were fed with non-infected rodents. The infected birds did not present clinical symptoms, nor significant changes in hematological parameters. All infected birds had antibody titers to T. gondii. IgG antibodies to T. gondii were first detected at 7 dpi, with production peaks between 15 and 30 dpi, which were followed by a sharp decrease in detectable antibodies. No gross lesions sugestive of T. gondii infection were observed. By histopatological examination, it was not possible to observe the presence of the parasite in the infected birds' organs, however, in one bird of the control group, a T. gondii tissue cyst was visualized in muscle. By immunohistochemistry and direct immunofluorescence, the parasite was found in small number in different organs, although in animals from both groups. The presence of T. gondii was confirmed in heart samples of two bioassayed birds, both from the infected group. In this study, the experimentally infected crested caracaras did not show clinical symptoms, alteration on hematological parameters and the parasite was found in small numbers in the organs of the birds, for these reasons the crested caracara were resistant to T. gondii infection.
Descrição
Palavras-chave
Serology, Immunohistochemistry, Immunofluorescence, Biossay, Imuno-histoquímica, Imunofluorescência, Falconiformes, Bioensaio
Como citar
VITALIANO, Sérgio Netto. Infecção experimental em carcarás (Caracara plancus, Miller, J. F., 1777) com Toxoplasma gondii (amostra ME49). 2007. viii, 65 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2007.