Distribuição de Mycobacterium avium subespécie paratuberculosis em órgãos de camundongos C57BL/6 experimentalmente infectados

• Ano de defesa: 2012
• Autor(a) principal: Schwarz, David Germano Gonçalves
• Orientador(a): Moreira, Maria Aparecida Scatamburlo
• Banca de defesa: Fietto, Luciano Gomes
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Medicina Veterinária
• Departamento: Biotecnologia, diagnóstico e controle de doenças; Epidemiologia e controle de qualidade de prod. de
• País: BR
• Palavras-chave em Português: Paratuberculosis; Murino; Técnica molecular
• Palavras-chave em Inglês: Paratuberculosis; Murine; Molecular technique
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::MEDICINA VETERINARIA PREVENTIVA::DOENCAS INFECCIOSAS DE ANIMAIS
• Link de acesso: http://locus.ufv.br/handle/123456789/5166

Mycobacterium avium subspecies paratuberculosis (MAP) is the etiological agent of paratuberculosis, a disease which causes chronic granulomatous enteritis preferably in domestic and wild ruminants. It is characterized by intermittent diarrhea, progressive weight loss and reduced milk production. The major route of transmission is the ingestion of food and water contaminated by feces of infected animals. It is considered a disease of high economic importance, because of losses in livestock and importance in human health, since there is evidence of possible correlation of MAP with Crohn's disease. Although previous researches have contributed to advances in the diagnosis of subclinical MAP in animals, there is a lack of studies concerning the correct understanding of its pathophysiology. Thus, the aim of this study was to investigate the distribution of MAP by means of the histology and nested-PCR techniques in organs of C57BL/6 mice infected with MAP66115-98 strain at a dose of 3 x 108 CFU /mL intraperitoneally (IP). It was applied 250μl of inoculum in 20 mice, and it was applied saline phosphate buffer (PBS) in eight control species. The animals were euthanized at 30, 60, 90 and 120 days post-inoculation, and fragments of spleen, liver, colon, ileum and Peyer's patches of five mice and two control, for each period of time, were performed molecular and histopathological evaluations. Although it was not found histologic lesions in sections stained by Hematoxylin Eosin, there was a positive staining for two Peyer s patches referring to 90 and 120 days after inoculation, stained by Ziehl-Neelsen. Among the collected organs, 64.9% were positive by molecular technique. The spleen (0.85), colon (0.75) and liver (0.60) had the highest proportion of positive regardless of the evaluation period. Taking into consideration the time after inoculation, the spleen had a higher proportion of positive results after 60 days of infection (1.00), remaining stable until 120 days. The colon had a higher proportion at 30 days (1.00) and drastically reduced to 90 days (0.40). The liver ranged between 0.40 and 0.80 during the four periods of evaluation and the Ileum showed positivity ratio equal to 0.80 only at 120 days of infection. Moreover, Peyer's patches did not vary significantly (0.40) from day 60, remaining with the lowest ratio among the organs studied. The assessment of the probability of infection of an organ relative to another was obtained by the Relative Risk, where the highest values were observed in the ratio of spleen/Peyer's patches (2.00), colon/Peyer's patches (1.74), spleen/ileum (1.54) and spleen/liver (1.40). The highest odds ratio values were observed in the spleen/Peyer s patches (7.56), spleen/ileum (4.64), spleen/liver (3.78), and colon/ileum (2.45). However, among all the established associations, only the relations spleen / ileum and spleen / Peyer's patches were statistically significant at the level of 95%, showing that the spleen was the organ with higher risk and chances of positivity in relation to the ileum and Peyer's patches. Thus, these results can contribute to better understanding of the distribution of MAP in experimental models during the course of systemic infection, being this the first study to correlate the infective capacity of the strain MAP66115- 98 in C57BL/6 mice with a distribution in different organs after inoculation by intraperitoneal route.