Relação parasito-hospedeiro na infestação artificial de Oryctolagos cuniculus (Linnaeus, 1758) (Lagomorpha: Ochotonidae) por Amblyomma cajennense (Fabricius, 1787) (Acari: ixodidae)
| Ano de defesa: | 2005 |
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| Autor(a) principal: | |
| Orientador(a): | |
| Banca de defesa: | |
| Tipo de documento: | Tese |
| Tipo de acesso: | Acesso aberto |
| Idioma: | por |
| Instituição de defesa: |
Universidade Federal de Minas Gerais
UFMG |
| Programa de Pós-Graduação: |
Não Informado pela instituição
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| Departamento: |
Não Informado pela instituição
|
| País: |
Não Informado pela instituição
|
| Palavras-chave em Português: | |
| Link de acesso: | http://hdl.handle.net/1843/SSLA-7TXQNV |
Resumo: | The present study had as its general objective, the evaluation of the immunological aspects of the parasite-host relationship in rabbits artificially infested by Amblyomma cajennense and to begin the search for susceptible antigens to be used in the control of that parasite. For such reason, three different experiments were effected: (1) in the first experiment, the development of acquired resistance in rabbits submitted to the artificial infections by larvae, nymphs and adults of A. cajennese were studied. The rabbits only became resistant to parasitism for larvae starting from the third infestation, at which time the medium rate of recovery was significantly reduced. No significant effect on the medium rate of ecdisis of the recovered larvae took place. The modal drop-off day of larvae engorged increased as of the third infestation. In the rabbitsinfested by nymphs, as of the first infestation, a significant reduction of body weight of the recovered parasites was observed; however, just beginning with the third infestation, a significant reduction could be verified in the medium rate of recovery. In the resistance observed in the rabbits infested by adults, it was significant as of the second infestation,affecting most of the parasitic and reproductive parameters that were observed. The data suggest the resistance occurrence to the infestation for A. cajennense in rabbits that was more evident against to the adult stage of that ixodid. (2) in the second experiment, the humoral and cellular response and resistance development to the parasitism in rabbits immunized with EGS of females of A. cajennense or submitted to the artificial infestation by males and females of that ixodid species was evaluated. The rabbits submitted to three consecutive infestations became resistant as of the second infestation, there being a larger impact observed on the parasitic parameters that were appraised. The immunization with EGS did not alter the parasitic performance of the ixodids fed in the vaccinated animals; however, it presented deleteriouseffect in some reproductive parameters that were appraised. Specific anti-EGS antibodies could be recognized in the serums of the infested animals and immunized animals. The values of absorption of IgG anti-EGS in the infested animals increased as of the second infestation and they remained high, up to the 42nd experiment. In the immunized animals, those values were considerably higher, increasing as of the 7th day after the first immunization. No correlation was observed between resistance degree and level of anti-EGS antibodies. The istopathologicalanalysis revealed the occurrence of an infiltrated inflammation in the site of fixation of the ixodids that was significantly more intense in the rabbits immunized with EGS and in those submitted to three consecutive infestations. The rate of parasitism was not correlated with thelesion degree in the skin in any of the appraised experimental groups. (3) finally, in the third experiment, the humoral response and the resistance development were evaluated in rabbits immunized with a derivate extract of Genés glands (EGG) of A. cajennense and in rabbits successively infested with females and males of that ixodídeous species. The infested rabbits became resistant as of the second infestation, it being that the parasitic parameters were the most affected for the immune response of the animals. The immunization of rabbits of the GGG group with the extract of Genés glands did not present any significant effect on the parasitic and reproductive variables that were observed in the recovered ixodids. The medium values of absorbance of the IgG anti-EGG in the rabbits successively infested stayed low during the whole experiment, though, they presented a small increase as of the third infestation. Theimmunization of the animals with EGG was efficient in inducing the production of specific antibodies against this antigen. The medium values of absorbance of IgG anti-EGG in the immunized animals increased as of the 7th day following the immunization and surprisingly,they reached maximum indexes after the artificial infestation. However, despite that, the humoral response reached by the animals it was not capable of protecting them from the parasitic challenge |