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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Avalia??o da biologia e da infec??o por Rickettsia rickettsii (Rickettsiales: Rickettsiaceae) em Haemaphysalis leporispalustris (Acari: Ixodidae) utilizando coelho dom?stico como hospedeiro. / Evaluation of Haemaphysalis leporispalustris (Acari: Ixodidae) biology and infection for Rickettsia rickettsii (Rickettsiales: Rickettsiaceae) using domestic rabbit as host

Freitas, Luciana Helena Teixeira de 21 May 2007 (has links)
Made available in DSpace on 2016-04-28T20:16:23Z (GMT). No. of bitstreams: 1 2007-Luciana Helena Teixeira de Freitas.pdf: 967474 bytes, checksum: 42db4aba518b754de5ef670fd3af5b94 (MD5) Previous issue date: 2007-05-21 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / With the aim to increase data about the biology of Haemaphysalis leporispalustris in Brazil, two studies were conduced. The first experiment evaluated biological parameters of nymphs of H. leporispalustris during and after the parasitism with the aim to relating those with appearance of males or females. The male parasitism is also evaluated. We tried stipulated the period of minimum and maximum survival of males on the host and the influence of number or longevity of males in the reproductive capacity of females. The second experiment approached the biological acting of the tick front to the infection for Rickettsia rickettsii, causal agent of the Brazilian Spotted Fever. In the first experiment, the engorged nymphs that changed for males were lighter and presented shorter parasitic period (p <0,05) that the ones that changed for females. The sexual ratio (SR) was established in agreement with the parasitic period. Engorged nymphs of shorter parasitic period (5 and 6 days) created a larger proportion of males (1:0 and 1,70: 1, respectively) that the nymphs of longer parasitic period (9 to 10 days, and SR of 1:3,07 and 1: 4,60, respectively). Already the nymphs that engorged in 7 to 8 days, created males and females in proportion of 1: 1,73 and 1:1,67, respectively.Only the larval hatching was influenced by the number of live males. The weight of the engorged females was more influenced by the host resistance than for the number of live males. In the second experiment, alterations in the biological parameters of H. leporispalustris exposed to the R. rickettsii infection were appraised during the parasitic and no parasitic phase of larvae, nymphs and females ticks. Experimental groups were generated by fed on R. rickettsii infected rabbits, during larvae, nymphs and adult phase. Other group was created through co-feeding of R. rickettsii positive males with larvae in healthy rabbits. The tick s group directly fed in inoculated animals suffered larger effect of the infection on the biological parameters, with increase of the parasitic period and mortality, and decrease of the weight and oviposition period. The group infected in the nymph phase generated lighter females, that produced less eggs than didn't developed appropriately (low hatching). The larvae infected by co-feeding with infected males group represents the closest model to the than it happens in the natural condition. This group presented heavier larvae and smaller mortality of larvae and engorged nymphs, in relation to the control group. The efficiency in the ecdisis of nymphs was greater, and even the engorged females presenting smaller weight, they obtained IER upper to the control group. / Com o objetivo de acrescentar dados sobre a bioecologia de Haemaphysalis leporispalustris e a Febre Maculosa no Brasil, dois estudos foram conduzidos. O primeiro experimento avaliou par?metros biol?gicos de ninfas de H. leporispalustris durante e ap?s o parasitismo com o objetivo de relacion?-los com o surgimento de machos ou f?meas e o parasitismo do sexo masculino. Procurou-se estipular qual o per?odo de sobreviv?ncia m?nima e m?xima de machos sobre o hospedeiro e a influ?ncia do n?mero e da longevidade dos machos sobre a capacidade reprodutiva das f?meas. O segundo experimento abordou o desempenho biol?gico do ixod?deo frente ? infec??o por Rickettsia rickettsii, agente causal da Febre Maculosa Brasileira. No primeiro experimento, as ninfas ingurgitadas mais leves mudaram para machos e apresentaram per?odo parasit?rio mais curto (p<0,05) do que as que mudaram para f?meas. A raz?o sexual (RS) foi estabelecida de acordo com o per?odo parasit?rio. Ninfas ingurgitadas de per?odo parasit?rio mais curto (5 e 6 dias) deram origem a uma maior propor??o de machos (1:0 e 1,70: 1, respectivamente) que as ninfas de per?odo parasit?rio mais longo (9 a 10 dias, e RS de 1:3,07 e 1: 4,60, respectivamente). J? as ninfas que se ingurgitaram em 7 a 8 dias, deram origem a machos e f?meas em propor??o de 1: 1,73 e 1:1,67, respectivamente. Somente a eclos?o larval foi influenciada pelo n?mero de machos vivos, sendo que o peso da f?mea ingurgitada foi influenciado mais pela resist?ncia do hospedeiro do que pelo n?mero de machos vivos. No segundo experimento, altera??es no desempenho biol?gico de H. leporispalustris expostos ? infec??o por R. rickettsii, foram avaliadas durante a fase parasit?ria e n?o parasit?ria de larvas, ninfas e f?meas do carrapato. Foram gerados grupos de carrapatos infectados durantes as fases de larva, ninfa e adulto, alimentados em coelhos inoculados com R. rickettsii e um grupo de larvas infectadas atrav?s de co-parasitismo com machos positivos para R. rickettsii. Os grupos de carrapatos diretamente alimentados em animais inoculados sofreram maior efeito da infec??o sobre o desempenho biol?gico, com aumento do per?odo parasit?rio e da mortalidade, e diminui??o do peso e do per?odo de postura. O grupo infectado na fase de ninfa gerou f?meas mais leves, que produziram menos ovos que por sua vez n?o se desenvolveram adequadamente (baixa eclos?o). O grupo experimental gerado pelo co-parasitismo entre larvas e machos representou o modelo mais pr?ximo ao que ocorre na condi??o natural. Este grupo apresentou larvas mais pesadas e menor mortalidade de larvas e ninfas ingurgitadas em rela??o ao controle. A efici?ncia na ecdise de ninfas foi maior e mesmo as f?meas ingurgitadas apresentando menor peso, obtiveram IER superior ao do grupo controle.

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