Lyme disease is the most common vector-borne infection in the Western world with an annual incidence usually in excess of 100 cases per 100 000 people in temperate areas of the United States and Europe. Same as other infectious diseases, Lyme borreliosis wreaks havoc on the host they have invaded. B. burgdorferi, the causative agent of this disease, circulates among wildlife vertebrate hosts and Ixodes tick vectors but may sometimes infect humans. Its natural enzootic cycle usually occurs as follows: The larval/nymphal stage tick feeds on an infected host. During this engorgement, the spirochetes reach the tick gut and stay confined to it. After the tick molts into the next developmental stage, it finds a second host. The new bloodmeal triggers the spirochetes to multiply within the gut and traverse the gut endothelium in a highly organized manner. They finally disseminate through the hemocoel up to the tick salivary glands and into the new host. We studied whether B. burgdorferi is capable of reaching the tick salivary glands during the first infective feeding period in uninfected ticks.

Made available in DSpace on 2016-04-28T20:15:31Z (GMT). No. of bitstreams: 1 2008 - Charles Passos Rangel.pdf: 970968 bytes, checksum: 8211b14a033b6089d8ed8bbdef93fe27 (MD5) Previous issue date: 2008-08-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Artificial feeding is an important tool, as an option to minimize the use of animals in scientific experiments, providing study of the transmission of bioagentes in the absence of vertebrate host. The objectives of this study were artificially food through capillary tubes females partially engorged of the tick Rhipicephalus (Boophilus) microplus previously fed on cattle and to check the influence of the technique in the biological aspects of non-parasitic phase this species. Females weighing between 40,6 and 69,7 milligrams were separated into four groups of homogeneous weight, with 10 females in each and set on trays of styrofoam with double-sided tape. For artificial feeding tubes of microhematocrit containing blood citrated cattle were placed on the apparatus mouthpiece of ticks. The groups were fed by six, 12, 24, 36 hours, being kept under temperature of 27 ? 1 ? C and humidity above 80%. After artificial feeding, the ticks were weighed to verify the ingestion of blood. To monitoring the biological aspects, the ticks were set in Petri dishes, and kept in the same controled temperature and humidity, describe above. The control group was formed by engorged females from cattle, being kept in the same conditions of temperature and humidity of the groups artificially fed. For statistical analysis was used variance analysis and Tukey's test with a significance level of 5%, for comparisons of means. The average weights acquired in milligrams were 12.33 ? 15.17; 33.41 ? 21.27; 67.53 ? 27.57; 79.47 ? 45.53 in groups 6, 12, 24, 36 hours, respectively. The two groups exposed for less time to capillaries, showed statistical difference compared with the gain average of weight of the group of 36 hours. From 24 hours of feeding was observed significant difference between the biological aspects of the groups artificially fed, except for the posture period. Although the females artificially fed through capillary tubes have not reached full engorgiment, the findings show that the technique did not presented deleterious effect on the biological aspects of this species. / Alimenta??o artificial ? uma ferramenta importante, por constituir op??o para minimizar o uso de animais na experimenta??o cient?fica propiciando estudo da transmiss?o de bioagentes na aus?ncia do hospedeiro vertebrado. Os objetivos deste estudo foram alimentar artificialmente, por meio de tubos capilares, f?meas parcialmente ingurgitadas do carrapato Rhipicephalus (Boophilus) microplus previamente alimentadas em bovinos e verificar a influ?ncia da t?cnica, nos aspectos biol?gicos da fase n?o-parasit?ria desta esp?cie. F?meas pesando entre 40,6 e 69,7 miligramas foram separadas em quatro grupos de peso homog?neo, com 10 f?meas cada e fixadas em bandejas de isopor com aux?lio de fita dupla face. Para alimenta??o artificial, tubos de microhemat?crito contendo sangue bovino citratado foram posicionados sobre o aparelho bucal dos carrapatos. Os grupos foram alimentados por 6, 12, 24, 36 horas, sendo mantidos em estufa, ? temperatura de 27 ? 1?C e umidade superior a 80%. Ap?s alimenta??o artificial, os carrapatos foram pesados para verifica??o da ingest?o de sangue. Para acompanhamento dos aspectos biol?gicos, os carrapatos foram fixados em placas de Petri, e incubados nas mesmas condi??es de temperatura e umidade descritas acima. O grupo controle foi formado a partir de f?meas ingurgitadas oriundas de bovinos infestados experimentalmente, mantidas nas mesmas condi??es de temperatura e umidade dos grupos alimentados artificialmente. Para an?lise estat?stica utilizou-se an?lise de vari?ncia e teste de Tukey com n?vel de signific?ncia 5%, para compara??es das m?dias. Os pesos m?dios em miligrama adquiridos foram 12,33?15,17; 33,41?21,27; 67,53?27,57; 79,47?45,53 nos grupos 6, 12, 24, 36 horas, respectivamente. Os dois grupos expostos por menos tempo aos capilares apresentaram diferen?a estat?stica em rela??o ao ganho m?dio de peso do grupo de 36 horas. A partir de 24 horas de alimenta??o foi observada diferen?a significativa entre os aspectos biol?gicos dos grupos alimentados artificialmente, exceto para o per?odo de postura. Embora as f?meas alimentadas artificialmente por meio de tubos capilares n?o tenham atingido ingurgitamento total, os resultados apresentados demonstram que a t?cnica n?o apresentou efeito delet?rio sobre os aspectos biol?gicos da esp?cie.

In this work, we have analysed the temporal dynamics of gut-dwelling bacteria and Borrelia in the gut of the deer tick Ixodes ricinus. Using quantitative PCR, we have shown that levels of the tick intestinal microflora are profoundly decreased at later stages of feeding on whole blood but not on serum. Even though we noted that host complement system manages to interfere with Borrelia viability in vitro, we did not see any effect of host complement on Borrelia acquisition in adult ticks in vivo. However, we revealed that host hemoglobin is essential for Borrelia proliferation in the tick gut. All together, these data imply that, during feeding, levels of gut-dwelling bacteria and Borrelia are determined by the host. While hemoglobin seems to be detrimental for gut-dwelling bacteria, Borrelia require it in order to proliferate. During off-host stage, we showed that levels of gut-dwelling microflora are regulated by an intestinal transmembrane enzyme Dual oxidase. In conclusion, we aimed, and mostly succeeded, to perform pilot experiments describing the biology of a complex process of regulating gut microflora in the vector Ixodes ricinus and extend it by its impact on Borrelia acquisition

The intracellular proteolysis of ingested meal plays an essential role in tick development. The thesis focuses on the factors influencing the expressions and activities of digestive enzymes in Ixodes ricinus females during the feeding and post-feeding period. We have revealed the effect of fertilization on blood feeding and digestion. The females cannot reach the rapid engorgement phase without being fertilized. The rate of mated females in the nature proved the presumption that mating can occur even off the host. Implementation of in vitro feeding technique further extended our current knowledge about tick digestive apparatus. Adult females were fed on hemoglobin-rich and hemoglobin-poor diet and the mRNA expression levels of digestive proteases were determined. In line with obtained data, we assumed that albuminolysis is conducted by the same or similar pathway as hemoglobinolysis. The gene silencing method and protein immuno-detection were used to unequivocally identify the isoforms of 'early expressed' IrCL1 and 'late expressed' IrCL3 isoform of cathepsin L.