RESUMOForam avaliadas 7 espécies da mastofauna e 36 da avifauna quanto à prevalência e intensidade de infestação por carrapatos na ESALQ/USP, no Município de Piracicaba, SP. Analisaram-se 52 indivíduos da mastofauna e 158 da avifauna, parasitados por 12418 carrapatos. Os exemplares adultos (N= 7343) foram encontrados em parasitismo nas capivaras enquanto que os imaturos foram, na maioria, coletados de pequenos mamíferos e aves. Os principais hospedeiros para as formas imaturas, em ordem decrescente, foram gambás (69,1%), capivaras (24,4%) e urubus (3,7% Seven species of mammals and 36 of birds were investigated to determine the tick prevalence and intensity of infestation. The study was conducted at the Esalq/USP in Piracicaba municipality, State of São Paulo. It was collected 52 mammals and 158 birds parasitized by 12,418 ticks. Adult ticks (N= 7,343) were found on capybaras, while the immature were mainly collected on small mammals and birds. The main hosts for immatures in descending order were opossums (69.1%), capybara (24.4%) and black vultures (3.7%). Among the avifauna, the black vulture (Cathartidae) had the heaviest infestation (69.9%) followed by species of the Thamnophilidae and Turdidae families. Adult ticks collected on capybaras were A. cajennense (80.8%) and A. dubitatum (19.2%). Both tick species were also found on opossums corresponding to 72.4% and 27.6%, respectively. Due to easy capture and attractiveness for ticks, opossums could be used as bioindicators in Brazilian zoonotic areas with spotted fever. Considering the prevalence and also abundance of ticks, host attractiveness, proliferation and susceptibly for R. rickettsi infection, capybaras and opossums are the main amplifying hosts for this microorganism at the ESALQ/Campus, while horses, black vultures and stray cats act as secondary hosts.

The biological cycle of female ticks of Amblyomma cooperi was studied under controlled conditions. The study has begun with two engorged females collected in a naturally infested wild capybara. The larvae originated from the oviposition of these two females were used for collecting young adults through artificial infestations in rabbits. The female parasitic and free living phases were evaluated using artificial infestation of ticks in a capybara. The average body weight of females was 958.2± 175.6mg, the average pre-egg laying period was 8.5± 1.4 days, the reproductive efficiency index was 59.5± 4.2 and the nutritional efficiency index was 77.3± 4.8. The incubation and eclosion periods were 41.9 and 5.9 days, respectively, and the rate of eclosion was 64%. These figures were obtained under high relative humidity conditions which were necessary for the success of the egg incubation process of this species. The preliminary data obtained with the artificial infestation in rabbits raises the possibility of this and other domestic species be used as an epidemiologic link between the domestic and the wild environment with the potential exposure of human populations to A. cooperi and to the maculosa fever agent.