[Ticks of genus Amblyomma (Acari: Ixodidae) and their relationship with hosts in endemic area for spotted fever in the State of São Paulo].

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.