In Brazil, Brazilian spotted fever was once considered the only tick-borne rickettsial disease. We report eschar-associated rickettsial disease that occurred after a tick bite. The etiologic agent is most related to Rickettsia parkeri, R. africae, and R. sibirica and probably widely distributed from São Paulo to Bahia in the Atlantic Forest.

Since the recognition of hantavirus as the agent responsible for haemorrhagic fever in Eurasia in the 1970s and, 20 years later, the descovery of hantavirus pulmonary syndrome in the Americas, the genus Hantavirus has been continually described throughout the World in a variety of wild animals. The diversity of wild animals infected with hantaviruses has only recently come into focus as a result of expanded wildlife studies. The known reservoirs are more than 80, belonging to 51 species of rodents, 7 bats (order Chiroptera) and 20 shrews and moles (order Soricomorpha). More than 80genetically related viruses have been classified within Hantavirus genus; 25 recognized as human pathogens responsible for a large spectrum of diseases in the Old and New World. In Brazil, where the diversity of mammals and especially rodents is considered one of the largest in the world, 9 hantavirus genotypes have been identified in 12 rodent species belonging to the genus Akodon, Calomys, Holochilus, Oligoryzomys, Oxymycterus, Necromys and Rattus. Considering the increasing number of animals that have been implicated as reservoirs of different hantaviruses, the understanding of this diversity is important for evaluating the risk of distinct hantavirus species as human pathogens.

Most human pathogenic hantaviruses cause severe hemorrhagic fevers with a high rate of fatalities, such as occurs due to the genotypes causing hantavirus cardiopulmonary syndrome carried by the New World Sigmodontinae and Neotominae rodents. An increasing number of outbreaks and the possibility of cases spreading over international borders have led to greater interest in these viruses and the environmental determinants that facilitate their transmission. Rodents, shrews, moles and bats act as reservoir hosts of hantaviruses, and within the hantavirus transmission flow, the prevalence and distribution of infection in reservoir hosts is influenced by a range of factors. Climate change and landscape alteration affect hantavirus transmission, but the outcomes can differ among different hantaviruses and for the same virus in differentbiomes. However, it is evident that the underlying mechanisms that mediate hantavirus transmission are largely unknown, so that much work remains to be done regarding the transmission dynamics of hantaviruses. Overall, our review highlights the importance of examining interactions over several trophic levels and the underlying mechanisms (density and trait-mediated indirect effects) linking predation risk and hantavirus transmission, to develop an ecological framework to understand disease in natural, preserved and degraded systems.