Identification and isolation of rickettsiae from ticks of the Atlantic Rainforest

Abstract

Just recently a second tick-borne rickettsial disease was recognized in Brazil. The agent of this rickettsial disease, Rickettsia sp. strain Atlantic Rainforest, causes a milder disease than that determined by infection with Rickettsia rickettsii of Brazilian Spotted Fever. However, it is observed cross seroreactivity between the two rickettsiosis and the beginning of both infections as well as other diseases (dengue fever, leptospirosis meningococcemia, among others) are confused according to the clinical picture. A valuable information to consider the possibility of infection by these rickettsiae and anticipate the diagnosis is the knowledge of the geographical and ecological distribution of the agent and its vector. In Brazil, the tick Amblyomma ovale has been found harboring natural infections with Rickettsia sp. strain Atlantic Rainforest in several localities of the eastern coast of the country. The distribution of this tick includes other continental areas such as the Brazilian Savanah and Pampa biomes. However, knowledge about Rickettsia sp. strain Atlantic Rainforest infecting these inland populations is scarce. In this project we intend to search and isolate Rickettsia spp. from ticks collected further from the Atlantic coast in order to contribute with the knowledge about the distribution of these agents in Brazil, specifically the Rickettsia sp. strain Atlantic Rainforest. To this end, ticks will be collected from domestic dogs and from the environment in two areas of the Atlantic Rainforest biome: Serra do Japi, Jundiaí, São Paulo and Foz do Iguaçu, Paraná. It should be noted that preliminary data obtained from wild carnivores in Foz do Iguaçu, showed a high infestation prevalence with A. ovale.