Soropositividade para Rickettsia spp. e Ehrlichia spp. em pacientes de Mato Grosso, Centro Oeste, Brasil

Abstract

Rickettsiosis and ehrlichiosis are emerging and re-emerging zoonosis, caused by obligate intracellular gram-negative bacteria with potential risk for public health. These diseases are characterized by common acute febrile symptoms and are associated with activities in sylvatic, rural environments and eventually peri-urban areas, which provide contact with vectors, ticks of the family Ixodidae. Antibodies and identification of some species of these bacteria in dogs, cats, horses and ticks in the state of Mato Grosso (MT) have been reported in the Pantanal, in Indian tribes and in the cities of Cuiabá and Várzea Grande. Despite of the presence of vectors and known reservoirs of these diseases throughout the state, the epidemiological situation of these illness is unknown in humans. The aim of this study was to perform a serological survey for Rickettsia spp. and Ehrlichia spp. in 506 human serum samples obtained in 19 cities of MT from patients with acute febrile illness suspected as dengue. To achieve that, the presence of IgG against Ehrlichia (E) canis, Rickettsia (R.) rickettsii, Rickettsia parkeri e Rickettsia amblyommii was tested by indirect immunofluorescence reaction (RIFI) and E. canis positive samples by immunosorbent assay (ELISA). From this total, 3,75% (19/506) were positive for IgG against at least one Rickettsia antigen, with titers between 64 and 1024. Positive patients are from Cuiabá (16), Várzea Grande (1), Poconé (1) and Pontes e Lacerda (1), cities in the close proximity to Pantanal, 11 are woman and eight man. One patient was <5 years-old, two patients belong to the 5-9 years age group, 10 to 20-39 years, five among the 40-59 years and one > 59 years, with a mean of 32 years. Most of the patients with IgG anti-Rickettsia reported to work with general services (3/19), mason (2/19), technical nursing (2/19), or student (2/19). For E. canis, 0,4% (2/506) were positive with titers 80 and 1280. These patients were from Cuiabá, one female, 43 years-old and a male, 24 years-old, both secretaries. Moreover, 20 of 21 patients are residents in urban areas, one noninformed and only two reported visits to risk area as well as six patients were dengue positive at the time of sample collection. The presence of antibodies in the sera of the tested patients provides serologic evidence of possible circulation of Rickettsia and Ehrlichia species in humans in the MT state.