More about human monocytotropic ehrlichiosis in Brazil: serological evidence of nine new cases

Human Ehrlichia chaffeensis infections have been reported in North America, Asia and Europe, but only recently have human cases been reported in Brazil. Nine new human cases of E. chaffeensis infection diagnosed on a clinical and serological basis are reported. Serological tests were performed with indoor slides prepared with CDC stock DH-82 cells infected with E. chaffeensis (Arkansas strain). All but two patients were adults. Seven patients were male and two female. The fever duration varied from 4 to 120 days with a median of 6 days. All patients recalled previous tick attack. IgM was detected in four cases. Influenza like syndrome was the most frequent clinical form affecting five patients. Two patients had fever of unknown origin (FUO), one patient had blood culture-negative endocarditis and one had encephalitis. All patients except one recovered. Two patients were correctly treated. One patient with FUO had AIDS and unexplained pancytopenia. The occurrence of human ehrlichiosis by E. chaffeensis remains to be proved in Brazil; the cases reported here highlight the possibility of such disease occurrence in Brazil.

Antibodies to Rickettsia rickettsii, Rickettsia typhi, Coxiella burnetii, Bartonella henselae, Bartonella quintana, and Ehrlichia chaffeensis among healthy population in Minas Gerais, Brazil

Rickettsial diseases except those belonging to spotted fever group rickettsioses are poorly studied in South America particularly in Brazil where few epidemiological reports have been published. We describe a serosurvey for Rickettsia rickettsii, R. typhi, Coxiella burnetii, Bartonella henselae, B. quintana, and Ehrlichia chaffeensis in 437 healthy people from a Brazilian rural community. The serum samples were tested by indirected micro-immunoflourescence technique and a cutoff titer of 1:64 was used. The seroprevalence rates for R. rickettsii, R. typhi, C. burnetii, B. henselae, B. quintana, and E. chaffeensis were respectively 1.6 percent (7 samples); 1.1 percent (5 samples); 3.9 percent (17 samples); 13.7 percent (60 samples); 12.8 percent (56 samples), and 10.5 percent (46 samples). Frequent multiple/cross-reactivity was observed in this study. Age over 40 years old, urban profession, and rural residence were significantly associated with some but not all infections rate. Low seropositivity rates for R. rickettsii, R. typhi, and C. burnetii contrasted with higher rates of seropositivity for B. quintana, B. henselae, and E. chaffeensis. These results show that all tested rickettsial species or antigenically closely related possible exist in this particular region.