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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% (7 samples); 1.1% (5 samples); 3.9% (17 samples); 13.7% (60 samples); 12.8% (56 samples), and 10.5% (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.

Dengue fever has been a major problem in hospital settings in Brazil for the past 15 years. The main concern has been the severe forms, i.e., dengue hemorrhagic fever and dengue shock syndrome. Hemorrhagic events of different degrees have also been a major concern. We report five cases of large vein thrombotic events associated with the acute phase of dengue fever, including a previously non-reported case of mesenteric vein thrombosis. Complications such as these could have been overlooked in the diagnosis of dengue fever, given that the major concern is the hemorrhagic event.

Tatumella ptyseos is the type species of the Tatumella genus (Enterobacteriaceae). This fermentative Gram-negative rod has only rarely been reported as a cause of human infections; there is very little information about it in the medical literature. We report here the first two Brazilian cases of T. ptyseos infections, both evolving to severe sepsis.

The effect of antibodies alone or complexed to antigen on an IgE response was compared in mice immunized with a low dose of antigen. The results demonstrated that immune complexes (ICs) at equivalence were more efficient than antibodies in promoting a suppression of this response when they were injected simultaneously or before, but not after, the antigen. This effect was dose dependent, antigen specific, and long lasting. Furthermore, only isologous ICs were suppressive. ICs prepared with IgG1 antibodies were more effective than ICs prepared with IgG2. Digestion of the Fc fragment of the antibody eliminated completely the suppressive action of antibodies alone, but not of ICs. These results indicate that, whereas an Fc-dependent mechanism is responsible for the effect of antibodies, an additional mechanism is also operating in suppression induced by ICs.

Q fever has been considered non-existing in Brazil where reports of clinical cases still cannot be found. This case-series of 16 patients is a result of a systematic search for such illness by means of clinical and serologic criteria. Serologic testing was performed by the indirect microimmunofluorescence technique using phase I/II C. burnetii antigens. Influenza-like syndrome was the most frequent clinical form (eight cases - 50%), followed by pneumonia, FUO (fever of unknown origin), mono-like syndrome (two cases - 12.5% each), lymphadenitis (one case - 6.3%) and spondylodiscitis associated with osteomyelitis (one case - 6.3%). The ages varied from four to 67 years old with a median of 43.5. All but one patient had positive serologic tests for phase II IgG whether or not associated with IgM positivity compatible with acute infection. One patient had both phase I and phase II IgG antibodies compatible with chronic Q fever. Seroconvertion was detected in 10 patients. Despite the known limitations of serologic diagnosis, the cases here reported should encourage Brazilian doctors to include Q fever as an indigenous cause of febrile illness. A febre Q continua sendo considerada inexistente no Brasil onde publicações de casos clínicos ainda não são encontráveis. Esta série de casos de 16 pacientes é resultado de uma busca sistemática para esta doença usando-se critérios clínicos e sorológicos. Os testes sorológicos foram realizados pela técnica de microimunofluorescência indireta utilizando-se antígenos de C. burnetii fase I e fase II. Síndrome influenza símile foi a forma clínica mais frequente (oito casos - 50%), seguida pela pneumonia, FOI (febre de origem indeterminada), síndrome mononucleose símile (dois casos - 12,5% cada) e por fim linfoadenite (um caso - 6,3%) e espondilodiscite associada à osteomielite (um caso - 6,3%). As idades variaram de quatro a 67 anos com mediana de 43,5. Todos os pacientes, com exceção de um, tinham testes sorológicos positivos para IgG anti fase II, associado ou não a IgM anti fase II, compatíveis com infecção aguda. Um paciente tinha tanto anticorpos IgG anti fase I quanto anti fase II compatíveis com febre Q crônica. Soroconversão foi detectada em 10 pacientes. A despeito das conhecidas limitações do diagnóstico sorológico os casos aqui relatados devem encorajar os médicos brasileiros a incluir a febre Q como causa nativa de doença febril neste país a ser pesquisada.

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.

Brazilian spotted fever, caused by Rickettsia rickettsii, has been increasingly reported in Brazil especially in the southeastern states. The severe and fulminant forms of the disease are not unusual but most of the reported fatal cases have shown some typical clinical clue, which leads the attending physician to a correct diagnosis. We report a probable case of atypical fulminant Brazilian spotted fever that presented full-blown septic shock associated with Adult Respiratory Distress Syndrome (ARDS) and delayed uncharacteristic rash with an over four-fold increase in reciprocal IgM, but not IgG titer against Rickettsia rickettsii. Brazilian practitioners should be aware of the possibility of Brazilian spotted fever as a cause of fulminant primary sepsis with ARDS; improved laboratory methods are necessary for the rapid diagnosis of such cases.

The authors report one case of Parinaud's oculoglandular syndrome associated with Paracoccidioides brasiliensis infection. No other medical report of this condition was found in the medical literature available at Index Medicus and Medline. The eye involvement has been rather uncommon in paracoccidioidomycosis and this report emphasizes the possibility of this kind of presentation making it also necessary to include paracoccidioidomycosis among the several known causes of Parinaud's oculoglandular syndrome. Os autores relatam um caso de síndrome oculoglandular de Parinaud associada à infecção por Paracoccidioides brasiliensis. Nenhum outro relato desta condição foi encontrado na literatura médica disponível pelo Index Medicus e Medline. O envolvimento ocular é incomum na paracoccidioidomicose e este relato enfatiza a possibilidade deste tipo de apresentação, tornando-se necessário incluir a paracoccidioidomicose entre as várias causas conhecidas de síndrome oculoglandular de Parinaud.

Reye's syndrome is an infrequently diagnosed medical condition affecting mainly children. The etiology, epidemiology and natural history of Reye's syndrome have been cloudily written in footnotes of medical books and exotic papers since the initial description in early 1950s. We report here a case of adult Reye's syndrome associated with serologic evidence of parvovirus B19 infection. Keywords: Reye's syndrome, parvovirus B19, human adult