Fabiana Cristina Pereira dos Santos

Features of Brazilian spotted fever in two different endemic areas in Brazil.

Brazilian spotted fever (BSF) caused by Rickettsia rickettsii is the most important rickettsiosis and the only reportable tick-borne disease in Brazil. In Brazil, the hard tick Amblyomma cajennense is the most important BSF vector; however, in São Paulo State, A. aureolatum was also recognized as a vector species in remaining Atlantic forest areas near the metropolitan area of São Paulo city. We analyzed clinical and epidemiological features of BSF cases from two distinct areas where A. cajennense (Area 1) and A. aureolatum (Area 2) are the incriminated vectors. The clinical features demonstrate the same severity pattern of BSF in both endemic areas. Differences in seasonality, patient characteristics (median age and gender), and epidemiological risk factors (animals host contact and vegetation characteristics) were observed and possibly could be attributed to the characteristics of each vector and their typical biological cycle (hosts and environment).

Phylogeography of Rickettsia rickettsii Genotypes Associated with Fatal Rocky Mountain Spotted Fever

Rocky Mountain spotted fever (RMSF), a tick-borne zoonosis caused by Rickettsia rickettsii, is among the deadliest of all infectious diseases. To identify the distribution of various genotypes of R. rickettsii associated with fatal RMSF, we applied molecular typing methods to samples of DNA extracted from formalin-fixed, paraffin-embedded tissue specimens obtained at autopsy from 103 case-patients from seven countries who died of RMSF. Complete sequences of one or more intergenic regions were amplified from tissues of 30 (29%) case-patients and revealed a distribution of genotypes consisting of four distinct clades, including the Hlp clade, regarded previously as a non-pathogenic strain of R. rickettsii. Distinct phylogeographic patterns were identified when composite case-patient and reference strain data were mapped to the state and country of origin. The phylogeography of R. rickettsii is likely determined by ecological and environmental factors that exist independently of the distribution of a particular tick vector.

Infective endocarditis due to Bartonella spp. and Coxiella burnetii: experience at a cardiology hospital in Sao Paulo, Brazil.

Abstract:  Bartonella spp. and Coxiella burnetii are recognized as causative agents of blood culture–negative endocarditis (BCNE) in humans and there are no studies of their occurrences in Brazil. The purpose of this study is to investigate Bartonella spp. and C. burnetii as a causative agent of culture‐negative endocarditis patients at a cardiology hospital in São Paulo, Brazil. From January 2004 to December 2004 patients with a diagnosis of endocarditis at our Institute were identified and recorded prospectively. They were considered to have possible or definite endocarditis according to the modified Duke criteria. Those with blood culture–negative were tested serologically using the indirect immunofluorescent assay (IFA) for Bartonella henselae, B. quintana, and C. burnetii. IFA‐IgG titers >800 for Bartonella spp. and C. burnetii were considered positive. A total of 61 patients with endocarditis diagnosis were evaluated, 17 (27%) were culture‐negative. Two have had IgG titer greater than 800 (≥3,200) against Bartonella spp. and one against C. burnetii (phase I and II≥6,400). Those with Bartonella‐induced endocarditis had a fatal disease. Necropsy showed calcifications and extensive destruction of the valve tissue, which is diffusely infiltrated with mononuclear inflammatory cells predominantly by foamy macrophages. The patient with C. burnetii endocarditis received specific antibiotic therapy. Reports of infective endocartitis due to Bartonella spp. and C. burnetii in Brazil reveal the importance of investigating the infectious agents in culture‐negative endocarditis.

Endocardite por Coxiella burnetii (febre Q): doença rara ou pouco diagnosticada? Relato de caso

Q fever is a zoonosis of worldwide distribution that is caused by Coxiella burnetii. However, reports of this disease in Brazil are rare. Seroepidemiological studies have shown relatively high frequencies of antibodies against Coxiella burnetii in populations with occupational exposure. In humans, it can be manifested clinically as acute or chronic disease. Endocarditis is the most frequent chronic form of Q fever and the form with the greatest morbidity and mortality. We report a severe case of endocarditis due to Coxiella burnetii acquired in Brazil that had a fatal outcome, despite specific antibiotic therapy and valve surgery treatment.

Genetic Identification of Rickettsial Isolates from Fatal Cases of Brazilian Spotted Fever and Comparison with Rickettsia rickettsii Isolates from the American Continents

ABSTRACT Fifteen bacterial isolates from spotted fever group rickettsiosis in Brazil were genetically identified as Rickettsia rickettsii. In a phylogenetic analysis with other R. rickettsii isolates from GenBank, the Central/South American isolates showed low polymorphism and formed a clade distinct from two North American clades, with the North American clades having greater in-branch polymorphism.

Rickettsia sp. Strain Atlantic Rainforest Infection in a Patient from a Spotted Fever-Endemic Area in Southern Brazil.

Santa Catarina State in southern Brazil is the state with the second highest number of laboratory-confirmed cases of spotted fever illness in Brazil. However, all these cases were confirmed solely by serological analysis (seroconversion to spotted fever group rickettsiae), which has not allowed identification of the rickettsial agent. Here, a clinical case of spotted fever illness from Santa Catarina is shown by seroconversion and molecular analysis to be caused by Rickettsia sp. strain Atlantic rainforest. This is the third confirmed clinical case due to this emerging rickettsial agent in Brazil. Like the previous two cases, the patient presented an inoculation eschar at the tick bite site. Our molecular diagnosis was performed on DNA extracted from the crust removed from the eschar. These results are supported by previous epidemiological studies in Santa Catarina, which showed that nearly 10% of the most common human-biting ticks were infected by Rickettsia sp. strain Atlantic rainforest.

A fatal case of Brazilian spotted fever in a non-endemic area in Brazil: the importance of having health professionals who understand the disease and its areas of transmission

Brazilian spotted fever (BSF) is caused by the bacterium Rickettsia rickettsii. Because of its high case-fatality rate and apparent increase in areas of transmission, it is considered to be the rickettsial illness of primary public health interest. Cases of this disease have historically occurred in Southeastern Brazil. This article reports the first fatal case of BSF in Southern Brazil. This case high lights the importance of BSF to be considered as a differential diagnosis for acute hemorrhagic fever in areas where cases of BSF may not be expected.

Resurgence of measles virus in São Paulo, Brazil.

The epidemic that occurred in SP in 1997 showed the circulation of the D6 group. After this period there was a decrease in the individuals susceptible to it. Due to good strategies for the close observation of measles virus, the circulation of indigenous cases was not registered for the mentioned period. However, in 2001, 2002 and 2005, cases of an imported virus belonging to the group D5 was registered.

Discovery of a new antiviral protein isolated Lonomia obliqua analysed by bioinformatics and real-time approaches.

This study presents a new recombinant protein that acts as a powerful antiviral (rAVLO—recombinant Antiviral protein of Lonomia obliqua). It was able to reduce the replication by 106 fold for herpes virus and by 104 fold for rubella virus. RT-PCR of viral RNA rAVLO treated infected cells also showed similar rate of inhibition in replication. The analysis of this protein by bioinformatics suggests that this protein is globular, secreted with a signal peptide and has the ability to bind to MHC class I. It was found that there are several protein binding sites with various HLA and a prevalence of α-helices in the N-terminal region (overall classified as a α/β protein type). BLAST similarity sequence search for corresponding cDNA did not reveal a similar sequence in Genbank, suggesting that it is from a novel protein family. In this study we have observed that this recombinant protein and hemolymph has a potent antiviral action. This protein was produced in a baculovirus/Sf-9 system. Therefore, these analyses suggest that this novel polypeptide is a candidate as a broad spectrum antiviral.

Brazilian spotted fever: Real-time PCR for diagnosis of fatal cases

Suspicion of Brazilian spotted fever (BSF) should occur in endemic regions upon surveillance of the acute febrile icteric hemorrhagic syndrome (AFIHS). However, limitations associated with currently available laboratory tests pose a challenge to early diagnosis, especially in fatal cases. Two real-time PCR (qPCR) protocols were evaluated to diagnose BSF in 110 fatal AFIHS cases, collected in BSF-endemic regions in 2009-2010. Of these, 24 were positive and 86 negative by indirect immunofluorescence (IFA) assay (cut-off IgG and/or IgM ≥ 128). DNA from these samples was used in the qPCR protocols: one to detect Rickettsia spp. (citrate synthase gene) and another to determine spotted fever group (SFG) Rickettsia species (OmpA gene). Of the 24 IFA-positive samples, 5 (21%) were positive for OmpA and 9 (38%) for citrate synthase. In the IFA-negative group (n=86), OmpA and citrate synthase were positive in 23 (27%) and 27 (31%), respectively. These results showed that the 2 qPCR protocols were about twice as sensitive as the IFA test alone (93% concordance). In conclusion, qPCR is a sensitive method for the diagnosis of fatal BSF cases and should be considered for routine surveillance of AFIHS in places like Brazil, where spotted fever-related lethality is high and other endemic diseases like dengue and leptospirosis can mislead diagnosis.