Abstract
BackgroundTrypanosoma cruzi infection via oral route results in outbreaks or cases of acute Chagas disease (ACD) in different Brazilian regions and poses a novel epidemiological scenario. In the Espírito Santo state (southeastern Brazil), a fatal case of a patient with ACD led us to investigate the enzootic scenario to avoid the development of new cases. At the studied locality, Triatoma vitticeps exhibited high T. cruzi infection rates and frequently invaded residences.MethodsSylvatic and domestic mammals in the Rio da Prata locality, where the ACD case occurred, and in four surrounding areas (Baia Nova, Buenos Aires, Santa Rita and Todos os Santos) were examined and underwent parasitological and serological tests. Triatomines were collected for a fecal material exam, culturing and mini-exon gene molecular characterization, followed by RFLP-PCR of H3/Alul. Paraffin-embedded cardiac tissue of a patient was washed with xylene to remove paraffin and DNA was extracted using the phenol-chloroform method. For genotype characterization, PCR was performed to amplify the 1f8, GPI and 18S rRNA genes. In the case of V7V8 SSU rRNA, the PCR products were molecularly cloned. PCR products were sequenced and compared to sequences in GenBank. Phylogenetic analysis using maximum likelihood method with 1000 bootstrap replicates was performed.ResultsNone of the animals showed positive hemocultures. Three rodents and two dogs showed signs of infection, as inferred from borderline serological titers. T. vitticeps was the only triatomine species identified and showed T. cruzi infection by DTUs TcI and TcIV. The analysis of cardiac tissue DNA showed mixed infection by T. cruzi (DTUs I, II, III and IV) and Trypanosoma dionisii.ConclusionsEach case or outbreak of ACD should be analyzed as a particular epidemiological occurrence. The results indicated that mixed infections in humans may play a role in pathogenicity and may be more common than is currently recognized. Direct molecular characterization from biological samples is essential because this procedure avoids parasite selection. T. dionisii may under certain and unknown circumstances infect humans. The distribution of T. cruzi DTUS TcIII and TcIV in Brazilian biomes is broader than has been assumed to date.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1754-4) contains supplementary material, which is available to authorized users.
Highlights
Trypanosoma cruzi infection via oral route results in outbreaks or cases of acute Chagas disease (ACD) in different Brazilian regions and poses a novel epidemiological scenario
Trypanosoma cruzi marinkellei is transmitted by triatomine insects of the genus Cavernicola, and Trypanosoma dionisii is transmitted by Cimicidae
Identification of Trypanosoma cruzi Discrete Typing Units (DTUs) and T. dionisii in cardiac tissue In this study, we decided to use three nuclear markers to genotype the DNA obtained from the cardiac tissue: 1f8, glucose-phosphate isomerase (GPI) and 18S rRNA genes
Summary
Trypanosoma cruzi infection via oral route results in outbreaks or cases of acute Chagas disease (ACD) in different Brazilian regions and poses a novel epidemiological scenario. The genus Trypanosoma (Trypanosomatidae, Kinetoplastida), which includes the subgenus Schizotrypanum, is composed of numerous species that are distributed worldwide. With the exception of Trypanosoma cruzi, other species of this subgenus are restricted to bats. Due to their morphological similarity, these other species have been classically described as T. cruzi-like [1, 2]. The biological cycles of Schizotrypanum trypanosomes are similar, differing only in the identity of their mammalian hosts and their hemipteran vectors. Species of Schizotrypanum are the only trypanosomes described far that infect mammalian cells and multiply inside them as amastigotes [2,3,4]. Despite being the subject of intensive study for more than 100 years, there are still several unanswered questions pertaining to the biology of T. cruzi
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