RESUMO
The hypotheses put forward to explain the malaria transmission cycle in extra-Amazonian Brazil, an area of very low malaria incidence, are based on either a zoonotic scenario involving simian malaria, or a scenario inwhich asymptomatic carriers play an important role. Objectives: To determine the incidence of asymptomatic infection by detecting Plasmodium spp. DNA and its role inresidual malaria transmission in a non-Amazonian region of Brazil. Methods: Upon the report of the first malaria case in 2010 in the Atlantic Forest region of the state of Espírito Santo, inhabitants within a 2 km radius were invited to participate in a follow-up study. After providing signed informed consent forms, inhabitants filled out a questionnaire and gave blood samples for PCR, and thick and thin smears. Follow up visits were performed every 3 months over a 21 month period, when new samples were collected and information was updated. Results: Ninety-two individuals were initially included for follow-up. At the first collection, all of them were clearly asymptomatic. One individual was positive for Plasmodium vivax, one for Plasmodium malariae and one for both P.vivax and P. malariae, corresponding to a prevalence of 3.4% (2.3% for each species). During follow-up, four new PCR positive cases (two for each species) were recorded, corresponding to an incidence of 2.5 infections per 100 person years or 1.25 infections per 100 person-years for each species...
Assuntos
Humanos , Animais , Malária/diagnóstico , Malária/transmissão , Plasmodium malariae/crescimento & desenvolvimento , Plasmodium malariae/genética , Plasmodium vivax/crescimento & desenvolvimento , Plasmodium vivax/genética , Portador Sadio/diagnósticoRESUMO
The transmission of malaria in the extra-Amazonian regions of Brazil, although interrupted in the 1960s, has persisted to the present time in some areas of dense Atlantic Forest, with reports of cases characterized by particular transmission cycles and clinical presentations. Bromeliad-malaria, as it is named, is particularly frequent in the state of Espírito Santo, with Plasmodium vivax being the parasite commonly recognized as the aetiologic agent of human infections. With regard to the spatial and temporal distances between cases reported in this region, the transmission cycle does not fit the traditional malaria cycle. The existence of a zoonosis, with infected simians participating in the epidemiology, is therefore hypothesized. In the present study, transmission of bromeliad-malaria in Espírito Santo is investigated, based on the complete mitochondrial genome of DNA extracted from isolates of Plasmodium species, which had infected humans, a simian from the genus Allouata, and Anopheles mosquitoes. Plasmodium vivax/simium was identified in the samples by both nested PCR and real-time PCR...