ROSELY DOS SANTOS MALAFRONTE
Projetos de Pesquisa
Unidades Organizacionais
SCPROTOZ-83, Instituto de Medicina Tropical
LIM/49 - Laboratório de Protozoologia, Hospital das Clínicas, Faculdade de Medicina - Líder
LIM/49 - Laboratório de Protozoologia, Hospital das Clínicas, Faculdade de Medicina - Líder
7 resultados
Resultados de Busca
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- Merozoite surface protein-1 genetic diversity in Plasmodium malariae and Plasmodium brasilianum from Brazil(2015) GUIMARAES, Lilian O.; WUNDERLICH, Gerhard; ALVES, Joao M. P.; BUENO, Marina G.; ROEHE, Fabio; CATAO-DIAS, Jose L.; NEVES, Amanda; MALAFRONTE, Rosely S.; CURADO, Izilda; DOMINGUES, Wilson; KIRCHGATTER, KarinBackground: The merozoite surface protein 1 (MSP1) gene encodes the major surface antigen of invasive forms of the Plasmodium erythrocytic stages and is considered a candidate vaccine antigen against malaria. Due to its polymorphisms, MSP1 is also useful for strain discrimination and consists of a good genetic marker. Sequence diversity in MSP1 has been analyzed in field isolates of three human parasites: P. falciparum, P. vivax, and P. ovale. However, the extent of variation in another human parasite, P. malariae, remains unknown. This parasite shows widespread, uneven distribution in tropical and subtropical regions throughout South America, Asia, and Africa. Interestingly, it is genetically indistinguishable from P. brasilianum, a parasite known to infect New World monkeys in Central and South America. Methods: Specific fragments (1 to 5) covering 60 % of the MSP1 gene (mainly the putatively polymorphic regions), were amplified by PCR in isolates of P. malariae and P. brasilianum from different geographic origin and hosts. Sequencing of the PCR-amplified products or cloned PCR fragments was performed and the sequences were used to construct a phylogenetic tree by the maximum likelihood method. Data were computed to give insights into the evolutionary and phylogenetic relationships of these parasites. Results: Except for fragment 4, sequences from all other fragments consisted of unpublished sequences. The most polymorphic gene region was fragment 2, and in samples where this region lacks polymorphism, all other regions are also identical. The low variability of the P. malariae msp1 sequences of these isolates and the identification of the same haplotype in those collected many years apart at different locations is compatible with a low transmission rate. We also found greater diversity among P. brasilianum isolates compared with P. malariae ones. Lastly, the sequences were segregated according to their geographic origins and hosts, showing a strong genetic and geographic structure. Conclusions: Our data show that there is a low level of sequence diversity and a possible absence of allelic dimorphism of MSP1 in these parasites as opposed to other Plasmodium species. P. brasilianum strains apparently show greater divergence in comparison to P. malariae, thus P. malariae could derive from P. brasilianum, as it has been proposed.
- Assessment of asymptomatic Plasmodium spp. infection by detection of parasite DNA in residents of an extra-Amazonian region of Brazil(2018) ALENCAR, Filomena E. C. de; MALAFRONTE, Rosely dos Santos; CERUTTI JUNIOR, Crispim; FERNANDES, Licia Natal; BUERY, Julyana Cerqueira; FUX, Blima; REZENDE, Helder Ricas; DUARTE, Ana Maria Ribeiro de Castro; MEDEIROS-SOUSA, Antonio Ralph; MIRANDA, Angelica EspinosaBackground: 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 in which asymptomatic carriers play an important role. Objectives: To determine the incidence of asymptomatic infection by detecting Plasmodium spp. DNA and its role in residual 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 Espirito 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. Followup 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 personyears or 1.25 infections per 100 person-years for each species. A mathematical transmission model was applied, using a low frequency of human carriers and the vector density in the region, and calculated based on previous studies in the same locality whose results were subjected to a linear regression. This analysis suggests that the transmission chain is unlikely to be based solely on human carriers, regardless of whether they are symptomatic or not. Conclusion: The low incidence of cases and the low frequency of asymptomatic malaria carriers investigated make it unlikely that the transmission chain in the region is based solely on human hosts, as cases are isolated one from another by hundreds of kilometers and frequently by long periods of time, reinforcing instead the hypothesis of zoonotic transmission.
- Mitochondrial genome of Plasmodium vivax/simium detected in an endemic region for malaria in the Atlantic Forest of Espirito Santo state, Brazil: do mosquitoes, simians and humans harbour the same parasite?(2017) BUERY, Julyana Cerqueira; RODRIGUES, Priscila Thihara; NATAL, Licia; SALLA, Lais Camoese; LOSS, Ana Carolina; VICENTE, Creuza Rachel; REZENDE, Helder Ricas; DUARTE, Ana Maria Ribeiro de Castro; FUX, Blima; MALAFRONTE, Rosely dos Santos; FALQUETO, Aloisio; CERUTTI JR., CrispimBackground: 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 Espirito 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 Espirito 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. After amplification, the mitochondrial genome was completely sequenced and compared with a haplotype network which included all sequences of P. vivax/simium mitochondrial genomes sampled from humans and simians from all regions in Brazil. Results: The haplotype network indicates that humans and simians from the Atlantic Forest become infected by the same haplotype, but some isolates from humans are not identical to the simian isolate. In addition, the plasmodial DNA extracted from mosquitoes revealed sequences different from those obtained from simians, but similar to two isolates from humans. Conclusions: These findings strengthen support for the hypothesis that in the Atlantic Forest, and especially in the state with the highest frequency of bromeliad-malaria in Brazil, parasites with similar molecular backgrounds are shared by humans and simians. The recognized identity between P. vivax and P. simium at the species level, the sharing of haplotypes, and the participation of the same vector in transmitting the infection to both host species indicate interspecies transference of the parasites. However, the intensity, frequency and direction of this transfer remain to be clarified.
- Unexpected detection of Plasmodium vivax and Plasmodium falciparum DNA in asymptomatic blood donors: fact or artifact?(2014) MENDRONE JR., Alfredo; CERUTTI JR., Crispim; LEVI, Jose Eduardo; BOULOS, Marcos; SANCHEZ, Maria Carmen Arroyo; MALAFRONTE, Rosely dos Santos; SANTI, Silvia Maria Di; ODONE JR., VicenteA study searching for Plasmodium vivax and Plasmodium falciparum DNA among blood donors from the non-endemic area in Brazil reported a rate of 7.41%. This number is at least three times higher than what has been observed in blood donors from the Amazon, an endemic area concentrating >99% of all malaria cases in Brazil. Moreover, the majority of the donors were supposedly infected by P. falciparum, a rare finding both in men and anophelines from the Atlantic forest. These findings shall be taken with caution since they disagree with several publications in the literature and possibly overestimate the actual risk of malaria transmission by blood transfusion in Sao Paulo city.
- Epidemiology of Disappearing Plasmodium vivax Malaria: A Case Study in Rural Amazonia(2014) BARBOSA, Susana; GOZZE, Amanda B.; LIMA, Nathalia F.; BATISTA, Camilla L.; BASTOS, Melissa da Silva; NICOLETE, Vanessa C.; FONTOURA, Pablo S.; GONCALVES, Raquel M.; VIANA, Susana Ariane S.; MENEZES, Maria Jose; SCOPEL, Kezia Katiani G.; CAVASINI, Carlos E.; MALAFRONTE, Rosely dos Santos; SILVA-NUNES, Monica da; VINETZ, Joseph M.; CASTRO, Marcia C.; FERREIRA, Marcelo U.Background: New frontier settlements across the Amazon Basin pose a major challenge for malaria elimination in Brazil. Here we describe the epidemiology of malaria during the early phases of occupation of farming settlements in Remansinho area, Brazilian Amazonia. We examine the relative contribution of low-density and asymptomatic parasitemias to the overall Plasmodium vivax burden over a period of declining transmission and discuss potential hurdles for malaria elimination in Remansinho and similar settings. Methods: Eight community-wide cross-sectional surveys, involving 584 subjects, were carried out in Remansinho over 3 years and complemented by active and passive surveillance of febrile illnesses between the surveys. We used quantitative PCR to detect low-density asexual parasitemias and gametocytemias missed by conventional microscopy. Mixed-effects multiple logistic regression models were used to characterize independent risk factors for P. vivax infection and disease. Principal Findings/Conclusions: P. vivax prevalence decreased from 23.8% (March-April 2010) to 3.0% (April-May 2013), with no P. falciparum infections diagnosed after March-April 2011. Although migrants from malaria-free areas were at increased risk of malaria, their odds of having P. vivax infection and disease decreased by 2-3% with each year of residence in Amazonia. Several findings indicate that low-density and asymptomatic P. vivax parasitemias may complicate residual malaria elimination in Remansinho: (a) the proportion of subpatent infections (i. e. missed by microscopy) increased from 43.8% to 73.1% as P. vivax transmission declined; (b) most (56.6%) P. vivax infections were asymptomatic and 32.8% of them were both subpatent and asymptomatic; (c) asymptomatic parasite carriers accounted for 54.4% of the total P. vivax biomass in the host population; (d) over 90% subpatent and asymptomatic P. vivax had PCR-detectable gametocytemias; and (e) few (17.0%) asymptomatic and subpatent P. vivax infections that were left untreated progressed to clinical disease over 6 weeks of follow-up and became detectable by routine malaria surveillance.
- Reassessment of asymptomatic carriers of Plasmodium spp. in an endemic area with a very low incidence of malaria in extra-Amazonian Brazil(2017) ALENCAR, Filomena E. C. de; MALAFRONTE, Rosely dos Santos; CERUTTI JR., Crispim; FERNANDES, Licia Natal; BUERY, Julyana Cerqueira; FUX, Blima; REZENDE, Helder Ricas; MIRANDA, Angelica EspinosaBackground: Regions with residual transmission are potential obstacles to the elimination of malaria. It is, therefore, essential to understand the factors associated with the maintenance of endemic malaria in these areas. The objective was to investigate whether the status of asymptomatic carriers of Plasmodium spp. DNA is maintained in the long term in an extra-Amazonian region of Brazil with low incidence, residual malaria transmission. Methods: Asymptomatic carriers of Plasmodium DNA detected in a survey carried out between 2001 and 2004 were reassessed between 2010 and 2011 using questionnaires, PCR and thick and thin blood smear tests three times at 3-month intervals. Results: Of the 48 carriers detected between 2001 and 2004, 37 were located. Of these, only two had positive PCR results and, as in the first survey, Plasmodium malariae DNA was detected. Conclusion: The findings suggest that untreated dwellers from this extra-Amazonian region, who initially harbour malaria parasites, may become negative without ever developing apparent symptoms of the disease. Although the possibility of re-infection cannot be ruled out, the finding of two individuals harbouring P. malariae, both in the first and in the second survey, may be compatible with a long-term carrier state for this parasite. Since most clinical cases of malaria in the region are a consequence of infection by Plasmodium vivax, the epidemiological impact of such long-term carriage would be limited.
- Vivax malaria in an Amazonian child with dilated cardiomyopathy(2014) MARTINS, Antonio C.; LINS, Jamille B.; SANTOS, Luana M. N.; FERNANDES, Licia N.; MALAFRONTE, Rosely S.; MAIA, Teresa C.; RIBERA, Melissa C. V.; RIBERA, Ricardo B.; SILVA-NUNES, Monica daA child living in the Brazilian Amazon region who had had vivax malaria at the age of 11 months was admitted three months later with a history of progressive dyspnoea and fever, which culminated in respiratory distress and severe dilated cardiomyopathy at hospital admission in a malaria-free area. She received treatment for cardiac insufficiency and was tested for malaria with two thick blood smears, which were negative. There was general improvement of cardiorespiratory function in the next two weeks, but in the third week of hospital admission, there was re-appearance of fever, severe anaemia, severe plaquetopaenia, and respiratory distress. A third thick blood smear was positive for Plasmodium vivax mono-infection, which was confirmed by molecular methods. A serological panel with the most prevalent infectious agents known to cause myocarditis was performed, and specific anti-cytomegalovirus (CMV) IgM and elevated levels of anti-CMV IgG were also detected in the serum. After treatment for malaria, there was improvement of respiratory distress, although cardiac function did not recover. She was discharged home with drugs for cardiac insufficiency and is currently under follow-up with a paediatric cardiologist as an outpatient. This report presents a young child with several episodes of vivax malaria who suffers from cardiac insufficiency, probably related to CMV-induced myocarditis.