Biology subjects

Rezende, H. R.

Publications and source records attributed to Rezende, H. R..

4 recordsLinked to original sources

bioRxiv2025

Anopheles (Kerteszia) cruzii, the main malaria vector in the Brazilian Atlantic Forest, is a complex of at least five cryptic species

Malaria, a tropical disease caused by Plasmodium and transmitted by Anopheles, remains a public health concern in Brazil. While most cases occur in the Amazon, transmission persists in the Atlantic Forest, where Anopheles mosquitoes of the Kerteszia subgenus are the primary vectors of human and simian malaria. Previous studies using cytogenetics, isoenzymes, and molecular markers have suggested cryptic species within Anopheles (Kerteszia) cruzii and Anopheles (Kerteszia) bellator. We sequenced 55 genomes: 35 An. cruzii s.l. (four with Nanopore and 31 with Illumina), 12 An. bellator s.l., and eight An. homunculus, the latter two with Illumina. Phylogenomic analysis revealed at least five cryptic species within An. cruzii s.l., labelled A-E, with evidence of sympatry in some locations. Anopheles bellator s.l. also forms a species complex, comprising at least three distinct lineages. These cryptic species showed high genetic differentiation (FST range: 0.4-0.7), typical of interspecific comparisons. In contrast, An. homunculus populations showed low differentiation (FST [~] 0.2), suggesting a single widespread species. Our analysis confirms cryptic speciation in An. cruzii and An. bellator, but not in An. homunculus. These findings are important for understanding malaria transmission in the Atlantic Forest, given that vector competence may differ among cryptic species.

evolutionary biology↗

bioRxiv2020

Detection of Plasmodium vivax in a liver sample of a howler-monkey: one evidence more in favour of the identity between Plasmodium simium and P. vivax

IntroductionThe residual malaria of Atlantic Forest systems in Brazil occurs as an endemic disease with low frequency of cases. The chronological and spatial distance among the cases indicate an absence of fitness to the classical malaria cycle. This peculiar condition raised the suspicion of a reservoir, possibly the non-human primates. Simian and human malaria occur at the same places in that region, and there is already evidence of molecular identity between the simian parasites, Plasmodium simium and Plasmodium brasilianum, and the human parasites, Plasmodium vivax and Plasmodium malariae, respectively. Two different SNPs identified in the COX1 region of the Plasmodium vivax/simium of the Atlantic Forest reinforced its characterization as a zoonotic parasite. This finding supported the development of a PCR-RFLP protocol to identify such polymorphisms, and to monitor zoonotic malaria transmission. MethodsIn the present work, we tested the above-mentioned PCR-RFLP protocol in unprecedented mosquitoes and simian samples collected in Espirito Santo State, Brazil (ES). ResultsThe parasite found in the simian sample was P. vivax, contrary to what the protocol should indicate. In the mosquito samples, the protocol disclosed both forms of the parasite. ConclusionThis result suggests that the previously published pair of SNPs, and, consequently, the PCR-RFLP protocol, are not able to distinguish the dynamics of Plasmodium spp. circulation in the Atlantic Forest endemic area of ES.

molecular biology↗

bioRxiv2017

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 harbor the same parasite?

BackgroundThe 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 etiologic 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, zoonotic 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 in a haplotype network, including all sequences of P. vivax/simium mitochondrial genomes sampled from humans and simians from all regions in Brazil.\n\nResultsThe haplotype network demonstrates that humans and simians from the Atlantic Forest share 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.\n\nConclusionsThese findings reinforce the hypothesis that in the Atlantic Forest, and especially in the state with the highest frequency of bromeliad-malaria in Brazil, the same parasite species is shared by humans and simians, at least in part. The difference between the sequences of mosquitoes and simians raises two hypotheses: (1) two distinct transmission cycles for human malaria exist in the study area, one of them involving simians and the other exclusive to human hosts, or (2) there is only one transmission cycle involving humans and simians, but the identification of variations among simians was not possible due to a lack of other samples.

epidemiology↗

bioRxiv2017

Ecological characterization and infection of Anophelines (Diptera: Culicidae) of the Atlantic Forest in the southeast of Brazil over a 10 year period: Has the behaviour of the autochthonous malaria vector changed?

In the south and southeast of Brazil, autochthonous malaria cases can be found near Atlantic Forest fragments. The transmission is not totally clarified; thus, the behaviour of the possible vectors in those regions must be observed. An entomological and natural infection study was performed on anophelines (Diptera: Culicidae) captured in the municipalities of the mountainous region of Espirito Santo state in 2004-2005. Similarly, between the years 2014 and 2015, 12 monthly collections were performed at the permanent trapping station of the study mentioned above (Valsugana Velha, Santa Teresa, ES). Light traps with CO2 (CO2-baited Center for Disease Control [CDC] traps) were set in open areas, at the edge of the forest (canopy and ground) and inside the forest (canopy and ground), whereas Shannon traps were set on the edge of the forest. A total of 1,414 anophelines were collected from 13 species. Anopheles (Kerteszia) cruzii Dyar and Knab remained the most captured species in the CO2-baited CDC traps set in the forest canopy and was also the vector with the highest prevalence of Plasmodium vivax infection according to molecular PCR techniques. Regarding mosquitoes of the subgenus Nyssorhynchus, P. vivax was found only in abdomens, weakening the hypothesis that this subgenus also plays a role in malaria transmission in this specific region.\n\nSponsorshipEspirito Santo Research Foundation (Fundacao de Amparo a Pesquisa e Inovacao do Espirito Santo - FAPES).

epidemiology↗