Biology subjects

Lourenco-de-Oliveira, R.

Publications and source records attributed to Lourenco-de-Oliveira, R..

6 recordsLinked to original sources

bioRxiv2020

Oviposition in flight: the Sabethes albiprivus incredible egg throwing behavior

Mosquitoes display highly variable oviposition strategies and behavior. By using a high-speed camera, we detailly documented for the first time the egg-throwing strategy of the sylvatic yellow fever vector Sabethes albiprivus Theobald in laboratory. An oviposition trap made with sapucaia nut for field collection of tree-hole mosquitoes and obtaining Sa. albiprivus eggs either in the field or in the laboratory colony is described.

zoology↗

bioRxiv2019

A new high-throughput tool to screen mosquito-borne viruses in Zika virus endemic/epidemic areas

Mosquitoes are vectors of arboviruses affecting animal and human health. Arboviruses circulate primarily within an enzootic cycle and recurrent spillovers contribute to the emergence of human-adapted viruses able to initiate an urban cycle involving anthropophilic mosquitoes. The increasing volume of travel and trade offers multiple opportunities for arbovirus introduction in new regions. This scenario has been exemplified recently with the Zika pandemic. To incriminate a mosquito as vector of a pathogen, several criteria are required such as the detection of natural infections in mosquitoes. In this study, we used a high-throughput chip based on the BioMarkTM Dynamic arrays system capable of detecting 64 arboviruses in a single experiment. A total of 17,958 mosquitoes collected in Zika-endemic/epidemic countries (Brazil, French Guiana, Guadeloupe, Suriname, Senegal, and Cambodia) were analyzed. Here we show that this new tool can detect endemic and epidemic viruses in different mosquito species in an epidemic context. Thus, this fast and low-cost method can be suggested as a novel epidemiological surveillance tool to identify circulating arboviruses.

molecular biology↗

bioRxiv2019

Howler monkeys are the reservoir of malaria parasites causing zoonotic infections in the Atlantic forest of Rio de Janeiro

BackgroundAlthough malaria transmission was eradicated from southeast Brazil, a significant increase in the number of Plasmodium vivax-like autochthonous human cases has been reported in remote areas of the Atlantic Forest in the last decades in Rio de Janeiro (RJ) state, including an outbreak in 2015-2016. The singular clinical and epidemiological aspects of several human cases combined with molecular and genetic data revealed that they were due to the non-human primate (NHP) parasite P. simium. The full understanding of the epidemiology of the autochthonous malaria in southeastern Brazil depends, however, upon the knowledge on the circulation of NHP Plasmodium in the foci and the determination of its reservoirs.\n\nMethodologyA large sampling effort was carried out in the Atlantic forest of RJ and its bordering states (Minas Gerais, Sao Paulo, Espirito Santo) for capture and examination of free-living NHPs. Blood and/or viscera were analyzed for Plasmodia infections through molecular and microscopic techniques.\n\nPrincipal findingsIn total, 146 NHPs of six species, from 30 counties in four states were tested. Howler monkeys (A. guariba clamitans) were the only NHP species found infected. In RJ, 26% of howlers were positive, among them 17% were found to be infected with P. simium. Importantly, specific single nucleotide polymorphisms were detected in all P. simium infected howlers regardless geographical origin of malaria foci. Interestingly, 71% of P. simium infected NHP were from the coastal slope of a mountain chain (Serra do Mar), where most human cases have been occurring. P. brasilianum/malariae was detected for the first time in 14% free-living howlers in RJ as well as in 25% of those from the Espirito Santo state. Moreover, malarial pigment was detected in spleen fragments of 50% of a subsample composed of howler monkeys found dead in both RJ and ES. All NHPs were negative for P. falciparum.\n\nConclusions/SignificanceOur data indicate the howler monkeys as the main reservoir of the Atlantic forest human malaria in RJ and other sites in Southeast Brazil and reinforce its zoonotic nature.\n\nAuthor summaryThe present work consists of an unprecedented capture effort and large-scale field survey of plasmodial species in Non-human primates (NHPs) in RJ, a state recording a three-decade history of autochthonous human cases of benign tertian malaria pending epidemiological clarification of their origin. For the first time, we describe infection rates by Plasmodium sp.in free-living NHP, match the spatial distribution of P. simium in NHP with that of local human cases of benign tertian malaria due to this parasite, disclose howler monkeys as the only confirmed reservoir of this zoonotic malaria in the state and showed that specific single nucleotide polymorphisms were present in all P. simium infected howlers, regardless of the geographical origin of malaria foci. It is also the first time that P. brasilianum/malariae is recorded in free-living NHPs from Rio de Janeiro and the widespread distribution of this quartan-malaria parasite of zoonotic potential in the state is illustrated. Together, these findings increase the understanding about the simian malaria parasites in Atlantic Forests, as well as on the zoonotic character of autochthonous human malaria in Rio de Janeiro, providing subsidies for shaping surveillance and control.

ecology↗

bioRxiv2019

Distinct YFV lineages co-circulated in the Central-Western and Southeastern Brazilian regions from 2015 to 2018

The current outbreak of yellow fever virus (YFV) that is afflicting Brazil since the end of 2016 probably originated from a re-introduction of YFV from endemic areas into the non-endemic Southeastern Brazil. However, the lack of genomic sequences from endemic regions hinders the tracking of YFVs dissemination routes. We assessed the origin and spread of the ongoing YFV Brazilian outbreak analyzing a new set of YFV strains infecting humans, non-human primates (NHP) and mosquitoes sampled across five Brazilian states from endemic and non-endemic regions between 2015 and 2018. We found two YFV sub-clade 1E lineages circulating in NHP from Goias state (GO), resulting from independent viral introductions into the Araguaia tributary river basin: while the strain from 2017 clustered intermingled with Venezuelan YFV strains from 2000, the YFV strain sampled in 2015 clustered with sequences of the current YFV outbreak in the Brazilian Southeastern region (named YFV2015-2018 lineage), displaying the same molecular signature associated to the current YFV outbreak. After its introduction in GO at around mid-2014, the YFV2015-2018 lineage followed two paths of dissemination outside GO, originating two major YFV sub-lineages: 1) the YFVMG/ES/RJ sub-lineage spread sequentially from the eastern area of Minas Gerais state to Espirito Santo and then to Rio de Janeiro states, following the Southeast Atlantic basin; 2) the YFVMG/SP sub-lineage spread from the southwestern area of Minas Gerais to the metropolitan region of Sao Paulo state, following the Parana basin. These results indicate the ongoing YFV outbreak in Southeastern Brazil originated from a dissemination event from GO almost two years before its recognition at the end of 2016. From GO this lineage was introduced in Minas Gerais state at least two times, originating two sub-lineages that followed different routes towards densely populated areas. The spread of YFV outside endemic regions for at least four years stresses the imperative importance of the continuous monitoring of YFV to aid decision-making for effective control policies aiming the increase of vaccination coverage to avoid the YFV transmission in densely populated urban centers.

epidemiology↗

bioRxiv2017

Genomic and structural features of the Yellow Fever virus from the 2016-2017 Brazilian outbreak

Brazil has been suffering a severe sylvatic epidemic of yellow fever virus (YFV) since late 2016. Analysis of full-length YFV genomes from all hosts involved in the Brazilian 2017 outbreak reveals that they belong to sub-lineage 1E within modern-lineage, but display several unique amino acid substitutions in highly conserved positions at NS3 and NS5 viral proteins. Evolutionary analyses indicate that YFV carrying that set of amino acid substitution circulates in the Southern Brazilian region for several months before being detected in December 2016. Structural and selection analyses support that some of these substitutions were under positive selection and could impact enzyme structure and function. Altogether, this evidence demonstrated that the current Brazilian YFV carries unique amino acid signatures in the non-structural proteins and support the hypothesis that those substitutions may be affecting the viral fitness and transmissibility.

microbiology↗

bioRxiv2017

Plasmodium simium causing human malaria: a zoonosis with outbreak potential in the Rio de Janeiro Brazilian Atlantic forest

BackgroundMalaria was eliminated from Southern and Southeastern Brazil over 50 years ago. However, an increasing number of autochthonous episodes attributed to Plasmodium vivax have been recently reported in the Atlantic forest region of Rio de Janeiro State. As P. vivax-like non-human primate malaria parasite species Plasmodium simium is locally enzootic, we performed a molecular epidemiological investigation in order to determine whether zoonotic malaria transmission is occurring.\n\nMethodsBlood samples of humans presenting signs and/or symptoms suggestive of malaria as well as from local howler-monkeys were examined by microscopy and PCR. Additionally, a molecular assay based on sequencing of the parasite mitochondrial genome was developed to distinguish between P. vivax and P. simium, and applied to 33 cases from outbreaks occurred in 2015 and 2016.\n\nResultsOf 28 samples for which the assay was successfully performed, all were shown to be P. simium, indicating the zoonotic transmission of this species to humans in this region. Sequencing of the whole mitochondrial genome of three of these cases showed that P. simium is most closely related to P. vivax parasites from South American.\n\nFindingsThe explored malaria outbreaks were caused by P. simium, previously considered a monkey-specific malaria parasite, related to but distinct from P. vivax, and which has never conclusively been shown to infect humans before.\n\nInterpretationThis unequivocal demonstration of zoonotic transmission, 50 years after the only previous report of P. simium in man, leads to the possibility that this parasite has always infected humans in this region, but that it has been consistently misdiagnosed as P. vivax due to a lack of molecular typing techniques. Thorough screening of the local non-human primate and anophelines is required to evaluate the extent of this newly recognized zoonotic threat to public health and malaria eradication in Brazil.\n\nFundingFundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado de Rio de Janeiro (Faperj), The Brazilian National Council for Scientific and Technological Development (CNPq), JSPS Grant-in-Aid for scientific research, Secretary for Health Surveillance (SVS) of the Ministry of Health, Global Fund, and PRONEX Program of the CNPq.

genetics↗