Dissecting the phyloepidemiology of Trypanosoma cruzi I (TcI) in Brazil by the use of high resolution genetic markers.

BACKGROUND: Trypanosoma cruzi, the causal agent of Chagas disease, is monophyletic but genetically heterogeneous. It is currently represented by six genetic lineages (Discrete Typing Units, DTUs) designated TcI-TcVI. TcI is the most geographically widespread and genetically heterogeneous lineage, this as is evidenced by a wide range of genetic markers applied to isolates spanning a vast geographic range in Latin America. METHODOLOGY/PRINCIPAL FINDINGS: In total, 78 TcI isolated from hosts and vectors distributed in 5 different biomes of Brazil, were analyzed using 6 nuclear housekeeping genes, 25 microsatellite loci and one mitochondrial marker. Nuclear markers reveal substantial genetic diversity, significant gene flow between biomes, incongruence in phylogenies, and haplotypic analysis indicative of intra-DTU genetic exchange. Phylogenetic reconstructions based on mitochondrial and nuclear loci were incongruent, and consistent with introgression. Structure analysis of microsatellite data reveals that, amongst biomes, the Amazon is the most genetically diverse and experiences the lowest level of gene flow. Investigation of population structure based on the host species/genus, indicated that Didelphis marsupialis might play a role as the main disperser of TcI. CONCLUSIONS/SIGNIFICANCE: The present work considers a large TcI sample from different hosts and vectors spanning multiple ecologically diverse biomes in Brazil. Importantly, we combine fast and slow evolving markers to contribute to the epizootiological understanding of TcI in five distinct Brazilian biomes. This constitutes the first instance in which MLST analysis was combined with the use of MLMT and maxicircle markers to evaluate the genetic diversity of TcI isolates in Brazil. Our results demonstrate the existence of substantial genetic diversity and the occurrence of introgression events. We provide evidence of genetic exchange in TcI isolates from Brazil and of the relative isolation of TcI in the Amazon biome. We observe the absence of strict associations with TcI genotypes to geographic areas and/or host species

Limited risk of Zika virus transmission by five Aedes albopictus populations from Spain

Background: Aedes albopictus, the Asian tiger mosquito, is an exotic invasive species in Europe. It has substantial public health relevance due to its potential role in transmitting several human pathogens. Out of the European coun‑ tries, Spain has one of the highest risk levels of autochthonous arbovirus transmission due to both the high density of Ae. albopictus and the extensive tourist infux from vector-endemic areas. This study aims to investigate the suscep‑ tibility of fve Ae. albopictus populations from mainland Spain and the Balearic Islands to a Brazilian Zika virus (ZIKV) strain. Methods: The F1 generation of each Ae. albopictus population was orally challenged with a ZIKV-infected blood meal (1.8×106 PFU/ml). At 7 and 14 days post-infection (dpi), mosquito bodies (thorax and abdomen) and heads were individually analysed through RT-qPCR to determine the infection rate (IR) and dissemination rate (DR), respectively. The saliva of infected mosquitoes was inoculated in Vero cells and the transmission rate was assessed by plaque assay or RT-qPCR on ~33 individuals per population. Results: The IR and DR ranged between 12–88%, and 0–60%, respectively, suggesting that ZIKV is capable of cross‑ ing the midgut barrier. Remarkably, no infectious viral particle was found in saliva samples, indicating a low ability of ZIKV to overcome the salivary gland barrier. A subsequent assay revealed that a second non-infective blood meal 48 h after ZIKV exposure did not infuence Ae. albopictus vector competence. Conclusions: The oral experimental ZIKV infections performed here indicate that Ae. albopictus from Spain become infected and disseminate the virus through the body but has a limited ability to transmit the Brazilian ZIKV strain through biting. Therefore, the results suggest a limited risk of autochthonous ZIKV transmission in Spain by Ae. albopictusinfo:eu-repo/semantics/publishedVersio

Under pressure: phenotypic divergence and convergence associated with microhabitat adaptations in Triatominae.

BACKGROUND: Triatomine bugs, the vectors of Chagas disease, associate with vertebrate hosts in highly diverse ecotopes. It has been proposed that occupation of new microhabitats may trigger selection for distinct phenotypic variants in these blood-sucking bugs. Although understanding phenotypic variation is key to the study of adaptive evolution and central to phenotype-based taxonomy, the drivers of phenotypic change and diversity in triatomines remain poorly understood. METHODS/RESULTS: We combined a detailed phenotypic appraisal (including morphology and morphometrics) with mitochondrial cytb and nuclear ITS2 DNA sequence analyses to study Rhodnius ecuadoriensis populations from across the species' range. We found three major, naked-eye phenotypic variants. Southern-Andean bugs primarily from vertebrate-nest microhabitats (Ecuador/Peru) are typical, light-colored, small bugs with short heads/wings. Northern-Andean bugs from wet-forest palms (Ecuador) are dark, large bugs with long heads/wings. Finally, northern-lowland bugs primarily from dry-forest palms (Ecuador) are light-colored and medium-sized. Wing and (size-free) head shapes are similar across Ecuadorian populations, regardless of habitat or phenotype, but distinct in Peruvian bugs. Bayesian phylogenetic and multispecies-coalescent DNA sequence analyses strongly suggest that Ecuadorian and Peruvian populations are two independently evolving lineages, with little within-lineage phylogeographic structuring or differentiation. CONCLUSIONS: We report sharp naked-eye phenotypic divergence of genetically similar Ecuadorian R. ecuadoriensis (nest-dwelling southern-Andean vs palm-dwelling northern bugs; and palm-dwelling Andean vs lowland), and sharp naked-eye phenotypic similarity of typical, yet genetically distinct, southern-Andean bugs primarily from vertebrate-nest (but not palm) microhabitats. This remarkable phenotypic diversity within a single nominal species likely stems from microhabitat adaptations possibly involving predator-driven selection (yielding substrate-matching camouflage coloration) and a shift from palm-crown to vertebrate-nest microhabitats (yielding smaller bodies and shorter and stouter heads). These findings shed new light on the origins of phenotypic diversity in triatomines, warn against excess reliance on phenotype-based triatomine-bug taxonomy, and confirm the Triatominae as an informative model system for the study of phenotypic change under ecological pressure

Correction to: Under pressure: phenotypic divergence and convergence associated with microhabitat adaptations in Triatominae.

An amendment to this paper has been published and can be accessed via the original article

Rhodnius prolixus and R. robustus (Hemiptera: Reduviidae) nymphs show different locomotor patterns on an automated recording system

Submitted by Sandra Infurna ([email protected]) on 2017-03-21T12:31:37Z No. of bitstreams: 1 marcio_pavan_etal_IOC_2016.pdf: 1601311 bytes, checksum: bb66515f65545642f8ae077ceb5f61b5 (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2017-03-21T12:44:10Z (GMT) No. of bitstreams: 1 marcio_pavan_etal_IOC_2016.pdf: 1601311 bytes, checksum: bb66515f65545642f8ae077ceb5f61b5 (MD5)Made available in DSpace on 2017-03-21T12:44:10Z (GMT). No. of bitstreams: 1 marcio_pavan_etal_IOC_2016.pdf: 1601311 bytes, checksum: bb66515f65545642f8ae077ceb5f61b5 (MD5) Previous issue date: 2016Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Epidemiologia e Sistemática Molecular. Rio de Janeiro, RJ. Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biologia Molecular de Insetos. Rio de Janeiro, RJ. BrasilFundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Epidemiologia e Sistemática Molecular. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biologia Molecular de Insetos. Rio de Janeiro, RJ. Brasil / Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular (INCT-EM)/ CNPq, Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Epidemiologia e Sistemática Molecular. Rio de Janeiro, RJ. Brasil / Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular (INCT-EM)/ CNPq, Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biologia Molecular de Insetos. Rio de Janeiro, RJ. Brasil / Fundação Oswaldo cruz. Instituto Oswaldo Cruz. Laboratório de Bioquímica e Fisiologia de Insetos. Rio de Janeiro, RJ, Brasil.Circadian rhythms of triatomines, vectors of the etiological agent Trypanosoma cruzi responsible for Chagas disease, have been extensively studied in adults of the two most epidemiologically relevant vector species, Rhodnius prolixus and Triatoma infestans. However, little attention has been dedicated to the activity patterns in earlier developmental stages, even though triatomine nymphs are equally capable of transmitting T. cruzi to humans. Because circadian rhythms may differ even between closely related species, studies that focus on this behavioral trait can also be used to shed light on the taxonomy of controversial taxa, which becomes especially relevant regarding vector species

Phylogeography and demographic history of the Chagas disease vector Rhodnius nasutus (Hemiptera: Reduviidae) in the Brazilian Caatinga biome.

BACKGROUND:Rhodnius nasutus, a vector of the etiological agent Trypanosoma cruzi, is one of the epidemiologically most relevant triatomine species of the Brazilian Caatinga, where it often colonizes rural peridomestic structures such as chicken coops and occasionally invades houses. Historical colonization and determination of its genetic diversity and population structure may provide new information towards the improvement of vector control in the region. In this paper we present thoughtful analyses considering the phylogeography and demographic history of R. nasutus in the Caatinga. METHODOLOGY/PRINCIPAL FINDINGS:A total of 157 R. nasutus specimens were collected from Copernicia prunifera palm trees in eight geographic localities within the Brazilian Caatinga biome, sequenced for 595-bp fragment of the mitochondrial cytochrome b gene (cyt b) and genotyped for eight microsatellite loci. Sixteen haplotypes were detected in the cyt b sequences, two of which were shared among different localities. Molecular diversity indices exhibited low diversity levels and a haplotype network revealed low divergence among R. nasutus sequences, with two central haplotypes shared by five of the eight populations analyzed. The demographic model that better represented R. nasutus population dynamics was the exponential growth model. Results of the microsatellite data analyses indicated that the entire population is comprised of four highly differentiated groups, with no obvious contemporary geographic barriers that could explain the population substructure detected. A complex pattern of migration was observed, in which a western Caatinga population seems to be the source of emigrants to the eastern populations. CONCLUSIONS/SIGNIFICANCE:R. nasutus that inhabit C. prunifera palms do not comprise a species complex. The species went through a population expansion at 12-10 ka, during the Holocene, which coincides with end of the largest dry season in South America. It colonized the Caatinga in a process that occurred from west to east in the region. R. nasutus is presently facing an important ecological impact caused by the continuous deforestation of C. prunifera palms in northeast Brazil. We hypothesize that this ecological disturbance might contribute to an increase in the events of invasion and colonization of human habitations

Spatial and Molecular Epidemiology of Giardia intestinalis Deep in the Amazon, Brazil

Submitted by Sandra Infurna ([email protected]) on 2017-02-09T15:39:53Z No. of bitstreams: 1 beatriz_nunes_etal_IOC_2016.pdf: 1599651 bytes, checksum: c6fe43adb7c313b98638c98b7590e84e (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2017-02-09T15:46:52Z (GMT) No. of bitstreams: 1 beatriz_nunes_etal_IOC_2016.pdf: 1599651 bytes, checksum: c6fe43adb7c313b98638c98b7590e84e (MD5)Made available in DSpace on 2017-02-09T15:46:52Z (GMT). No. of bitstreams: 1 beatriz_nunes_etal_IOC_2016.pdf: 1599651 bytes, checksum: c6fe43adb7c313b98638c98b7590e84e (MD5) Previous issue date: 2016Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ. Brasil / Fundação Oswaldo Cruz. Terezina, PI, Brasil.Current control policies for intestinal parasitosis focuses on soil-transmitted helminths, being ineffective against Giardia intestinalis, a highly prevalent protozoon that impacts children's nutritional status in developing countries. The objective of this study was to explore spatial and molecular epidemiology of Giardia intestinalis in children of Amerindian descent in the Brazilian Amazon

Gut Bacterial Diversity of Field and Laboratory-Reared <i>Aedes albopictus</i> Populations of Rio de Janeiro, Brazil

Background: The mosquito microbiota impacts different parameters in host biology, such as development, metabolism, immune response and vector competence to pathogens. As the environment is an important source of acquisition of host associate microbes, we described the microbiota and the vector competence to Zika virus (ZIKV) of Aedes albopictus from three areas with distinct landscapes. Methods: Adult females were collected during two different seasons, while eggs were used to rear F1 colonies. Midgut bacterial communities were described in field and F1 mosquitoes as well as in insects from a laboratory colony (>30 generations, LAB) using 16S rRNA gene sequencing. F1 mosquitoes were infected with ZIKV to determine virus infection rates (IRs) and dissemination rates (DRs). Collection season significantly affected the bacterial microbiota diversity and composition, e.g., diversity levels decreased from the wet to the dry season. Field-collected and LAB mosquitoes’ microbiota had similar diversity levels, which were higher compared to F1 mosquitoes. However, the gut microbiota composition of field mosquitoes was distinct from that of laboratory-reared mosquitoes (LAB and F1), regardless of the collection season and location. A possible negative correlation was detected between Acetobacteraceae and Wolbachia, with the former dominating the gut microbiota of F1 Ae. albopictus, while the latter was absent/undetectable. Furthermore, we detected significant differences in infection and dissemination rates (but not in the viral load) between the mosquito populations, but it does not seem to be related to gut microbiota composition, as it was similar between F1 mosquitoes regardless of their population. Conclusions: Our results indicate that the environment and the collection season play a significant role in shaping mosquitoes’ bacterial microbiota

Vector competence and feeding-excretion behavior of Triatoma rubrovaria (Blanchard, 1843) (Hemiptera: Reduviidae) infected with Trypanosoma cruzi TcVI.

BackgroundSeveral studies addressed changes on the insect vector behavior due to parasite infection, but little is known for triatomine bugs, vectors of Trypanosoma cruzi, the etiological agent of Chagas disease. We assessed infection rates and metacyclogenesis of T. cruzi (TcVI) in fifth-instar nymphs of Triatoma rubrovaria comparing with the primary vector Triatoma infestans. Also, biological parameters related to feeding-excretion behavior were evaluated aiming to identify which variables are most influenced by T. cruzi infection.Methodology/principal findingsFifth-instar nymphs of T. rubrovaria and T. infestans were fed on mice infected with T. cruzi (TcVI). We compared the presence and the number of parasite evolutive forms in excreta of both triatomine species at 30, 60 and 90 days post-infection (dpi) with traditional statistical analyses. Moreover, both species were analyzed through generalized linear models and multinomial logistic regression hypotheses for seven behavioral parameters related to host-seeking and feeding-excretion. Triatoma rubrovaria and T. infestans had similar overall infection and metacyclogenesis rates of T. cruzi TcVI in laboratory conditions. Regarding vector behavior, we confirmed that the triatomine's tendency is to move away from the bite region after a blood meal, probably to avoid being noticed by the vertebrate host. Interspecific differences were observed on the volume of blood ingested and on the proportion of individuals that excreted after the blood meal, revealing the higher feeding efficiency and dejection rates of T. infestans. The amount of ingested blood and the bite behavior of T. rubrovaria seems to be influenced by TcVI infection. Infected specimens tended to ingest ~25% more blood and to bite more the head of the host. Noteworthy, in two occasions, kleptohematophagy and coprophagy behaviors were also observed in T. rubrovaria.Conclusions/significanceLaboratory infections revealed similar rate of T. cruzi TcVI trypomatigotes in excreta of T. rubrovaria and T. infestans, one of the most epidemiological important vectors of T. cruzi. Therefore, TcVI DTU was able to complete its life cycle in T. rubrovaria under laboratory conditions, and this infection changed the feeding behavior of T. rubrovaria. Considering these results, T. rubrovaria must be kept under constant entomological surveillance in Rio Grande do Sul, Brazil

DENV-1 Titer Impacts Viral Blocking in <i>w</i>Mel <i>Aedes aegypti</i> with Brazilian Genetic Background

Several countries have been using Wolbachia deployments to replace highly competent native Aedes aegypti populations with Wolbachia-carrying mosquitoes with lower susceptibility to arboviruses such as dengue, Zika, and chikungunya. In Rio de Janeiro, Wolbachia deployments started in 2015 and still present a moderate introgression with a modest reduction in dengue cases in humans (38%). Here, we evaluated the vector competence of wild-type and wMel-infected Ae. aegypti with a Brazilian genetic background to investigate whether virus leakage could contribute to the observed outcomes in Brazil. We collected the specimens in three areas of Rio de Janeiro with distinct frequencies of mosquitoes with wMel strain and two areas with wild Ae. aegypti. The mosquitoes were orally exposed to two titers of DENV-1 and the saliva of DENV-1-infected Ae. aegypti was microinjected into wMel-free mosquitoes to check their infectivity. When infected with the high DENV-1 titer, the presence of wMel did not avoid viral infection in mosquitoes’ bodies and saliva but DENV-1-infected wMel mosquitoes produced lower viral loads than wMel-free mosquitoes. On the other hand, wMel mosquitoes infected with the low DENV-1 titer were less susceptible to virus infection than wMel-free mosquitoes, although once infected, wMel and wMel-free mosquitoes exhibited similar viral loads in the body and the saliva. Our results showed viral leakage in 60% of the saliva of wMel mosquitoes with Brazilian background; thus, sustained surveillance is imperative to monitor the presence of other circulating DENV-1 strains capable of overcoming the Wolbachia blocking phenotype, enabling timely implementation of action plans