Oviposition behavior of Haemagogus leucocelaenus (Diptera: culicidae), a vector of wild yellow fever in Brazil

Haemagogus leucocelaenus, which is considered a major vector of wild yellow fever, exhibits acrodendrophilic habits and mainly deposits its eggs in treeholes and bamboo internodes. The selection of nursery sites is essential in the life history and reproductive success of mosquitoes. The present work investigated the preferred oviposition height and period of Hg. leucocelaenus in an Atlantic forest area in Rio de Janeiro. Sampling was performed using oviposition traps that were placed on plant material at 0, 2, 4, 6, and 8 m above the ground, from August 2015 to July 2016. Eggs were more abundant during October and May, and the height of traps placement had no significant effect on the eggs number indicating that Hg. leucocelaenus explores different levels of forest habitats, a behavior that may favor the transmission of pathogens among arboreal animals including primates and humans. The findings of the present study are discussed from an ecological and epidemiological point of view

Yellow fever virus maintained by Sabethes mosquitoes during the dry season in Cerrado, a Semiarid Region of Brazil, in 2021

In recent decades, waves of yellow fever virus (YFV) from the Amazon Rainforest have spread and caused outbreaks in other regions of Brazil, including the Cerrado, a savannah-like biome through which YFV usually moves before arriving at the Atlantic Forest. To identify the vectors involved in the maintenance of the virus in semiarid environments, an entomological survey was conducted after confirmation of yellow fever (YF) epizootics at the peak of the dry season in the Cerrado areas of the state of Minas Gerais. In total, 917 mosquitoes from 13 taxa were collected and tested for the presence of YFV. Interestingly, mosquitoes of the Sabethes genus represented 95% of the diurnal captured specimens, displaying a peak of biting activity never previously recorded, between 4:30 and 5:30 p.m. Molecular analysis identified three YFV-positive pools, two from Sabethes chloropterus—from which near-complete genomes were generated—and one from Sa. albiprivus, whose low viral load prevented sequencing. Sa. chloropterus was considered the primary vector due to the high number of copies of YFV RNA and the high relative abundance detected. Its bionomic characteristics allow its survival in dry places and dry time periods. For the first time in Brazil, Sa. albiprivus was found to be naturally infected with YFV and may have played a role as a secondary vector. Despite its high relative abundance, fewer copies of viral RNA were found, as well as a lower Minimum Infection Rate (MIR). Genomic and phylogeographic analysis showed that the virus clustered in the sub-lineage YFVPA-MG, which circulated in Pará in 2017 and then spread into other regions of the country. The results reported here contribute to the understanding of the epidemiology and mechanisms of YFV dispersion and maintenance, especially in adverse weather conditions. The intense viral circulation, even outside the seasonal period, increases the importance of surveillance and YFV vaccination to protect human populations in affected areas

Serological evidence of orthopoxvirus infection in neotropical primates in Brazil

The genus Orthopoxvirus (OPXV) of the family Poxviridae comprises several viruses that are capable of infecting a wide range of hosts. One of the most widespread OPXVs is the Vaccinia virus (VACV), which circulates in zoonotic cycles in South America, especially in Brazil, infecting domestic and wild animals and humans and causing economic losses as well as impacting public health. Despite this, little is known about the presence and/or exposure of neotropical primates to orthopoxviruses in the country. In this study, we report the results of a search for evidence of OPVX infections in neotropical free-living primates in the state of Minas Gerais, southeast Brazil. The sera or liver tissues of 63 neotropical primates were examined through plaque reduction neutralization tests (PRNT) and real-time PCR. OPXV-specific neutralizing antibodies were detected in two sera (4.5%) from Callithrix penicillata, showing 55% and 85% reduction in plaque counts, evidencing their previous exposure to the virus. Both individuals were collected in urban areas. All real-time PCR assays were negative. This is the first time that evidence of OPXV exposure has been detected in C. penicillata, a species that usually lives at the interface between cities and forests, increasing risks of zoonotic transmissions through spillover/spillback events. In this way, studies on the circulation of OPXV in neotropical free-living primates are necessary, especially now, with the monkeypox virus being detected in new regions of the planet

Evaluation of the maize (Zea mays L.) diversity on the Archipelago of Madeira

The variability of 43 open-pollinated populations of maize (Zea mays L.), representing a wide range of ecological conditions on the Archipelago of Madeira, was evaluated based on the morphological and reproductive traits. Individual data of 41 traits related to earliness, plant and tassel structure and the shape of the ear and grain were analysed using multivariate analysis. The populations belonging to two major maize varieties were grouped into four groups by their degree of dissimilarity, based on discriminant analysis. The dissimilarity of these groups was confirmed by the values of the Tukey test. The racial rank of these groups was proposed and a brief description of the maize landraces was presented. This work represents the first morphological characterization and analysis of diversity of maize germplasm for the Archipelago of Madeira where the traditional agricultural practices are still keeping this Portuguese region free from corn hybrids. The description of the Madeiran corn landraces allows us to preserve the existing corn biodiversity and could be used for their registration as conservation landraces or for conservation and breeding proposes worldwide.Portuguese Foundation for the Science and Technology (FCT, Fundac¸a˜o para a Cieˆncia e Tecnologia) has sponsored this work, through the Centre of Macaronesian Studies (CEM) and the project POCTI no35003/AGR/2001. The Authors are grateful to the Madeiran farmers who assisted with collection of maize samples.info:eu-repo/semantics/publishedVersio

Identification of aluminum resistant genotypes among Madeiran regional wheats

Forty-eight genotypes representing wheat diversity from the Island of Madeira were screened for resistance to aluminum (Al) in nutrient solution. Seeds of wheat used in the experiments were obtained from local farmers. The soil pH and content of ionic Al of plots cultivated with wheat were analyzed. The pH of topsoils varied between 3.83 and 6.59. The amount of ionic Al in soil samples varied between 0.38 and 1.36 cmol Al3 + per kg of soil and was positively correlated with the altitude of a plot. Eriochrome cyanine staining was used to evaluate the effect of Al ions on the root elongation. Seventy-two hour exposure of 3-day-old seedlings to 100 and 200 mM Al in nutrient solution revealed a high number of Al resistant genotypes among wheat germplasm. After withdrawal of Al stress, survival and root regrowth was observed in 28 and 23 genotypes screened at 100 and 200 mM Al in nutrient solution, respectively. Enhanced resistance to Al among Madeiran genotypes was associated with the amount of ionic Al in the soils. Complexity and various patterns of responses of tested cultivars to Al stress may suggest that Madeiran germplasm could be a valuable source of genes controlling Al resistance for conventional breeding programs and for studies of molecular bases of mechanisms of Al resistance.Portuguese Foundation for the Science and Technology (FCT, Fundac¸o para a Cieˆncia e Tecnologia) has sponsored this work, through the Centre of Biological and Geological Sciences (C.C.B.G.) and the project POCTI/no. 33005/AGR/1999. The authors are also grateful to the Madeiran Centre of Science and Technology (CITMA) for financial support. Acknowledgements are due to Mr. Roge´rio Correia and Juan Silva for the technical assistance in conducting the laboratory and fieldwork and to Dr. Andrzej Aniol for valuable advice during preparation of this manuscript.info:eu-repo/semantics/publishedVersio

Inquérito sorológico do SARS-CoV-2 em trabalhadores de uma instituição de ensino e o retorno às atividades presenciais / SARS-CoV-2 serological survey of workers at an educational institution and the return to face-to-face activities

Em dezembro de 2019, uma nova doença denominada COVID-19 foi detectada e em março de 2020 foi declarada pandemia. O distanciamento social, principal medida preventiva, levou ao fechamento de setores da sociedade, inclusive o educacional, impactando escolas e universidades. Devido aos prejuízos causados no ensino-aprendizagem, aumentou-se a pressão pela volta ao ensino presencial. No entanto, na iminência do retorno, pouco se sabe sobre o estado imunológico dos servidores da educação. O objetivo desse trabalho foi realizar um inquérito sorológico nos funcionários de uma instituição de ensino, para mensurar o número de servidores expostos ao SARS-CoV-2. Foram aplicados 153 testes rápidos, e em sete (4,6%) foram detectados anticorpos. Os resultados evidenciaram que, mesmo após um ano de pandemia, era baixa proporção de trabalhadores com anticorpos anti-SARS-CoV-2 detectáveis, o que poderia representar um risco para o retorno às aulas presenciais, justificando-se portanto a manutenção das atividades à distância, até que se atingisse altas taxas de cobertura vacinal entre a comunidade escolar.

Ecological and environmental factors affecting transmission of sylvatic yellow fever in the 2017-2019 outbreak in the Atlantic Forest, Brazil

Background: Yellow fever virus (YFV) is an arbovirus that, despite the existence of a safe and effective vaccine, continues to cause outbreaks of varying dimensions in the Americas and Africa. Between 2017 and 2019, Brazil registered un unprecedented sylvatic YFV outbreak whose severity was the result of its spread into zones of the Atlantic Forest with no signals of viral circulation for nearly 80 years. Methods: To investigate the influence of climatic, environmental, and ecological factors governing the dispersion and force of infection of YFV in a naïve area such as the landscape mosaic of Rio de Janeiro (RJ), we combined the analyses of a large set of data including entomological sampling performed before and during the 2017–2019 outbreak, with the geolocation of human and nonhuman primates (NHP) and mosquito infections. Results: A greater abundance of Haemagogus mosquitoes combined with lower richness and diversity of mosquito fauna increased the probability of finding a YFV-infected mosquito. Furthermore, the analysis of functional traits showed that certain functional groups, composed mainly of Aedini mosquitoes which includes Aedes and Haemagogus mosquitoes, are also more representative in areas where infected mosquitoes were found. Human and NHP infections were more common in two types of landscapes: large and continuous forest, capable of harboring many YFV hosts, and patches of small forest fragments, where environmental imbalance can lead to a greater density of the primary vectors and high human exposure. In both, we show that most human infections (~ 62%) occurred within an 11-km radius of the finding of an infected NHP, which is in line with the flight range of the primary vectors. Conclusions: Together, our data suggest that entomological data and landscape composition analyses may help to predict areas permissive to yellow fever outbreaks, allowing protective measures to be taken to avoid human cases

A New High-Throughput Tool to Screen Mosquito-Borne Viruses in Zika Virus Endemic/Epidemic Areas

International audienceMosquitoes 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 BioMark™ 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

The Genome of the Zoonotic Malaria Parasite Plasmodium simium Reveals Adaptions to Host-switching

Oral Session

The genome of the zoonotic malaria parasite Plasmodium simium reveals adaptations to host switching

BACKGROUND: Plasmodium simium, a malaria parasite of non-human primates (NHP), was recently shown to cause zoonotic infections in humans in Brazil. We sequenced the P. simium genome to investigate its evolutionary history and to identify any genetic adaptions that may underlie the ability of this parasite to switch between host species. RESULTS: Phylogenetic analyses based on whole genome sequences of P. simium from humans and NHPs reveals that P. simium is monophyletic within the broader diversity of South American Plasmodium vivax, suggesting P. simium first infected NHPs as a result of a host switch of P. vivax from humans. The P. simium isolates show the closest relationship to Mexican P. vivax isolates. Analysis of erythrocyte invasion genes reveals differences between P. vivax and P. simium, including large deletions in the Duffy-binding protein 1 (DBP1) and reticulocyte-binding protein 2a genes of P. simium. Analysis of P. simium isolated from NHPs and humans revealed a deletion of 38 amino acids in DBP1 present in all human-derived isolates, whereas NHP isolates were multi-allelic. CONCLUSIONS: Analysis of the P. simium genome confirmed a close phylogenetic relationship between P. simium and P. vivax, and suggests a very recent American origin for P. simium. The presence of the DBP1 deletion in all human-derived isolates tested suggests that this deletion, in combination with other genetic changes in P. simium, may facilitate the invasion of human red blood cells and may explain, at least in part, the basis of the recent zoonotic infections