Publications by authors named "Antonio Ralph Medeiros-Sousa"

Sand flies are a group of insects (Diptera, Psychodidae, Phlebotominae) in which some species may transmit agents of leishmaniasis. This study aimed to analyze the sand fly fauna in urban parks in Rio Branco, capital of Acre state, addressing its diversity, infection by Leishmania, and food sources in sand fly females. The sand flies were collected with CDC-type automatic light traps installed in three urban parks in Rio Branco: Captain Ciríaco, Horto Florestal and Chico Mendes.

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The Capivari-Monos Environmental Protection Area (EPA) is located in the southern part of the São Paulo city Green Belt. Since the 1950s, this region has been affected by uncontrolled urban sprawl, resulting in a change in the ecological habits of some vector mosquitoes. Over the last two decades, cases of autochthonous bromeliad malaria associated with the presence of anopheline mosquitoes in the EPA have been recorded.

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Article Synopsis
  • Genetic diversity and population structure of a sylvatic vector for yellow fever virus in São Paulo vary based on agricultural land use and isolation of Atlantic Forest fragments.
  • High genetic diversity is found in areas with intense agricultural activity, while populations show signs of recent expansion, indicated by negative values in neutrality tests.
  • A strong correlation exists between population structuring and the spatial distance of sampled forest fragments, with coastal populations being more closely related than those in the northwest.
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The intense process of deforestation in tropical forests poses serious challenges for the survival of biodiversity, as well as for the human species itself. This scenario is supported by the increase in the incidence of epidemics of zoonotic origin observed over the last few decades. In the specific case of sylvatic yellow fever (YF), it has already been shown that an increase in the transmission risk of the causative agent (yellow fever virus - YFV) is associated with areas with a high degree of forest fragmentation, which can facilitate the spread of the virus.

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Intestinal parasites are a constant public health problem in the Amazon region, with a high prevalence of cases related to poor sanitary conditions. We investigated the sociodemographic and seasonal factors associated with human intestinal parasite infections in an area of the Western Amazon, Brazil, from September 2017 to August 2019. Data were collected using a database available at the Diagnostic Support Centre (Centro de Apoio ao Diagnóstico, CAD) of the Municipality of Rio Branco, on positive diagnoses for intestinal parasites.

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Intraspecific competition between mosquito larvae can affect several adult traits, particularly size. This study tested the hypothesis that intraspecific competition during the larval stage affects wing length in Ae. aegypti and Ae.

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and are protozoan parasites that can cause malaria in humans. They are genetically indistinguishable from, respectively, and , i.e.

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Man-made changes to the landscape play a crucial role in altering the epidemiologic patterns of infectious diseases, mainly as a result of pathogen spillover. Sylvatic yellow fever is ideally suited to modeling of this phenomenon as the risk of transmission of the disease as well as its circulation and dispersal are associated with forest fragmentation. In this study we investigated the temporal dispersal pattern of yellow fever virus (YFV) by means of confirmed cases of epizootics in non-human primates in municipalities in the state of São Paulo where there was no recommendation for vaccination in 2017.

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The physicochemical parameters of water, such as pH, salinity, conductivity, and total dissolved solids, can influence mosquito larval development, survival, and abundance. Therefore, it is important to elucidate how these factors influence mosquito occurrence. We hypothesized that the occurrence and community composition of immature mosquito species are driven not only by the availability of suitable aquatic habitats, but also by the physicochemical factors of these habitats.

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The species richness of Amazonian phlebotomines is considered to be one of the highest in the world. In the present study, we investigated the richness and diversity of phlebotomine fauna in Xapuri city, Acre state, Western Brazilian Amazonia, which is an area that is highly endemic for cutaneous leishmaniasis. Sand fly collections were performed monthly from August 2013 to July 2015 (288 h total of sampling effort) in intradomiciliary, peridomiciliary, and forested environments of two localities.

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São Paulo is one of the largest cities in the world and has several characteristics that favor a diversity of urban and wild mosquitoes. Little is known about how variations in mosquito diversity and feeding preferences for different hosts in different vegetation strata can influence the risk of pathogen transmission to humans. We investigated vertical stratification of mosquitoes and its relationship with vertebrate hosts in environments with different degrees of conservation in two conservation units in the city of São Paulo.

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Transmission foci of autochthonous malaria caused by Plasmodium vivax-like parasites have frequently been reported in the Atlantic Forest in Southeastern and Southern Brazil. Evidence suggests that malaria is a zoonosis in these areas as human infections by simian Plasmodium species have been detected, and the main vector of malaria in the Atlantic Forest, Anopheles (Kerteszia) cruzii, can blood feed on human and simian hosts. In view of the lack of models that seek to predict the dynamics of zoonotic transmission in this part of the Atlantic Forest, the present study proposes a new deterministic mathematical model that includes a transmission compartment for non-human primates and parameters that take into account vector displacement between the upper and lower forest strata.

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Introduction: We aimed to study intraspecific variation in Triatoma costalimai, a potential vector of Chagas disease present in Brazil and Bolivia.

Methods: We analyzed phenotypic (connexivum color patterns, wing morphometrics) and genetic variation (16S mtDNA) of three Brazilian T. costalimai populations.

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Article Synopsis
  • Flaviviruses are a significant public health issue in Brazil, especially in urban areas like São Paulo, where forests coexist with human activities, increasing the risk of transmission.
  • A study conducted from March 2016 to April 2017 involved collecting mosquitoes in the Capivari-Monos Environmental Protection Area to identify flavivirus species, using methods like morphological identification and qRT-PCR analysis.
  • The research found flaviviruses in 2.3% of mosquito pools, with DENV-2 identified in Culex spp. and ZIKV in Anopheles and Wyeomyia species, marking the first report of these viruses in these particular wild mosquito species.
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Cantareira State Park (CSP) is located in the Metropolitan Region of São Paulo, one of the most densely populated areas on the planet. Recently, a yellow-fever epidemic practically annihilated the howler monkey population in this park, and human infections were reported in the vicinity. As simian and human plasmodia also circulate in CSP, the present study sought to provide an update on the mosquito fauna in this park, including an analysis of the diversity in areas with different degrees of conservation and a comparison of the yields achieved with different collection techniques.

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Article Synopsis
  • * A study conducted over a year in São Paulo, Brazil, measured these water properties and their influence on mosquito larvae in both natural and artificial breeding sites.
  • * Results showed that different species have varying preferences; for Ae. albopictus, larval habitat type and pH were critical for predicting its abundance, while Ae. aegypti's abundance was more closely linked to pH and salinity.
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Article Synopsis
  • The study examines how landscape structure affects the transmission of yellow fever (YF) by influencing the abundance and movement of mosquito vectors and non-human primate hosts.
  • Conducted in Cantareira State Park, Brazil, the research involved collecting mosquito samples over a two-year period to analyze species diversity associated with YF transmission, revealing 703 mosquitoes from 12 species.
  • Results showed that the abundance of YF vectors varied by site, with different patterns of distribution observed, highlighting the complex relationship between landscape features and mosquito populations.
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The interior of caves usually presents climate, light, soil, flora and fauna that distinguish it from the external environment. Among the sandfly species found in caves, several may act as vectors of Leishmania spp. and others are a nuisance to humans due to their painful bites.

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Background: The mosquito Anopheles (Kerteszia) cruzii is the main vector of human and simian malaria in the Atlantic Forest. This species is usually abundant in the forests where it occurs, preferring to live and feed on canopies, behaviour known as acrodendrophily. However, in several studies and locations this species has been observed in high density near the ground in the forest.

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Background: 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.

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Mosquitoes are well known for their epidemiological importance as vectors of a wide range of human pathogens. Despite the many studies on medically important species, little is known about the diversity patterns of these insects in urban green spaces, which serve as shelter and refuge for many native and invasive species. Here, we investigate drivers of mosquito richness and composition in nine urban parks in the city of São Paulo, Brazil.

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In the Amazon region the phlebotomine fauna is considered one of the most diverse in the world. The use of Shannon traps may provide information on the anthropophily of the species and improve the traps' performance in terms of diversity and quantity of insects collected when white and black colored traps are used together. This study sought to verify the attractiveness of the traps to the phlebotomine species of the Brazilian Amazon basin using Shannon traps under these conditions.

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Temperature and rainfall are important drivers of mosquito abundance and have been used in previous studies as the basis for predictive models. To elucidate patterns of mosquito population dynamics in urban environments, the variation in mosquito abundance over a year and its association with climatic variables were analyzed. The Akaike information criterion was used to analyze the correlations between abundance and climate variables in mosquito populations collected in 2 urban parks: Alfredo Volpi Park and Burle Marx Park.

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