The Influence of the pH and Salinity of Water in Breeding Sites on the Occurrence and Community Composition of Immature Mosquitoes in the Green Belt of the City of São Paulo, Brazil.

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. The primary objective of this study was therefore to investigate the influence of the physicochemical parameters of water in different types of aquatic habitats on the occurrence of mosquito species in two remnants of Atlantic Forest in the city of São Paulo, Brazil. Collections of immature mosquitoes and assessment of the physicochemical characteristics of the water in the collection sites were carried out for twelve months. The variation in species composition and occurrence with the measured physicochemical parameters and the type of breeding site was assessed using constrained ordination methods. The results indicate that there was a statistically significant difference in species composition as a function of the different types of aquatic habitats, and that pH had an influence on species occurrence even when the variance explained by the type of aquatic habitat was removed from the analysis. There was a statistically significant association between mosquito species occurrence and pH and salinity, and the former had a significant influence on the mosquito species collected regardless of the type of aquatic habitat, showing that the pH of the breeding site water is an important factor in driving mosquito population dynamics and species distribution.

Reemergence of Yellow Fever in Brazil: The Role of Distinct Landscape Fragmentation Thresholds.

Yellow Fever Virus (YFV) reemergence in Brazil was followed by human suffering and the loss of biodiversity of neotropical simians on the Atlantic coast. The underlying mechanisms were investigated with special focus on distinct landscape fragmentation thresholds in the affected municipalities. An ecological study in epidemiology is employed to assess the statistical relationship between events of YFV and forest fragmentation in municipal landscapes. Negative binomial regression model showed that highly fragmented forest cover was associated with an 85% increase of events of YFV in humans and simians (RR = 1.85, CI 95% = 1.24-2.75, p=0.003) adjusted by vaccine coverage, population size, and municipality area. Intermediate levels of forest cover combined with higher levels of forest edge densities contribute to the YFV dispersion and the exponential growth of YF cases. Strategies for forest conservation are necessary for the control and prevention of YF and other zoonotic diseases that can spillover from the fragmented forest remains to populated cities of the Brazilian Atlantic coast.

Relationship between vertical stratification and feeding habits of mosquito (Diptera: Culicidae) assemblages collected in conservation units in the green belt of the city of São Paulo, Brazil.

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. Adult mosquitoes were collected using CDC traps, aspiration and Shannon traps. After morphological identification, host blood in engorged females was analyzed by PCR with a vertebrate-specific primer set based on mitochondrial cytochrome b DNA of vertebrates commonly found in the two conservation units. Although a higher abundance of the species Anopheles cruzii and Culex nigripalpus was found in the canopy, blood not only from birds but also from humans and rodents was identified in these mosquitoes. In one of the units, Wyeomyia confusa and Limatus durhamii were found occupying mainly niches at ground level while Culex vaxus was frequently found in the canopy. Haemagogus leucocelaenus, the main vector of yellow fever, was found in low abundance at all collection points, particularly in the canopy. Species richness and composition tended to vary little between canopy and ground level in the same environment, but the abundance between canopy and ground level varied more depending on the species analyzed, the most abundant and frequent species exhibiting a predilection for the canopy. Even those mosquito species observed more frequently in the canopy did not show an association with hosts found in this stratum as most of the blood identified in these species was from humans, suggesting opportunist feeding behavior, i.e., feeding on the most readily available host in the environment. The two most common species in the study, An. cruzii and Cx. nigripalpus, may be able to act as bridge vectors for pathogens to circulate between the forest canopy and ground level.

Confirmation of the first report of Psammolestes tertius Lent and Jurberg, 1965 (Hemiptera, Reduviidae, Triatominae) in Paraná State, Brazil.

INTRODUCTION: This study confirms the occurrence of Psammolestes tertius Lent & Jurberg, 1965 (Hemiptera, Reduviidae, Triatominae) in the state of Paraná, Brazil. METHODS: In 2002, a male specimen of P. tertius was collected in the municipality of Porto Rico, Paraná, Brazil. RESULTS: This finding adds to the data on the geographical distribution of P. tertius from 14 to 15 known occurrences in Brazilian states and, therefore, reports the increase in the diversity of triatomines in Paraná. CONCLUSIONS: The presence of P. tertius in the state of Paraná demonstrates that the biodiversity of these insects may have been underestimated.

Complexity of malaria transmission dynamics in the Brazilian Atlantic Forest.

Plasmodium malariae and Plasmodium vivax are protozoan parasites that can cause malaria in humans. They are genetically indistinguishable from, respectively, Plasmodium brasilianum and Plasmodium simium, i.e. parasites infecting New World non-human primates in South America. In the tropical rainforests of the Brazilian Atlantic coast, it has long been hypothesized that P. brasilianum and P. simium in platyrrhine primates originated from P. malariae and P. vivax in humans. A recent hypothesis proposed the inclusion of Plasmodium falciparum into the transmission dynamics between humans and non-human primates in the Brazilian Atlantic tropical rainforest. Herein, we assess the occurrence of human malaria in simians and sylvatic anophelines using field-collected samples in the Capivari-Monos Environmental Protection Area from 2015 to 2017. We first tested simian blood and anopheline samples. Two simian (Aloutta) blood samples (18%, n = 11) showed Plasmodium cytb DNA sequences, one for P. vivax and another for P. malariae. From a total of 9,416 anopheline females, we found 17 pools positive for Plasmodium species with a 18S qPCR assay. Only three showed P. cytb DNA sequence, one for P. vivax and the others for rodent malaria species (similar to Plasmodium chabaudi and Plasmodium berghei). Based on these results, we tested 25 rodent liver samples for the presence of Plasmodium and obtained P. falciparum cytb DNA sequence in a rodent (Oligoryzomys sp.) liver. The findings of this study indicate complex malaria transmission dynamics composed by parallel spillover-spillback of human malaria parasites, i.e. P. malariae, P. vivax, and P. falciparum, in the Brazilian Atlantic forest.

Phenotypic and genetic variation of Triatoma costalimai (Hemiptera: Reduviidae)

Abstract 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. We compared 16S sequences with those of putative Bolivian T. costalimai and its sister species, T. jatai. RESULTS: Brazilian populations had different connexivum color patterns and forewing shapes. A 16S mtDNA haplotype network showed a clear separation of Brazilian T. costalimai from both T. jatai and Bolivian T. costalimai. CONCLUSIONS: We report considerable variability in T. costalimai populations.

Confirmation of the first report of Psammolestes tertius Lent and Jurberg, 1965 (Hemiptera, Reduviidae, Triatominae) in Paraná State, Brazil

Abstract INTRODUCTION This study confirms the occurrence of Psammolestes tertius Lent & Jurberg, 1965 (Hemiptera, Reduviidae, Triatominae) in the state of Paraná, Brazil. METHODS: In 2002, a male specimen of P. tertius was collected in the municipality of Porto Rico, Paraná, Brazil. RESULTS: This finding adds to the data on the geographical distribution of P. tertius from 14 to 15 known occurrences in Brazilian states and, therefore, reports the increase in the diversity of triatomines in Paraná. CONCLUSIONS: The presence of P. tertius in the state of Paraná demonstrates that the biodiversity of these insects may have been underestimated.

Phenotypic and genetic variation of Triatoma costalimai (Hemiptera: Reduviidae).

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. We compared 16S sequences with those of putative Bolivian T. costalimai and its sister species, T. jatai. RESULTS: Brazilian populations had different connexivum color patterns and forewing shapes. A 16S mtDNA haplotype network showed a clear separation of Brazilian T. costalimai from both T. jatai and Bolivian T. costalimai. CONCLUSIONS: We report considerable variability in T. costalimai populations.

Detection of Zika and dengue viruses in wild-caught mosquitoes collected during field surveillance in an environmental protection area in São Paulo, Brazil.

Species of the genus Flavivirus are widespread in Brazil and are a major public health concern. The country's largest city, São Paulo, is in a highly urbanized area with a few forest fragments which are commonly used for recreation. These can be considered to present a potential risk of flavivirus transmission to humans as they are home simultaneously to vertebrate hosts and mosquitoes that are potential flavivirus vectors. The aim of this study was to conduct flavivirus surveillance in field-collected mosquitoes in the Capivari-Monos Environmental Protection Area (EPA) and identify the flavivirus species by sequence analysis in flavivirus IFA-positive pools. Monthly mosquito collections were carried out from March 2016 to April 2017 with CO2-baited CDC light traps. Specimens were identified morphologically and grouped in pools of up to 10 individuals according to their taxonomic category. A total of 260 pools of non-engorged females were inoculated into C6/36 cell culture, and the cell suspensions were analyzed by indirect immunofluorescence assay (IFA) after the incubation period. IFA-positive pools were tested by qRT-PCR with genus-specific primers targeting the flavivirus NS5 gene to confirm IFA-positive results and sequenced to identify the species. Anopheles cruzii (19.5%) and Wyeomyia confusa (15.3%) were the most frequent vector species collected. IFA was positive for flaviviruses in 2.3% (6/260) of the sample pools. This was confirmed by qRT-PCR in five pools (83.3%). All five flavivirus-positive pools were successfully sequenced and the species identified. DENV serotype 2 (DENV-2) was detected in Culex spp. and Culex vaxus pools, while ZIKV was identified in An. cruzii, Limatus durhamii and Wy. confusa pools. To the best of our knowledge, detection of flavivirus species of medical importance has never previously been reported in these species of wild-caught mosquitoes. The finding of DENV-2 and ZIKV circulating in wild mosquitoes suggests the existence of an enzootic cycle in the area. In-depth studies of DENV-2 and ZIKV, including investigation of mosquito infection, vector competence and infection in sylvatic hosts, are needed to shed light on the transmission dynamics of these important viruses and the potential risk of future outbreaks of DENV-2 and ZIKV infections in the region.

Diversity analysis and an updated list of mosquitoes (Diptera: Culicidae) found in Cantareira State Park, São Paulo, Brazil.

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. From October 2015 to April 2017, adult mosquitoes were collected with CDC traps, hand-held battery-powered aspirators and Shannon traps, and larvae and pupae were collected with larval dippers and suction samplers in natural and artificial breeding sites. In total, 11,038 specimens distributed in 103 taxa represented by 16 genera were collected. Both the observed species richness and diversity were greater in the environments with the highest degree of preservation. The 'wild' (most preserved) area in CSP had the greatest species richness, followed by the transition area and human-impacted area. The estimated richness indicated that the three environments may have a greater number of species than observed in this study, and Sorensen's index showed that the average degree of similarity varies little between areas. In the inventory of local species, the Shannon trap was the most efficient collection technique for adult mosquitoes, and the suction sampler the most efficient for immatures. The results highlight the increase in the number of different taxa collected as different mosquito capture techniques were included, confirming the importance of using several strategies to sample the local mosquito fauna satisfactorily when exploring a greater number of ecotopes. CSP is a refuge and shelter for native and introduced mosquito species where new biocenoses including pathogens, vertebrate hosts and vectors can form, allowing zoonotic outbreaks in the local human population to occur.

Influence of water's physical and chemical parameters on mosquito (Diptera: Culicidae) assemblages in larval habitats in urban parks of São Paulo, Brazil.

Water's physical and chemical characteristics are important constraints in aquatic ecosystems, acting on the development, survival, and adaptation of different organisms. Immature forms of mosquitoes develop in widely diverse aquatic environments and are mainly found in permanent or temporary freshwater bodies with little or no movement. The current study aimed to investigate whether variations in larval habitats' pH, salinity, dissolved oxygen, and water temperature influence the composition of Culicidae assemblages and the presence and abundance of Aedes albopictus and Ae. aegypti. From August 2012 to July 2013, captures of immature forms and measurement of water's physical and chemical profiles were performed monthly in natural and artificial breeding sites in four urban parks in the city of São Paulo, Brazil. Changes in species composition related to the parameters' variation were assessed by multivariate analysis. Regression trees were performed to evaluate the effect of breeding sites' physical and chemical variations on the presence and abundance of Ae. albopictus and Ae. aegypti. The observations suggest ranges of conditions for the measured variables in which most species tend to be found more frequently, and pH and salinity are the variables most closely associated with variations in mosquito composition. Ae. aegypti and Ae. albopictus were present in both natural and artificial breeding sites and were observed under significantly varying conditions of pH, salinity, dissolved oxygen, and temperature. For Ae. albopictus, larval habitat type and pH were the best predictors of incidence and abundance. For Ae. aegypti, pH and salinity were the best predictors of abundance, while dissolved oxygen and larval habitat type were better predictors of presence. This information broadens our understanding of the ecology and interaction of the investigated species with abiotic factors in the aquatic environments, providing useful data for studies that seek to elucidate the underlying mechanisms of selection and colonization of breeding sites by these mosquitoes. This study also reinforces previous observations indicating that Ae. albopictus and Ae. aegypti can colonize diverse types of larval habitats with widely varying physical and chemical conditions.

Influence of landscape composition and configuration on the richness and abundance of potential sylvatic yellow fever vectors in a remnant of Atlantic Forest in the city of São Paulo, Brazil.

The landscape's structure can play a relevant role in epidemic patterns of arboviruses, influencing factors such as abundance, movement, and dispersal ability in arthropod vectors and vertebrate hosts, besides promoting alterations in the rate of potential infectious contacts between these organisms. In the Americas, yellow fever (YF) exhibits only the sylvatic cycle, in which the virus circulates in sylvatic areas among non-human primates, being transmitted by mosquitoes of the Haemagogus and Sabethes genera. In this study, we investigate some aspects of the landscape in relation to diversity and abundance of culicid species associated with YF transmission. Studies were performed in the Cantareira State Park, a remnant of the Atlantic Forest located in Greater Metropolitan São Paulo, Brazil, where the YF virus circulated recently with dozens of deaths in howler monkeys (Alouatta guariba), in addition to reported human cases. Mosquito collections were carried out monthly from February 2015 to April 2017. Mosquitoes were collected from three sites using battery-powered aspirator (12-volt battery), CDC, and Shannon traps for adults, and suction samplers and entomological spoons in breeding sites to collect immature forms. 703 mosquitoes belonging to 12 species of the Aedini and Sabethini tribes were collected. Aedes scapularis and Psorophora ferox exhibited higher abundance, while Haemagogus leucocelaenus, the main vector of YF in São Paulo state, showed lower abundance in all sampled areas. The site with longer edge between forest area and anthropic area presented more richness and abundance of YF vector species, while the site with larger forest cover area and shorter edges between forest and anthropic areas exhibited an inverse pattern. Statistically significant differences were observed between the composition of potential YF vector species among the investigated sites. Although Hg. leucocelaenus occurred in all sampled sites, the different patterns of distribution and abundance of other mosquitoes such as Aedes scapularis and Psorophora ferox suggest that these species may be involved in the transmission of sylvatic YF in the study area.

Distribution of Culex (Microculex) (Diptera: Culicidae) in forest cover gradients.

Microculex is a subgenus of wild mosquitoes belonging to genus Culex, closely related to preserved environments. Its immature forms are generally associated with natural breeding sites, especially bromeliads. Recent years have witnessed the presence of some Microculex species in anthropic environments, including immature forms in artificial breeding sites, which may represent an adaptive tendency. This study aimed to investigate the variation in the abundance and dispersal of Microculex species in environments with different forest cover proportions. Three sites with different proportions of plant cover (60%, 70%, and 90%) were selected in an environmental protection area in the city of São Paulo, with varying degrees of modification and human presence. Collection was performed from March 2015 to April 2017, targeting bromeliads and artificial containers. Variations in the species' richness, composition, and abundance in different environments were analyzed. Variations in mean abundance and larval density between the different forest cover gradients were analyzed with generalized linear mixed-effects models. A total of 1,028 specimens belonging to 14 species were collected. Richness and composition were similar across the environments. Culex (Mcx.) imitator and Cx. (Mcx.) pleuristriatus were the most abundant species. The results showed a relationship between forest cover reduction and an increase in larval abundance and density for Cx. (Mcx.) pleuristriatus. Cx. (Mcx.) imitator showed a decrease in larval abundance related to a reduction in forest cover. Species from Pleuristriatus Series were found both in bromeliads and in artificial breeding sites. The findings emphasize that the Microculex Group of mosquitoes is not limited to preserved environments, but that some species such as Cx. (Mcx.) pleuristriatus appear to be well-adapted to areas impacted by human activity, colonizing artificial breeding sites, which may suggest a possible domiciliation process.

Effects of anthropogenic landscape changes on the abundance and acrodendrophily of Anopheles (Kerteszia) cruzii, the main vector of malaria parasites in the Atlantic Forest in Brazil.

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. In this study, it was hypothesized that factors associated with anthropogenic landscape changes may be responsible for the variation in abundance and acrodendrophily observed in An. cruzii. METHODS: The study was conducted in a conservation unit in the city of São Paulo, Brazil. Monthly entomological collections were performed from March 2015 to April 2017, and the resulting data were used with data from another study conducted in the same area between May 2009 and June 2010. Mosquitoes were collected from five sites using CDC and Shannon traps. Landscape composition and configuration metrics were measured, and generalized linear mixed-effect models were used to investigate the relationship between these metrics and variations in the abundance and acrodendrophily of An. cruzii. RESULTS: The model that showed the best fit for the relationship between landscape metrics and An. cruzii abundance suggests that an increase in the proportion of forest cover leads to an increase in the abundance of this mosquito, while the model that best explained variations in An. cruzii acrodendrophily suggests that an increase in total forest-edge length leads to greater activity by this species at ground level. CONCLUSION: While the data indicate that changes in landscape due to human activities lead to a reduction in An. cruzii abundance, such changes may increase the contact rate between this species and humans living on the edges of forest fragments where An. cruzii is found. Future studies should, therefore, seek to elucidate the effect of these landscape changes on the dynamics of Plasmodium transmission in the Atlantic Forest, which according to some studies includes the participation of simian hosts.

Occurrences of triatomines (Hemiptera: Reduviidae) and first reports of Panstrongylus geniculatus in urban environments in the city of Sao Paulo, Brazil.

This note reports on occurrences of triatomine species in the city of Sao Paulo, Brazil, registered between 1988 and 2017. Records of triatomines captured in Sao Paulo are based on specimens received spontaneously from Health Surveillance Centers, Health Centers and Zoonosis Control Centers in the city as well as from citizens. Species were identified morphologically at the Public Health Entomology Laboratory, Faculty of Public Health, University of Sao Paulo, where the triatomines, which are vectors of Chagas disease, were tested for Trypanosoma cruzi infection. The first reported occurrence of triatomine bugs in urban Sao Paulo was in 1988. The specimen, which was captured in Jardim Sao Luiz district, was from the genus Panstrongylus and was registered as Panstrongylus sp. but was not sexed. Since this first recorded occurrence, the following species have been found in the city: Panstrongylus geniculatus (2 occurrences), P. megistus (15 occurrences), Triatoma infestans (1 occurrence) and T. sordida (3 occurrences). In this paper, the importance of reporting occurrences of triatomine bugs in the city of Sao Paulo, one of the largest metropolis in the world, is discussed with an emphasis on P. megistus. The occurrences discussed here indicate the importance of entomological surveillance for these vectors even in urban centers although the possibility of vector transmission of Chagas disease in these centers is very low.

Catalog of the entomologic collections of the Faculty of Public Health of the University of Sao Paulo - (2nd series ii): Triatominae (Hemiptera, Reduviidae).

This article reports a list with 912 specimens of the subfamily Triatominae deposited in the Entomological Collection of the Faculty of Public Health of the University of Sao Paulo. The collection is composed of 1 holotype, 3 alotypes, 15 paralectotypes, 77 paratypes, distributed in 5 tribes and 12 genera: Tribus Alberprosenini: genus Alberprosenia Martinez & Carcavallo, 1977; Tribus Bolboderini: genus Microtriatoma Prosen & Martinez, 1952; Tribus Cavernicolini: genus Cavernicola Barber, 1937; Tribus Rhodnini: genus Psammolestes Bergroth, 1941; genus Rhodnius Stal, 1859; Tribus Triatomini: genus Dipetalogaster Usinger 1939; genus Eratyrus Stal 1859; genus Hermanlentia Jurberg & Galvão, 1997; genus Linshcosteus Distant, 1904; 1944; genus Panstrongylus Berg 1879; genus Paratriatoma Barber 1938; genus Triatoma Laporte 1833.

Occurrences of Phlebotomine Sand Flies (Diptera: Psychodidae) Potentially Associated with Leishmaniasis Transmission in Urban Parks in the City of São Paulo, Brazil.

A study of the phlebotomine sand flies was carried out between October 2011 and June 2013 in municipal parks in the city of São Paulo. A total of 173 specimens of 5 species were collected (Psychodopygus lloydi, Pintomyia fischeri, Lutzomyia amarali, Nyssomyia whitmani, and Migonemyia migonei). Three of these species may be involved in the transmission of the causative agent of tegumentary leishmaniasis. Surveillance and monitoring phlebotomine species from these areas are crucial as measure of prevention and control of leishmaniasis.

Mosquitoes in urban green spaces: using an island biogeographic approach to identify drivers of species richness and composition.

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. Using the equilibrium theory of island biogeography, we tested predictive models for species richness and composition and performed nestedness analysis. We also investigated whether species loss tends to benefit vector mosquitoes. In the period 2011 to 2013, a total of 37,972 mosquitoes belonging to 73 species and 14 genera were collected. Our results suggest there is a species-area relationship, an increase in species similarity as richness is lost and a nested species composition pattern. Seven of the eight most commonly found species are considered vectors of human pathogens, suggesting a possible link between species loss and increased risk of pathogen transmission. Our data highlight the need for studies that seek to understand how species loss may affect the risk of infectious diseases in urban areas.

Mosquito Population Diversity and Abundance Patterns In Two Parks In São Paulo, Brazil.

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. Our findings suggest that both climatic and density-dependent variations may have an important impact on fluctuations in mosquito abundance, modulating population dynamics in urban parks.