Walter Ceretti-Junior

Diversity and abundance of mosquitoes (Diptera:Culicidae) in an urban park: larval habitats and temporal variation.

Urban parks are areas designated for human recreation but also serve as shelter and refuge for populations of several species of native fauna, both migratory and introduced. In Brazil, the effect of annual climate variations on Aedes aegypti and dengue epidemics in large cities like São Paulo is well known, but little is known about how such variations can affect the diversity of mosquito vectors in urban parks and the risk of disease transmission by these vectors. This study investigates the influence of larval habitats and seasonal factors on the diversity and abundance of Culicidae fauna in Anhanguera Park, one of the largest remaining green areas in the city of São Paulo. Species composition and richness and larval habitats were identified. Seasonality (cold-dry and hot-rainy periods) and year were considered as explanatory variables and the models selection approach was developed to investigate the relationship of these variables with mosquito diversity and abundance. A total of 11,036 specimens from 57 taxa distributed in 13 genera were collected. Culex nigripalpus, Cx. quinquefasciatus and Aedes albopictus were the most abundant species. Bamboo internodes and artificial breeding sites showed higher abundance, while ponds and puddles showed greater richness. Significant relationships were observed between abundance and seasonality, with a notable increase in the mosquitos abundance in the warm-rainy periods. The Shannon and Berger-Parker indices were related with interaction between seasonality and year, however separately these predictors showed no relationship with ones. The increased abundance of mosquitoes in warm-rainy months and the fact that some of the species are epidemiologically important increase not only the risk of pathogen transmission to people who frequent urban parks but also the nuisance represented by insect bites. The findings of this study highlight the importance of knowledge of culicid ecology in green areas in urban environments.

Mosquito Faunal Survey In a Central Park of the City of São Paulo, Brazil

Abstract A total of 2,582 specimens of mosquitoes of 16 taxonomic categories grouped into 5 genera (Aedes, Culex, Mansonia, Toxorhynchites, and Wyeomyia) were collected in a central park of São Paulo City, Brazil. It is crucial to include such an area in official entomological surveillance programs since this park has all the epidemiological characteristics needed to maintain an enzootic cycle of arboviruses.

Immature Mosquitoes in Bamboo Internodes in Municipal Parks, City of São Paulo, Brazil

Abstract We conducted an inventory of the mosquito fauna of the internodes of bamboo plants grown in municipal parks in the city of São Paulo, Brazil. During October 2010 to July 2013, a total of 8,541 immature stages belonging to 21 mosquito species were collected from bamboos over 61 municipal parks. Of these, Aedes albopictus was the most abundant species followed by Ae. aegypti found in broken bamboos in most parks. The former species was 7.2 times more abundant than the latter when both species shared the same habitat. Other species collected from bamboos included Culex quinquefasciatus and Haemagogus leucocelaenus. In bamboos with perforated internodes, species of the genus Wyeomyia were the most prevalent. Differences were also observed in species composition and abundance of mosquitoes collected in transversely broken bamboos and those collected from perforated bamboo internodes. Constant surveillance of these breeding sites is crucial due to the epidemiological importance of the species found. Furthermore, these breeding sites may help maintain some native wild mosquito populations along with a variety of other invertebrates found in these urban green areas.

Mosquito (Diptera: Culicidae) fauna in parks in greater São Paulo, Brazil

Municipal parks in the city of Sao Paulo, which are used for leisure purposes, contain remnants of the flora of the Atlantic Forest, as well as lakes and springs, and are home to mammals, birds and arthropods, some of which can be vectors of disease. The eastern side of the city has the largest population in Sao Paulo and twenty-four municipal parks. The aim of this study was to investigate Culicidae fauna in two parks on this side of the city and to determine which of the Culicidae species identified have the potential to act as bioindicators and vectors of human pathogens. Culicidae were collected monthly between March 2011 and February 2012 in Carmo Park and Chico Mendes Park with battery-powered aspirators, Shannon traps and CDC traps for adult mosquitoes, and larval dippers and suction samplers for immature mosquitoes. To confirm sample sufficiency, the EstimateS program was used to plot sample-based species accumulation curves and estimate total richness by the Jackknife 1 method. In all, 1,092 culicids from nine genera (Aedes, Anopheles, Coquillettidia, Culex, Limatus, Mansonia, Trichoprosopon, Toxorhynchites and Uranotaenia) and nineteen taxonomic units were collected in Carmo Park. Coquillettidia venezuelensis (Theobald 1912), Aedes scapularis (Rondani 1848) and Culex (Culex) spp. Linnaeus 1758 were the most abundant adults, and Culex (Melanoconion) spp. Theobald 1903 and Anopheles strodei Root 1926 the most abundant immature mosquitoes. In Chico Mendes Park 4,487 mosquitoes in six genera and eighteen taxonomic units were collected. Culex (Cux.) spp. and Ae. scapularis were the most abundant adults, and Ae. albopictus (Skuse 1984) the most abundant immature mosquitoes. The species accumulation curves in both parks were close to the asymptote, and the total richness estimate was close to the observed richness. Some culicid taxons are bioindicators of environmental conditions in the areas they inhabit. It is important to monitor native fauna in municipal parks in Sao Paulo as various species in this study were found to have vector competence and capacity to transmit pathogens, such as arboviruses.

Mosquito populations dynamics associated with climate variations.

Mosquitoes are responsible for the transmission of numerous serious pathogens. Members of the Aedes and Culex genera, which include many important vectors of mosquito-borne diseases, are highly invasive and adapted to man-made environments. They are spread around the world involuntarily by humans and are highly adapted to urbanized environments, where they are exposed to climate-related abundance drivers. We investigated Culicidae fauna in two urban parks in the city of São Paulo to analyze the correlations between climatic variables and the population dynamics of mosquitoes in these urban areas. Mosquitoes were collected monthly over one year, and sampling sufficiency was evaluated after morphological identification of the specimens. The average monthly temperature and accumulated rainfall for the collection month and previous month were used to explain climate-related abundance drivers for the six most abundant species (Aedes aegypti, Aedes albopictus, Aedes fluviatilis, Aedes scapularis, Culex nigripalpus and Culex quinquefasciatus) and then analyzed using generalized linear statistical models and the Akaike Information Criteria corrected for small samples (AICc). The strength of evidence in favor of each model was evaluated using Akaike weights, and the explanatory model power was measured by McFaddens Pseudo-R2. Associations between climate and mosquito abundance were found in both parks, indicating that predictive models based on climate variables can provide important information on mosquito population dynamics. We also found that this association is species-dependent. Urbanization processes increase the abundance of a few mosquito species that are well adapted to man-made environments and some of which are important vectors of pathogens. Predictive models for abundance based on climate variables may help elucidate the population dynamics of urban mosquitoes and their impact on the risk of disease transmission, allowing better predictive scenarios to be developed and supporting the implementation of vector mosquito control strategies.

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.

Biodiversidade de mosquitos (Diptera: Culicidae) nos parques da cidade de São Paulo I

Given the scarcity of information on mosquitoes (Diptera: Culicidae) in the city of Sao Paulo, led the authors to propose a project to investigate this group of insects in some of the green areas, represented by municipal parks. The captures were undertaken in 35 municipal parks in the south, north and central-west of the city, between October 2010 and February 2011, during daylight. Immature forms were collected from breeding places with entomological ladles and suction pumps and adults from resting places with electric aspirators (12V battery). The identification of the specimens was undertaken in the Culicid laboratory of the Faculdade de Saude Publica, Universidade de Sao Paulo. In this first phase of the project, a total of 5,129 specimens distributed in 11 genera and 41 taxonomic categories were captured. Culex (Cux) quinquefasciatus was the most abundant species. The genus Aedes was represented mainly by Ae. (Och) fluviatilis and Ae. (Ste) albopictus. Ae. (Ste) aegypti and Ae. (Och) scapularis were frequent in some parks. Other genera were less abundant. Of the parks investigated, 25.7% presented more than ten groups of species, notably the Anhanguera with 26; on the other hand, 57.1% had five or fewer groups. Despite the anthropic pressure on these environments, several culicid species make use of these habitats as refuges. It is recommended that these environments be kept under constant epidemiological surveillance as some of the species collected constitute public health threats as pathogen vectors to the human population.

Wing geometry of Triatoma sordida (Hemiptera: Reduviidae) populations from Brazil

Triatoma sordida has a widespread distribution in Argentina, Bolivia, Brazil, Paraguay, and Uruguay and is frequently found in peridomestic environments. We investigated size and shape variability of T. sordida wings across Brazil. Field-collected adults from twelve populations were studied. For each individual female, seven landmarks on the right wing were digitalized. Shape variables derived from Procrustes superimposition were used in Principal Component Analysis (PCA). Wing size and shape variations among populations was explored by means of ANOVA. Wing centroid size was significantly different among T. sordida populations; specimens from Bahia (East) were larger than those of Mato Grosso do Sul (West). PCA based on wing shape variables showed low wing shape variability. These results reinforce previous data showing low genetic variability among T. sordida populations from Brazil.

Haemagogus leucocelaenus and Other Mosquitoes Potentially Associated With Sylvatic Yellow Fever In Cantareira State Park In the São Paulo Metropolitan Area, Brazil

Abstract The aim of this work was to investigate whether Haemagogus leucocelaenus and other mosquito species associated with sylvatic transmission of yellow fever virus are present in Cantareira State Park (CSP) in the São Paulo Metropolitan Area (SPMA). From October 2015 to March 2016, adult mosquitoes were captured with the Centers for Disease Control and Prevention traps, manual battery-powered aspirators, and Shannon traps; larvae and pupae were collected in natural and artificial breeding sites. A total of 109 adult mosquito specimens and 30 immature forms belonging to 11 taxonomic categories in 4 genera (Aedes, Psorophora, Sabethes, and Haemagogus) were collected, including Hg. leucocelaenus, the main vector of yellow fever. The entomological findings of the present study indicate that the area is of strategic importance for yellow fever surveillance not only because of the significant numbers of humans and nonhuman primates circulating in CSP and its vicinity but also because it represents a potential route for the disease to be introduced to the SPMA.

Mitochondrial PCR-RFLP Assay to Distinguish Triatoma brasiliensis macromelasoma from Triatoma brasiliensis brasiliensis Subspecies (Hemiptera: Reduviidae).

Triatoma brasiliensis sensu lato (s.l.), the main vector of Chagas disease in northeastern Brazil, is a species complex comprising four species, one with two subspecies (T. brasiliensis brasiliensis, T. brasiliensis macromelasoma, T. juazeirensis, T. sherlocki, and T. melanica), and each taxon displaying distinct ecological requirements. In order to evaluate the genetic relationships among nine T. brasiliensis s.l. populations from northeastern Brazil, we analyzed their mitochondrial cytochrome c oxidase subunit 1 sequences and suggested a PCR-RFLP assay to distinguish between T. b. macromelasoma and T. b. brasiliensis subspecies. All the specimens were morphologically identified as T. b. brasiliensis. The resulting phylogenies identified two major clades that are congruent with the geographical populations studied. Based on collection sites and in accordance with type-location, one clade was identified as the subspecies T. b. macromelasoma. The second clade grouped T. b. brasiliensis populations. Restriction endonuclease sites were observed in the sequences and used in PCR-RFLP assays, producing distinct fingerprints for T. b. macromelasoma and T. b. brasiliensis populations. The results suggest that these are different species and that gene flow occurs only among T. b. brasiliensis populations, possibly associated with human activity in the area.