Hélcio R. Gil-Santana

SCANNING ELECTRON MICROSCOPY OF EGGS OF OCHLEROTATUS (PROTOMACLEAYA) TERRENS WALKER

ABSTRACT Observations on the morphological ultrastructure of eggs of Ochlerotatus (Protomacleaya) terrens (Diptera: Culicidae) were conducted by using scanning electron microscopy. Morphometry of the principal structures was obtained with the aid of Semafore analysis software. Eggs of Oc. terrens from females caught in the Biological Reserve of Tinguá, State of Rio de Janeiro, Brazil, were utilized. The eggs presented elliptical outlines, with a length of approximately 649.0 μm and width of 168.7 μm. The egg index (length to width ratio) was 3.85 μm. The exochorion had hexagonal and sometimes pentagonal ornamentation. Inside the chorionic cells were small, well-distributed tubercles with a large range of sizes. The micropylar apparatus, located in the anterior region of the egg, presented a collar with a poorly visible frame, with borders of indeterminate extent and margins without a defined transition area, and a thickness of approximately 1.8 μm. The micropyle was plugged.

Preliminary investigation of Culicidae species in South Pantanal, Brazil and their potential importance in arbovirus transmission

In view of the high circulation of migratory birds and the environmental and climatic conditions which favor the proliferation of arthropods, the Brazilian Pantanal is susceptible to circulation of arboviruses. However, the amount of data concerning arbovirus vectors in this area is scarce; therefore the aim of this study was to conduct a preliminary investigation of Culicidae species in the Nhecolândia Sub-region of South Pantanal, Brazil and their potential importance in the arbovirus transmission. A total of 3684 specimens of mosquitoes were captured, 1689 of which caught in the rainy season of 2007, were divided into 78 pools and submitted to viral isolation, Semi-Nested RT-PCR and Nested RT-PCR, with a view to identifying the most important arboviruses in Brazil. Simultaneously, 70 specimens of ticks found blood-feeding on horses were also submitted to the same virological assays. No virus was isolated and viral nucleic-acid detection by RT-PCR was also negative. Nevertheless, a total of 22 Culicidae species were identified, ten of which had previously been reported as vectors of important arboviruses. The diversity of species found blood-feeding on human and horse hosts together with the arboviruses circulation previously reported suggest that the Nhecolândia Sub-region of South Pantanal is an important area for arbovirus surveillance in Brazil.

Culicidae community composition and temporal dynamics in Guapiacu Ecological Reserve, Cachoeiras de Macacu, Rio de Janeiro, Brazil.

A temporal observational study was conducted of the Culicidae fauna in a remnant area of Atlantic Forest within a private reserve (Guapiaçu Ecological Reserve-REGUA) presenting typical vegetation cover of dense rain forest, with some patches recovering a floristic composition similar to that of the original community. Research was carried out to analyze the influence of climatic factors (mean monthly temperature, rainfall, and air relative humidity) on the temporal dynamics of the mosquito communities that occur in the reserve. The completeness of the mosquito inventory was assessed with individual-based rarefaction-extrapolation curves. Differences in species composition between sites and months were tested with PERMANOVA. True diversities of orders 0, 1, and 2 (effective numbers) were estimated and compared between sites, months, and years. Multiple stepwise regressions were used to assess relationships between climatic variables, measures of diversity, and abundances of the most common species. There were significant interactive effects between year and site on measures of diversity. However, diversity estimates showed little variation among months, and these were weakly correlated with climatic variables. Abundances of the most common species were significantly related to temperature or relative humidity, but not rainfall. The presence of mosquito species known to be vectors of human diseases combined with an intermittent flow of visitors to the study area suggests there is a risk of disease transmission that warrants further monitoring.

Vertical oviposition activity of mosquitoes in the Atlantic Forest of Brazil with emphasis on the sylvan vector, Haemagogus leucocelaenus (Diptera: Culicidae)

ABSTRACT: n This study aimed to assess the vertical patterns of oviposition and temporal changes in the distribution of mosquito species in an area of the Atlantic Forest in Rio de Janeiro State, Brazil, and in particular, the behavior and oviposition of potential yellow fever virus vectors. Mosquito samples were collected from the Ecological Reserve Guapiaçu (REGUA, Brazil), which includes a somewhat disturbed forest, with a large diversity of plants and animals. In all, 5,458 specimens (ten species from seven genera) were collected. Haemagogus leucocelaenus was the most frequently captured species, representing 73% of the specimens collected. Species richness and diversity were the highest in the samples collected from the ground-level ovitraps and decreased with height. Species composition also differed significantly among heights. The largest species differences were detected between ovitraps set at the ground level and those set at 7 m and 9 m; Hg. leucocelaenus, Limatus durhamii, and Limatus paraensis contributed most to these differences. Sampling month and climatic variables had significant effects on species richness and diversity. Species diversity and richness decreased with height, suggesting that the conditions for mosquito breeding are more favorable closer to the ground. Species composition also showed vertical differences.

Assassin Bugs (Reduviidae Excluding Triatominae)

Reduviidae is the largest family of predaceous terrestrial Heteroptera, with about 7,000 described species in 25 subfamilies, and is one of the three most speciose families within Hemiptera. A general overview on Neotropical members of this family is furnished, with an updated account on the taxonomy for each subfamily. Keys to genera of almost all subfamilies are presented.

Immature mosquitoes (Diptera: Culicidae) in a eutrophic landfill tank from State of Rio de Janeiro, Brazil

INTRODUCTIONnTo determine the faunal composition of immature culicids inhabiting a percolation tank in the landfill of Sapucaia, State of Rio de Janeiro, Brazil, immature mosquitoes were collected over a two-day period during the third weeks of April, August and October 2011.nnnRESULTSnThe species found were Culex usquatus, Lutzia bigoti, Anopheles argyritarsis and Limatus durhamii. This study is the first to report the colonization of eutrophic breeding sites by these species.nnnCONCLUSIONSnThe oviposition behavior observed in this study suggests a secondary adaptation or change in habit to select eutrophic environments during the developmental stages of the observed species.

Diversity of yellow fever mosquito vectors in the Atlantic Forest of Rio de Janeiro, Brazil

INTRODUCTIONnEnvironmental modifications caused by human activities have led to changes in mosquito vector populations, and sylvatic species have adapted to breeding in urban areas.nnnMETHODSnMosquitoes were collected using ovitraps in three sampling sites in the Atlantic Forest in the State of Rio de Janeiro, Brazil.nnnRESULTSnWe collected 2,162 Culicidae specimens. Haemagogus janthinomys and Haemagogus leucocelaenus, both sylvatic yellow fever virus vectors, were the most common species found.nnnCONCLUSIONnThere is a potential for the transmission of arboviruses in and around these natural reserves. Therefore, it is necessary to maintain entomological surveillance programs in the region.

Mosquito Communities in Nova Iguaçu Natural Park, Rio de Janeiro, Brazil

Abstract In order to gather information on the culicid fauna of Nova Iguaçu Municipal Park, Rio de Janeiro, Brazil, adult and immature stages were collected with the Centers for Disease Control and Prevention miniature light traps, and dippers and suction tubes, respectively. In all, 828 adult and 990 immature specimens were collected belonging to 12 genera. Among the species collected were Aedes aegypti, Ae. albopictus, Ae. fluviatilis, Ae. scapularis, Haemagogus leucocelaenus, and Psorophora ferox that are considered of potential medical importance. Culicids used a variety of larval habitats and bred under diverse ecological conditions, mostly in natural water containers formed by bamboo, bromeliad, ground depression, rock pool, stream, tree hole, and in artificial containers such as abandoned bathtub, car carcass, abandoned sink, plastic cup, waste tire, and water tank. Species richness and diversity increased from lower to higher forest cover and was highest in sites with highest diversity and high number of larval habitats.

Biodiversity and Temporal Distribution of Immature Culicidae in the Atlantic Forest, Rio de Janeiro State, Brazil.

To increase the knowledge of biodiversity and identify larval habitats used by immature mosquitoes in the Atlantic Forest, we conducted a study in areas with various stages of preservation within the Guapiaçu Ecological Reserve in Cachoeiras de Macacu, Rio de Janeiro state. The Culicidae fauna were sampled during February, April, June, August, October, and December 2012; February, March, April, May, June, August, October, and December 2013; and January and March 2014. Immature mosquitoes were collected with dippers and suction tubes (mouth aspirators). Over the sampling period, 2697 larvae of 56 species were collected, some of which are recognized vectors of human diseases. The larval mosquito community found in artificial habitats, temporary ground water, and phytotelmata differed between sites, except for the mosquito fauna in bromeliads, which were almost 80% similar. Species segregation was more evident between larval habitats than between sites. Culex usquatus was the dominant species and colonized the highest number of larval habitats. The artificial larval habitats found in REGUA were colonized by a great diversity of species and high abundance as well, thus human artifacts left by the public in the area that collect water may promote an increase in mosquito populations. Among the species collected, some are known or suspected vectors of pathogens to humans and/or veterinary relevance, and their medical relevance is discussed.

Natural infection by Trypanosoma cruzi in triatomines and seropositivity for Chagas disease of dogs in rural areas of Rio Grande do Norte, Brazil

INTRODUCTIONnChagas disease is caused by the protozoa Trypanosoma cruzi. Its main reservoir is the domestic dog, especially in rural areas with favorable characteristics for vector establishment and proliferation. The aims of this study were to collect data, survey and map the fauna, and identify T. cruzi infection in triatomines, as well as to assess the presence of anti-T. cruzi antibodies in dogs in rural areas of the municipality of Mossoró, Brazil.nnnMETHODSnAn active entomologic research was conducted to identify adult specimens through an external morphology dichotomous key. The analysis of natural infection by T. cruzi in the insects was performed by isolation in culture and polymerase chain reaction. The antibody testing for T. cruzi in dogs was performed by enzyme-linked immunosorbent assay and indirect immunofluorescence assay.nnnRESULTSnA total of 68 triatomines were captured, predominantly the Triatoma brasiliensis brasiliensis (Neiva 1911) species. The vector mapping displayed areas with greater risk for parasite transmission. Of the examined triatomines (51 specimens), 41.2% (21/51) were positive on polymerase chain reaction, and all were negative on culture. In the serum testing, 11% (25/218) of dogs were seropositive, but no association was found between the serologic results and the presence and infection by T. cruzi in triatomines.nnnCONCLUSIONSnThis study demonstrated the movement of T. cruzi in the studied area, by the presence of vectors and naturally infected domestic reservoirs. The mapping of the studied rural area demonstrates the risk of disease transmission.