Vanderlei C. Silva

Diversidade de criadouros e tipos de imóveis freqüentados por Aedes albopictus e Aedes aegypti

OBJECTIVE To assess the diversity of oviposition containers and buildings where females of Aedes albopictus and Aedes aegypti can be found. METHODS A study was carried out in the city of Rio de Janeiro, Southern Brazil, between 2002 and 2003. Larvae in different types of buildings were investigated, and immature forms found were then sent to the laboratory for identification. The larval frequency for both mosquitoes was estimated in the oviposition containers available. The Breteau index and the building infestation index were calculated and differences were tested using the Chi-square test. RESULTS The types of buildings that were positive for Aedes albopictus and Aedes aegypti were: dwellings (83.9%); churches, schools, clubs (6.8%); vacant land (6.4%); and businesses (2.8%). Of 9,153 larvae collected, 12.0% were Aedes albopictus and 88.0% were Aedes aegypti. Aedes albopictus were mostly found in drains (25.4%); cans, bottles, empty bottles (23.9%); and plant vases (16.2%). Aedes aegypti was much more frequently found than Aedes albopictus (chi(2)=145.067; p<0.001). Both species were significantly more frequent in artificial than in natural oviposition containers (chi(2)=31.46; p<0.001). The building infestation index and Breteau index for Aedes albopictus were 0.3% and 0.28% in 2002 and 0.4% and 0.5 in 2003, respectively. For Aedes aegypti, they were 1.0%, 1.16 in 2002 and 3.5% and 4.35 in 2003, respectively. CONCLUSIONS The present study assessed the frequencies of Aedes albopictus and Aedes aegypti females in various types of oviposition containers and types of buildings. The abundant availability of artificial containers in dwellings, associated with the capacity of Ae. albopictus to be also found in natural oviposition containers, has greatly contributed for their gradual adaptation to human environment.

Moonlight and blood-feeding behaviour of Lutzomyia intermedia and Lutzomyia whitmani (Diptera:Psychodidae:Phlebotominae), vectors of American cutaneous leishmaniasis in Brazil

Lutzomyia intermedia (Lutz & Neiva, 1912) and L. whitmani (Antunes & Coutinho, 1939) (Diptera: Psychodidae: Phlebotominae), two important vectors of American cutaneous leishmaniasis in Brazil, occur in sympatry in the locality of Posse county, Petropolis municipality, state of Rio de Janeiro, Brazil. We investigated the influence of the lunar cycle on the frequency of specimens of the two species caught while attempting to bite the collectors and in CDC light traps. Analysis of the numbers of sand flies captured in different lunar phases for two consecutive years in the peridomestic site and forest shows that there is a significant positive correlation between moonlight intensity and the numbers of L. intermedia and L. whitmani females collected while blood-feeding, whereas the opposite was observed for the CDC traps.

Effect of Fruit and Leaves of Meliaceae Plants (Azadirachta indica and Melia azedarach) on the Development of Lutzomyia longipalpis Larvae (Diptera: Psychodidae: Phlebotominae) Under Experimental Conditions

ABSTRACT This no-choice, laboratory study focuses on the feeding of dried, ground, homogeneous powdered, unprocessed fruit and leaves of Azadirachta indica and Melia azedarach to Lutzomyia longipalpis larvae to determine the effects on their mortality and metamorphosis. A. indica and M. azedarach fruit and leaves significantly increased larval mortality in comparison to larvae fed the untreated, standard diet. A. indica fruit and leaves blocked the molting of the larvae to the fourth instar, resulting in them remaining as third instars until the end of the experiment. M. azedarach fruit also blocked the molting of larvae, which remained permanently in the fourth instar. Feeding M. azedarach leaves resulted in greater molt inhibition. All insects in this group stopped their development as second-instar larvae. No antifeedant effect was detected for any experimental treatment. The results indicate that nontoxic, unprocessed materials obtained from A. indica and M. azedarach are potent development inhibitors of L. longipalpis larvae.

Life cycle differences among Brazilian sandflies of the Lutzomyia longipalpis sibling species complex.

The developmental cycles of five Brazilian populations of the Lutzomyia longipalpis Lutz & Neiva species complex (Diptera: Psychodidae) were compared under laboratory conditions. Three of the populations were derived from insects collected in allopatric sites at Natal (Rio Grande do Norte State), Jacobina (Bahia State) and Lapinha Cave (Minas Gerais State). The other two originated from Sobral (Ceará State), where the males of two sympatric species can be distinguished by the presence of one (1S) or two (2S) pairs of abdominal spots. The results of the present study clearly show that all three populations whose males produce C16 pheromones and use pulse‐type copulation songs (Jacobina, Lapinha Cave and Sobral 1S) are more easily adapted to the colonization conditions used in our laboratory, producing larger egg batches, with higher survival and an overall faster developmental cycle. This contrasts with populations producing C20 male pheromones and using burst‐type copulation songs (Natal and Sobral 2S) that produce smaller egg batches, have higher oviposition mortality and a slower rate of development under identical laboratory conditions. In conclusion, these phenological differences are a further indication of the differentiation of the siblings within the Lu. longipalpis species complex.

Scanning electron microscopy of the egg of Haemagogus tropicalis.

ABSTRACT Haemagogus tropicalis is strictly a forest-dwelling species from the fertile valley area of the Amazônia forest. It is a diurnal mosquito, and the oviposition sites for the species include tree holes. The eggs of Hg. tropicalis used in this study were from females captured on Combú Island, situated across from the city of Belém, Guajará Bay, state of Pará, at 1°25′S latitude and 48°25′W longitude. The eggs are elliptical and ∼575 µm long with a width of ∼144 µm. The ventral surface of the chorionic reticulum has regular chorionic cells with hexagonal and sometimes pentagonal ornamentation. Each chorionic cell has a thick external chorionic reticulum with regular borders. The interior of the chorionic cells have small, evenly distributed tubercles, and the dorsal external chorionic reticulum appears porous. The micropylar apparatus, located on the anterior area of the egg, was formed by a collar with a well-developed frame. Centrally, the micropylar disc had a diameter of ∼20 µm and the micropylar orifice is 2.1 µm in diameter. These data may enable construction of taxonomic keys for identifying eggs of Haemagogus species.

In Vitro Inhibition of Leishmania Attachment to Sandfly Midguts and LL-5 Cells by Divalent Metal Chelators, Anti-gp63 and Phosphoglycans

Leishmania braziliensis and Leishmania infantum are the causative agents of cutaneous and visceral leishmaniasis, respectively. Several aspects of the vector-parasite interaction involving gp63 and phosphoglycans have been individually assayed in different studies. However, their role under the same experimental conditions was not studied yet. Here, the roles of divalent metal chelators, anti-gp63 antibodies and purified type I phosphoglycans (PGs) were evaluated during in vitro parasite attachment to the midgut of the vector. Parasites were treated with divalent metal chelators or anti-gp63 antibodies prior to the interaction with Lutzomyia longipalpis/Lutzomyia intermedia midguts or sand fly LL-5 cells. In vitro binding system was used to examine the role of PG and gp63 in parallel. Treatment with divalent metal chelators reduced Le. infantum adhesion to the Lu. longipalpis midguts. The most effective compound (Phen) inhibited the binding in both vectors. Similar results were observed in the interaction between both Leishmania species and the cell line LL-5. Finally, parallel experiments using anti-gp63-treated parasites and PG-incubated midguts demonstrated that both approaches substantially inhibited attachment in the natural parasite-vector pairs Le. infantum/Lu. longipalpis and Le. braziliensis/Lu. intermedia. Our results suggest that gp63 and/or PG are involved in parasite attachment to the midgut of these important vectors.

Estudo comparativo entre larvitrampas e ovitrampas para avaliação da presença de Aedes aegypti (Diptera: Culicidae) em Campo Grande, Estado do Rio de Janeiro

With the objective of evaluating the efficiency of traps for monitoring dengue and yellow fever vectors in Rio de Janeiro, 12 larvitraps and 12 ovitraps were used simultaneously for 13 weeks. The results indicated that the larvitraps presented greater capacity for positive findings, thereby highlighting it as an important monitoring tool for vector surveillance.

Studies on Phlebotominae (Diptera: Psychodidae) in the Campus FIOCRUZ Mata Atlântica, Jacarepaguá, in the City of Rio de Janeiro, Brazil

INTRODUCTION The presence of American cutaneous leishmaniasis (ACL) in the communities of the Campus FIOCRUZ Mata Atlântica (CFMA) in the City of Rio de Janeiro initiated the investigation of the Phlebotominae fauna in the Atlantic Forest to determine the occurrence of putative ACL vectors associated with the enzootic cycle. METHODS For 24 consecutive months, sand flies were captured inside the forest and in the border area near the communities. RESULTS The following sand fly species were identified: Brumptomyia brumpti, Brumptomyia cunhai, Brumptomyia nitzulescui, Lutzomyia edwardsi, Lutzomyia pelloni, and Lutzomyia quinquefer. Other identified sand fly vectors, such as Lutzomyia intermedia (the predominant species), Lutzomyia migonei, Lutzomyia whitmani, Lutzomyia fischeri, and Lutzomyia hirsuta hirsuta, are associated with ACL transmission, and the vector for American visceral leishmaniases (AVL), Lutzomyia longipalpis, was also found. CONCLUSIONS All sand fly vectors were found in both studied environments except for Lutzomyia whitmani, which was only identified in the forest. This study represents the first identification of Lutzomyia longipalpis in the CFMA, and the epidemiological implications are discussed.

Effects of Azadirachtin on the Biology of Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae) Adult Female, the Main Vector of American Visceral Leishmaniasis

ABSTRACT The effects of azadirachtin A added to the sucrose diet of the adult females on the mortality, oviposition, and hatching of the sand fly vector of American visceral leishmaniasis Lutzomyia longipalpis (Lutz & Neiva, 1912) were investigated. Concentrations of 0.1, 1.0, and 10.0 &mgr;g/mg of azadirachtin significantly increased insect mortality in comparison with control insects. The same dose also significantly reduced oviposition but not hatching. After a long development period, significantly fewer adult insects were obtained from eggs hatching by azadirachtin-treated females in a doseresponse manner. These results indicate that azadirachtin is a potent sterilizer that could be used against the development of Lu. longipalpis populations and as a tool for studying physiological and biochemical processes in phlebotomine species.

Structural study of the salivary glands of Anocentor nitens (Acari: Ixodidae) during the feeding cycle

The salivary glands of Anocentor nitens (Neumann, 1897 ) occur in pairs and are located in the anterolateral region of the general cavity, with milky white color and approximately equal sizes. They consist of a secretory portion and an excretion duct. In some glandular acini, all the cells had a basophilic appearance they were stained by hematoxylin, whereas others presented cells with different staining affinities. In this work, we describe the variations observed in these glands during the feeding cycle of ticks [after feeding (0 h) and successively at 24, 48, 72, 96, 120, and 144 h]. The cells stained by hematoxylin were shown to be more reactive to Alcian blue, thus demonstrating the presence of acid glycosaminoglycans, whereas those stained using eosin presented weak or no reaction. A strong reaction was found by the use of the periodic acid‐Schiff (PAS) technique, thereby suggesting the presence of glycogen and/or glycoconjugates containing hexose, confirmed by using salivary amylase before PAS, with partial destaining of the slides. Continuing presence of residual staining in these cells suggests the presence of glycoconjugates containing hexose. Cells with nuclei of circular outline and few granules (of different sizes) were found in type II acini, 72 h after collection. Type I acini presented wide lumina and walls composed of larger numbers of cells of cubic to cylindrical shape. The pronounced degranulation shown in this study over the course of the feeding cycle was associated with the release of substances for oviposition. Microsc. Res. Tech., 2009.