The selection of oviposition sites by the yellow-fever mosquito, Aedes aegypti, was studied in the laboratory. The repellent or attractant effects of salinity and the presence of bacteria in water collected from a local community on the Brazilian coast were investigated. Water contaminated with bacteria (waste water and lagoon water) elicited significantly more oviposition than distilled water. Oviposition decreased with an increase in salinity, with almost no oviposition above 12%. The salinity tolerance of A. aegypti larvae was investigated by measuring their mortality in response to salt concentrations ranging from 10 to 15%. The LD 50 of salt for A. aegypti larvae was around 13%.

[Relative Odds (RO) 12.8,. Eleven positive individuals from non endemic areas were living in Maceió for more than 10 years; time of residence in the area was a major risk factor for infection among students not born in the region (p<0.01). Regarding sex, male students presented a higher proportion of positive (RO 1.7,).

RESUMO:O presente trabalho descreve o isolamento de quatro triterpenos (taraxerol, ácido ursólico, ácido 3β,19α,23-triidroxiurs-12-en-28-óico e ácido 2α,3α,19α,23-tetraidroxiurs-12-en-28-óico) e um fi toesteróide (espinasterol), bem como a avaliação do potencial antimalárico (cepa NK-65 do Plasmodium berghei), larvicida (larvas do 4º instar do Aedes aegypti), anti-radicalar (2,2-difenil-1-picril-hidrazila, DPPH) e anticolinesterásico de extratos das folhas, cascas do caule e caule de Pouteria venosa (Mart.) Baehni. Todos os compostos isolados estão sendo descritos pela primeira vez nesta espécie e foram identifi cados com base na análise de dados espectrais (IV e RMN, incluindo APT e DEPT), bem como pela comparação com dados descritos na literatura.Unitermos: Pouteria venosa, terpenóides, anticolinesterase, anti-radicalar, malária, larvicida.ABSTRACT: "Terpenoids and evaluation of the antimalarial, larvicidal, anti-radicalar and anticholinesterase potential of Pouteria venosa (Sapotaceae)". This work describes the isolation of four triterpenes (taraxerol, ursolic acid, 3β,19α,23-trihydroxyurs-12-en-28-oic acid and 2α,3α,19α,23-tetrahydroxyurs-12-en-28-oic acid) and a phytosteroid (spinasterol), as well as a preliminary evaluation of antimalarial (NK-65 strains of Plasmodium berghei), larvicidal (4 th instar of Aedes aegypti), anti-radicalar (2,2-diphenyl-1-pycryl-hydrazyl, DPPH) and anticholinesterase activities of Pouteria venosa (Mart.) Baehni extracts from leaves, stem barks and stems. All isolated compounds are being described for the fi rst time in this species and were identifi ed on basis of the spectral data (IR and NMR, including APT, DEPT), as well as by comparison with literature data

Culex quinquefasciatus is known to be an efficient insect host of

Dirofilaria immitis (Leidy, 1856) is a nematode that can be transmitted mainly by mosquitoes of the genera Aedes, Culex and Anopheles (KW Ludlam et al. 1970 JAVMA 157: 1354-1359. The susceptibility of mosquitoes to support development of D. immitis not only differs according to the vector species but also with regard to strains of a particular species (BM Christensen et al. 1984 J Invertebr Pathol 44: 267-274, CSB Apperson et al. 1989 Both mosquitos populations were originated from Maceió. Therefore, Ae. aegypti were reared at the insectary of Fiocruz, Recife, PE and the strain of Cx. quinquefasciatus was maintained at the insectary of the Universidade Federal de Alagoas in Maceió. Mosquitoes eggs were hatched in cubes containing dechlorinated water, larvae were reared with cat food (Whiskas ® ) and adults were kept at 27±1ºC and 70±10% R.H. A 4 years-old mixedbreed male dog naturally infected with D. immitis was used as the microfilariae (mf) donor (80 mf/ 20 µl blood) and one uninfected animal was used as control. Females 3-to 7-day-old of both mosquito species were allowed to feed on blood with anticoagulant via an artificial apparatus (LC Rutledge et al. 1964 Mosq News 24: 407-419) or directly on microfilaraemic and amicrofilaraemic dogs. Four different experiments were carried out and both mosquito species were fed simultaneously on the dog and via artificial apparatus between 4 p.m. and 5 p.m., during 30 min. Mosquitoes were dissected daily and D. immitis larvae were recorded. The developmental stages of the parasite were identified according to AER Taylor (1960 J Helminthol 34: 27-39). Mortality was recorded daily and the vector efficiency of mosquito species was determined as described by L Kartman (1954 Exp Parasitol 2: 27-78).Survival rates recorded with a total of 1,573 Cx. quinquefasciatus and 1,588 Ae. aegypti females fed on the microfilaraemic dog, were 30.6% and 20% respectively. For mosquitoes fed on the uninfected dog the values were 85% for the former and 46.4% for the latter species. The death of infected mosquitoes could be caused by the movement of large numbers of mf from the midgut to the Malpighian tubules as suggested by DR Hamilton and RE Bradley (1979 J Med Entomol 3: 305-306). The sausage form was observed on the 4th day and from days 8 to 9, the larvae grew longer and more narrow (L 2 ) reaching the infective larval stage (L 3 ) on the 10th day for Ae. aegypti and four days later for Cx. quinquefasciatus. Shorter developmental periods of D. immitis in a vector, as observed in Ae. aegypti, would favour disease transmission (KM Loftin et al. 1995 J Am Mosq Control Assoc 11: 90-93). Although both mosquito species ingested similar number of mf, the number of L 3 recorded per female was significantly higher in Ae. aegypti. In fact, no L 3 were recorded in Cx. quinquefasciatus which fed directly on the microfilaraemic dog and only one L 3 + Corresponding