Ana Cristina Brito

The potential attractant or repellent effects of different water types on oviposition in Aedes aegypti L. (Dipt., Culicidae)

Abstract:  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 LD50 of salt for A. aegypti larvae was around 13%.

Coumarin Derivatives from Esenbeckia grandiflora. and its Larvicidal Activity Against Aedes aegypti.

Abstract From a hexane fraction prepared from the roots of Esenbeckia grandiflora. Mart., effective against fourth instar larvae of Aedes aegypti. L. (LC50 108.23 ppm), eight coumarin derivatives [daphnetin 7-methyl-8-(3,3-dimethylallyl) ether, a mixture containing pimpinellin eight one of its photodimerization product, 5-senecioyl-xanthotoxin, 3-(1′,1′)-dimethylallylcolumbianetin, swietenocoumarin B, isopimpinellin, xanthotoxin, and 5-(1′-hydroxyisopentenyl)bergapten] were isolated in addition to sitosterol and sitostenone. The mixture containing pimpinellin and its photodimerization product was effective against fourth instar larvae (LC50 at 45.77 ppm), and a mixture of pimpinellin and swietenocoumarin B showed a LC50 value of 62.23 ppm. All isolated compounds were identified on the basis of the spectral data including 2D experiments. Furthermore, previously unreported spectral data for some compounds are given.

Lymphatic Filariasis in Brazilian Urban Area (Maceió, Alagoas)

A cross-sectional survey conducted among evening students was used to determine the prevalence of Wuchereria bancrofti infection in Maceió, capital of the State of Alagoas, northeast Brazil. A single thick-blood smear was used, being collected between 10 p.m. and 12 a.m. From a total of 29,551 students enrolled at evening elementary schools in the 33 city sectors, 16,569 (56.4%) were random selected for inclusion in the study. From those, 10,857 (65.5%) were interviewed and examined and 73 (0.7%) were found to have microfilaraemia. Autochthonous W. bancrofti carriers live in 10 of the 33 city sectors, suggesting a focal distribution. Moreover, 84% of infections were diagnosed among 29% of all students examined, inhabiting three contiguous sectors at the city central area, presenting infection rates up to 5.3%. Students living in city sectors with prevalence of microfilariae carriers greater than 1% were found to have a higher risk for infection when compared to students from the rest of the town [Relative Odds (RO) 12.8, 95% CI 6.7-25.1]. 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, 95% CI 1.1-2.9).

Situação atual da filariose bancroftiana na cidade de Maceió, estado de Alagoas, Brasil

Com o objetivo de determinar a prevalencia e a distribuicao da filariose linfatica bancroftiana na area urbana de Maceio, estado de Alagoas, assim como identificar os insetos vetores na regiao, foram realizados inqueritos hemoscopicos e entomologicos. Foram examinadas, pelo metodo da gota espessa, amostras de sangue de 10.450 escolares oriundos de diferentes regioes da cidade, sendo detectado 0,66% de individuos microfilaremicos por Wuchereria bancrofti. A parasitose tem distribuicao focal com 80% dos individuos com infeccao patente detectados em duas regioes vizinhas, cujas prevalencias atingiram 1,24% e 5,25%. Estudos paralelos feitos em amostras populacionais com individuos de diferentes faixas etarias mostraram prevalencias semelhantes as detectadas entre os escolares. No entanto, o exame dos familiares de individuos infectados pela W. bancrofti mostrou prevalencia seis vezes mais alta, sugerindo maior transmissao no intradomicilio. A percentagem de parasitados foi maior no grupo etario mais jovem (< 20 anos). Mosquitos Culex quinquefasciatus capturados nos bairros onde a parasitose foi detectada apresentavam taxas de infeccao natural de 0,28% ate 4,62%. Esses dados descrevem a ocorrencia da transmissao natural da filariose bancroftiana na area urbana de Maceio, Alagoas. Baseadas nesses dados, medidas de controle da filariose foram planejadas para conter sua expansao na regiao analisada.

Terpenóides e avaliação do potencial antimalárico, larvicida, anti-radicalar e anticolinesterásico de Pouteria venosa (Sapotaceae)

This work describes the isolation of four triterpenes (taraxerol, ursolic acid, 3b,19a,23-trihydroxyurs-12-en-28-oic acid and 2a,3a,19a,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 (4th 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 first time in this species and were identified on basis of the spectral data (IR and NMR, including APT, DEPT), as well as by comparison with literature data.

A comparison of two Brazilian populations of Culex quinquefasciatus (Say, 1823) from endemic and non-endemic areas to infection with Wuchereria bancrofti (Cobbold, 1877).

Culex quinquefasciatus is known to be an efficient insect host of Wuchereria bancrofti. In Brazil Cx. quinquefasciatus is widely distributed throughout the country and is often abundant in and around human habitations. In contrast, Bancroftian filariasis is limited to three foci in Brazil. Experiments were undertaken to compare the vector capacities of Cx. quinquefasciatus originating from Maceió (Alagoas), one of the endemic areas of W. bancrofti infection in Brazil, and Belo Horizonte (Minas Gerais), a non endemic area. Laboratory-reared Cx. quinquefasciatus were dissected 20 days after blood feeding on microfilaraemic patients. Survival rates and the number of infective larvae that developed did not differ in female mosquitoes of different origins. Thus both populations of Culex were susceptible to infection with W. bancrofti.

Filariose bancroftiana em áreas urbanas do Estado de Alagoas, nordeste do Brasil: estudo em população geral

In order to assess the present status of lymphatic filariasis in Alagoas State, Brazil, hemoscopic surveys were carried out in the human population of the three different physiographic regions of the State. Blood samples were collected by thick smear technique taken after 10:00 p.m. From a total of 101 cities of the State, 10 were randomly selected, Bancroftian filariasis was only found in Maceio, the capital of Alagoas State. In a cross-sectional survey conducted among the general population of 4 neighborhoods in the city, 10,973 individuals were examined, 226 were microfilaraemic with prevalence in the city neighborhoods ranging from 0 to 5.4%. Prevalence rates and microfilariae density were significantly higher in males. Among the examined inhabitants born out of Maceio, microfilariae carriers had lived a significantly longer time in endemic areas than the amicrofilaraemic subjects. Based on the data obtained in the present study, measures to avoid expansion of bancroftian filariasis in the region were established.In order to assess the present status of lymphatic filariasis in Alagoas State, Brazil, hemoscopic surveys were carried out in the human population of the three different physiographic regions of the State. Blood samples were collected by thick smear technique taken after 10:00 p.m. From a total of 101 cities of the State, 10 were randomly selected, Bancroftian filariasis was only found in Maceió, the capital of Alagoas State. In a cross-sectional survey conducted among the general population of 4 neighborhoods in the city, 10,973 individuals were examined, 226 were microfilaraemic with prevalence in the city neighborhoods ranging from 0 to 5.4%. Prevalence rates and microfilariae density were significantly higher in males. Among the examined inhabitants born out of Maceió, microfilariae carriers had lived a significantly longer time in endemic areas than the amicrofilaraemic subjects. Based on the data obtained in the present study, measures to avoid expansion of bancroftian filariasis in the region were established.

Prevalência da filariose canina causada por Dirofilaria immitis e Dipetalonema reconditum em Maceió, Alagoas, Brasil

A prevalencia da filariose canina causada por Dirofilaria immitis e Dipetalonema reconditum, foi estimada apos a realizacao de inquerito hemoscopico em 1.519 caes domiciliados. Foram examinados 1.097 caes nos sete distritos sanitarios da cidade de Maceio, Alagoas, 204 na Ilha de Santa Rita e 218 na cidade de Paripueira. Em Maceio, foram detectados 15 (1,3%) caes com microfilarias (MF) de D. immitis e 15 (1,3%) com MF de D. reconditum. Todos os casos positivos foram considerados autoctones. As MF de D. immitis e de D. reconditum mediram 298,1µm e 249,2µm de comprimento e 7,3µm e 4,4µm de largura, respectivamente. Alem do diagnostico parasitologico pela tecnica de gota espessa (100µL), foi utilizado o teste imunologico Witness, para deteccao de antigeno filarial circulante, o qual confirmou os dados parasitologicos e permitiu a deteccao de casos de infeccao oculta. De um total de 6.579 femeas examinadas, pertencentes a seis especies de mosquitos, oito (0,1%) femeas de Culex quinquefasciatus foram encontradas naturalmente infectadas com larvas de D. immitis. Estes resultados demonstram a presenca simultânea de D. immitis e D. reconditum na mesma area geografica.

The microfilarial periodicity of Wuchereria bancrofti in north-eastern Brazil.

The periodicity of Wuchereria bancrofti microfilariae (mff) in peripheral blood was analysed in 42 microfilaraemics living in Maceió, in Alagoas state, north-eastern Brazil. Nine blood samples were collected from each subject, over a 24-h period, and two quantitative (60-µl) thick smears were prepared from each sample. Although all the subjects had detectable microfilaraemias from 23.00 hours to 06.00 hours, no mff could be detected in most (71.4%) of the smears prepared from samples collected at 15.00 hours. Samples collected during the day, at 15.00 hours, contained 170 times fewer mff/µl than those collected at 01.00 hours, when microfilaraemias were generally most intense. For diagnosis of bancroftian filariasis in Maceió, blood samples should be collected between 22.00 and 03.00 hours, when microfilarial counts will be at least 90% of the peak counts. The circadian variation observed was independent of the subjects gender and microfilarial density. Mathematical analysis, using a simple harmonic-wave model, indicated a periodicity index of 127.6 and that maximum microfilarial densities occurred at 00.51 hours, confirming the nocturnal pattern of microfilaraemia in the study area.

Bancroftian filariasis in urban areas of Alagoas State, Northeast Brazil: study in general population

In order to assess the present status of lymphatic filariasis in Alagoas State, Brazil, hemoscopic surveys were carried out in the human population of the three different physiographic regions of the State. Blood samples were collected by thick smear technique taken after 10:00 p.m. From a total of 101 cities of the State, 10 were randomly selected, Bancroftian filariasis was only found in Maceio, the capital of Alagoas State. In a cross-sectional survey conducted among the general population of 4 neighborhoods in the city, 10,973 individuals were examined, 226 were microfilaraemic with prevalence in the city neighborhoods ranging from 0 to 5.4%. Prevalence rates and microfilariae density were significantly higher in males. Among the examined inhabitants born out of Maceio, microfilariae carriers had lived a significantly longer time in endemic areas than the amicrofilaraemic subjects. Based on the data obtained in the present study, measures to avoid expansion of bancroftian filariasis in the region were established.In order to assess the present status of lymphatic filariasis in Alagoas State, Brazil, hemoscopic surveys were carried out in the human population of the three different physiographic regions of the State. Blood samples were collected by thick smear technique taken after 10:00 p.m. From a total of 101 cities of the State, 10 were randomly selected, Bancroftian filariasis was only found in Maceió, the capital of Alagoas State. In a cross-sectional survey conducted among the general population of 4 neighborhoods in the city, 10,973 individuals were examined, 226 were microfilaraemic with prevalence in the city neighborhoods ranging from 0 to 5.4%. Prevalence rates and microfilariae density were significantly higher in males. Among the examined inhabitants born out of Maceió, microfilariae carriers had lived a significantly longer time in endemic areas than the amicrofilaraemic subjects. Based on the data obtained in the present study, measures to avoid expansion of bancroftian filariasis in the region were established.