Larvicidal, cytotoxic and genotoxic effects of aqueous leaf extract ofJatropha mollissima (Pohl) Baill / Efeitos larvicida, citotóxico e genotóxico do extrato aquoso das folhas de Jatrophamollissima (Pohl) Baill

The present study aimed to evaluate the larvicidal effect of aqueous leaf extract fromJatropha mollissima on the larvae of Aedes aegypti and analyze its cytotoxic and genotoxic activity in the Alliumcepa test. Larvae of the mosquito were exposed to the negative and positive controls (distilled water anddiflubenzuron, 0.003 mg mL-1, respectively) and to leaf extract concentrations of 0.001, 0.005, 0.01, 0.02,0.04, 0.06, 0.08 and 0.1 mg mL-1. The mortality rate was evaluated every 24 hours over five days. For thecytotoxic and genotoxic analyses, roots of A. cepa were exposed to the negative (distilled water) and positivecontrol (trifluralin, 0.84 ppm) and to different leaf extract concentrations (0.01, 0.1, 1 and 10 mg mL-1) for24 hours. The statistical analyses were performed by Kruskal-Wallis test (p < 0.05). The leaf extractpresented promising larvicidal activity at the concentrations of 0.08 and 0.1 mg mL-1, and none of theconcentrations evaluated in A. cepa exhibited cytotoxic or genotoxic effect. Since the larvicidal action of J.mollissima and the absence of cellular toxicity have been demonstrated, further studies are recommended todetermine the mechanism of action of the extract as a possible natural larvicide.

O presente estudo teve como objetivo avaliar o efeito larvicida do extrato aquoso das folhas deJatropha mollissima sobre as larvas de Aedes aegypti e analisar sua atividade citotóxica e genotóxica no testeAllium cepa. As larvas do mosquito foram expostas aos controles negativo e positivo (água destilada ediflubenzuron, 0,003 mg mL-1, respectivamente) e ao extrato foliar nas concentrações de 0,001; 0,005; 0,01;0,02; 0,04; 0,06; 0,08 e 0,1 mg mL-1. A taxa de mortalidade foi avaliada a cada 24horas durante cinco dias.Para as análises citotóxica e genotóxica, as raízes de A. cepa foram expostas ao controle negativo (águadestilada) e positivo (trifluralina, 0,84 ppm) e nas concentrações (0,01; 0,1; 1 e 10 mg mL-1) do extrato foliarpor 24 horas. Análises estatísticas foram realizadas pelo teste de Kruskal-Wallis (p < 0,05). O extrato foliarapresentou atividade larvicida promissora nas concentrações de 0,08 e 0,1 mg mL-1, e nenhuma dasconcentrações avaliadas em A. cepa exibiu efeito citotóxico ou genotóxico. Uma vez demonstrada a açãolarvicida de J. mollissima e a ausência de toxicidade celular, mais estudos são recomendados para determinaro mecanismo de ação do extrato como um possível larvicida natural.

Dinâmica das alterações do baço associadas ao estado clínico de cães com leishmaniose visceral / Dynamic of changes of the spleen associated with the clinical status ofdogs with visceral leishmaniasis

Foram avaliadas as alterações esplênicas de cães com leishmaniose visceral, sintomáticos e assintomáticos, em relação ao número de sinais clínicos observados nestes animais. Cães sintomáticos foram divididos em cinco grupos de acordo com o número de sinais clínicos presentes. Nos grupos com três ou mais sinais, houve hipertrofia e hiperplasia dos cordões esplênicos e depleção de células linfóides da bainha periarteriolar. No grupo de cães com apenas um sinal clínico houve depleção de folículos da polpa branca. Hiperplasia dos folículos foi observada em intensidade maior no grupo de cães mostrando mais de cinco sinais clínicos.Granulomas estavam presentes em maior intensidade no grupo de cães exibindo cinco sinais. Granulações eosinofílicas no citoplasma de células plasmáticas (corpúsculos de Russell) foram significativamente maiores no grupo de cães com cinco sinais clínicos em comparação com aqueles com apenas um, dois, três e quatro sinais clínicos e cães assintomáticos. Os resultados mostram que o baço apresenta profundas alterações morfológicas que podem influenciar a evolução da infecção.

Alterations in the spleen of dogs with symptomatic and asymptomatic leishmaniasis have been evaluated with respect to the number of clinical signs observed in such animals. Symptomatic dogs were divided into five groups according to the number of clinical signs presented. In groups with three or more signs, there was hypertrophy and hyperplasia of the splenic cords and depletion of periarteriolar lymphatic sheath cells. In the group of dog with only one clinical sign, a there was follicle depletion in the white pulp. Follicle hyperplasia was higher in the canine group showing more than five clinical signs. Granulomas were present in a greater quantity in the canine group exhibiting five signs. Eosinophil granulations in the cytoplasm of plasma cells (Russell bodies) were significantly greater in the canine group with five clinical manifestations compared to those with only one, two, three and four manifestations and to asymptomatic dogs. The results show that the spleen undergoes profound morphologic changes that can influence the outcome of infection.

Distribuição geográfica, infestação domiciliar e infecção natural de triatomíneos (Hemiptera: Reduviidae) no Estado do Piauí, Brasil, 2008 / Geographic distribution, domiciliary infestation and natural infection of triatomines (Hemiptera: Reduviidae) in Piauí State, Brazil, in 2008

Ações de controle e vigilância da doença de Chagas devem incluir dados ecológicos e geográficos de seus vetores. O objetivo deste estudo é analisar a distribuição geográfica, a infestação domiciliar e a infecção natural das espécies de triatomíneos capturadas no Estado do Piauí , Brasil. Os registros de ocorrência e indicadores entomológicos (espécimes capturados em intra e peridomicílio, infestação, colonização e infecção natural) das espécies de triatomíneos foram obtidos a partir de capturas domiciliares em 129 municípios do Piauí, em 2008. Das 11 espécies registradas, Triatoma brasiliensis e T. pseudomaculata apresentaram ampla distribuição geográfica, seguidas de Panstrongylus lutzi e T. sordida. Rhodnius neglectus ocorreu mais ao sul (em áreas de cerrado), enquanto R. nasutus, R. pictipes e R. robustus foram registradas em áreas ao norte do Estado. P. geniculatus, P. megistus e Psammolestes tertius ocorreram raramente. Dos 22.896 triatomíneos capturados, T. brasiliensis apresentou os maiores índices de infestação e colonização. O índice de infecção natural de triatomíneos por flagelados morfologicamente similares a Trypanosoma cruzi foi de 0,8 por cento. Após 30 anos de controle e vigilância de vetores da doença de Chagas no Piauí, observa-se a provável eliminação de T. infestans e a manutenção da magnitude de distribuição de T. brasiliensis e T. pseudomaculata. Nesse cenário, recomenda-se reforçar a vigilância entomológica e educação em saúde com intuito de reduzir as chances de colonização de triatomíneos nativos nas unidades domiciliares no Estado do Piauí.

The control and surveillance of Chagas disease must include ecological and geographical data on its vectors. The objective of this study is to analyze the geographic distribution, domiciliary infestation and natural infection patterns of triatomines captured in Piauí State, Brazil. Occurrence records and entomological data for the triatominae species, such as specimens captured in intra- and peridomiciliary locations and infestation, colonization, and natural infection data, were obtained via domiciliary capture in 129 municipalities in Piauí in 2008. Of the 11 recorded species, Triatoma brasiliensis and T. pseudomaculata presented the widest geographic distribution, followed by Panstrongylus lutzi and T. sordida. Rhodnius neglectus was more frequent in the south (cerrado areas), whereas R. nasutus, R. pictipes and R. robustus were found in northern areas of the State. P. geniculatus, P. megistus and Psammolestes tertius were rare. Of the 22,896 captured triatomine specimens, T. brasiliensis presented the highest rates of infestation and colonization. The index of natural infection of triatominae by flagellates morphologically similar to Trypanosoma cruzi was 0.8 per cent. After 30 years of control and surveillance of Chagas disease vectors in Piauí, T. infestans may have been eliminated, and maintenance of a wide distribution of T. brasiliensis and T. pseudomaculata has been shown. Under this scenario, it is recommended that entomological surveillance and health education be reinforced to reduce the chances of colonization by native triatomine insects in households in Piauí State.

The role of salivary and intestinal complement system inhibitors in the midgut protection of triatomines and mosquitoes.

Saliva of haematophagous arthropods contain biomolecules involved directly or indirectly with the haematophagy process, and among them are encountered some complement system inhibitors. The most obvious function for these inhibitors would be the protection of the midgut against injury by the complement. To investigate this hypothesis, Triatoma brasiliensis nymphs were forced to ingest human serum in conditions in which the protection of midgut by the inhibitors is bypassed. In these conditions, the anterior midgut epithelium was injured by the complement, causing cell death. Once some insects such as Aedes aegypti have no salivary inhibitors, we hypothesized the existence of intestinal inhibitors. The inhibitory activity was investigated in the intestine of A. aegypti as well as in the saliva and intestine of other three triatomine species (T. brasiliensis, T. infestans and Rhodnius prolixus) using an immunological method able to determine the level of deposition of some complement factors (C1q, C3b, or C4b) on the surface of complement activator molecules linked to microplates. This methodology permitted to identify which points along the activation phase of the complement cascade were inhibited. As expected, soluble contents of A. aegypti's intestine was capable to inhibit C3b deposition by the classical and alternative pathways. Saliva or soluble intestinal contents, obtained from triatomines were unable to inhibit C1q deposition by the classical pathway. C4b deposition by the classical pathway was inhibited by the intestinal contents from the three triatomines. On the other hand, only T. brasiliensis saliva inhibited C4b deposition. Both, saliva and intestinal contents from all triatomines were able to inhibit C3b deposition in the classical and alternative pathways. None of the material extracted from the intestinal cell membranes from the triatomines inhibited C3b deposition in the classical pathway. The existence of complement inhibitors may have important biological consequences which are discussed in detail.