Artur Gomes Dias-Lima

Trapping Triatominae in Silvatic Habitats

Large-scale trials of a trapping system designed to collect silvatic Triatominae are reported. Live-baited adhesive traps were tested in various ecosystems and different triatomine habitats (arboreal and terrestrial). The trials were always successful, with a rate of positive habitats generally over 20% and reaching 48.4% for palm trees of the Amazon basin. Eleven species of Triatominae belonging to the three genera of public health importance (Triatoma, Rhodnius and Panstrongylus) were captured. This trapping system provides an effective way to detect the presence of triatomines in terrestrial and arboreal silvatic habitats and represents a promising tool for ecological studies. Various lines of research are contemplated to improve the performance of this trapping system.

Sylvatic vectors invading houses and the risk of emergence of cases of Chagas disease in Salvador, State of Bahia, Northeast Brazil

During the last twenty years, several adults of Triatoma tibiamaculata infected with Trypanosoma cruzi have been spontaneously caught by inhabitants, inside their houses in the new habitational district of Pitua¿u of Salvador, Bahia. In this communication the authors call attention to the necessity of studies about the possibility of occurrence of new human cases of Chagas disease, to clarify the obscure origin of some positive blood donors in Salvador.

Investigação de áreas de risco como metodologia complementar ao controle da leishmaniose visceral canina

Risk areas of canine visceral leishmaniasis in the city of Camacari, Bahia, Brazil, were investigated. A total of 278 dogs from 141 homes pertaining to 20 investigated risk areas was serologically screened (ELISA). The general seroprevalence was 21.7% (56/258) after exclusion of 20 dogs used at the beginning of the survey to limit the study area. The respective results of the univariated and multivariated analysis of factors related to infection of dogs by Leishmania chagasi, to vector distribu-tion pattern in the area and to the methodology used to localize the canine focuses are discussed.

Horizontal stratification of the sand fly fauna (Diptera: Psychodidae) in a transitional vegetation between caatinga and tropical rain forest, state of Bahia, Brazil

A study about the horizontal stratification of the sand fly fauna in two distinct ecosystems, caatinga area, endemic for visceral leishmaniasis, and the tropical rain forest area, endemic for cutaneous leishmaniasis, was performed in the state of Bahia, Brazil. Lutzomyia longipalpis was predominant in the caatinga, and following it came the species L. capixaba and L. oswaldoi. In the tropical rain forest other species were found, such as L. intermedia, L. migonei, L. whitmani, L. yuilli, L.fischeri, L. damascenoi, L. evandroi, L. monticola, and L. lenti. It was found that the geographical limits of the vector species of visceral and cutaneous leishmaniasis are clearly defined by the biological and phytogeographic characteristics.

Wild Habitat and Related Fauna of Panstrongylus lutzi (Reduviidae, Triatominae)

Abstract Although Panstrongylus lutzi (Neiva and Pinto) is currently the fifth most frequent species of Triatominae captured in artificial structures in Brazil, its silvatic habitat remains unknown. A survey of its natural ecotopes was performed in an area of Bahia State. P. lutzi nymphal instars and adults were detected in burrows of Dasypodidae. Silvatic habitat of four other endemic triatomine species of the caatinga (Triatoma pseudomaculata Correa and Espinola, Triatoma brasiliensis Neiva, Rhodnius neglectus Lent, and Psammolestes tertius Lent and Jurberg) was also recorded.

Estratificação vertical da fauna de flebótomos (Diptera, Psychodidae) numa floresta primária de terra firme da Amazônia Central, Estado do Amazonas, Brasil

Studies on the vertical stratification of phlebotomine sandfly fauna were conducted in a non-flooded primary forest at a Tropical Forest Experimental Station of the National Institute of Amazonian Research from October 1998 to March 1999. CDC light traps were placed at one, 10, and 20 meters above ground. A total of 2,859 sandflies were captured, belonging to the Lutzomyia (99.93%) and Brumtomyia (0.07%) genera, represented by 38 species. In the Lutzomyia gender, the most frequent sub-gender was Nyssomyia (43.4%), followed by Psychodopygus (22.8%). Lutzomyia umbratilis, L. anduzei, L. rorotaensis, L. trichopyga, and L. olmeca nociva predominated at one meter above ground, while L. davisi, L. infraspinosa, L. umbratilis, L. trichopyga, and L. anduzei predominated at 10 meters. L. anduzei, L. tuberculata, L. dendrophyla, and L. dreisbachi were the most abundant species at 20 meters. L. umbratilis, which appeared at all three levels of vertical stratification, has great epidemic significance as a vector of Leishmania (Viannia) guyanensis.

Resultados preliminares de um projeto sobre a ecologia dos flebotomineos vetores de leishmaniose tegumenar no estado da Bahia

Preliminary data of a project about the ecology of the Phlebotominae (sandflies) in a tegumentary leishmaniasis area of coconut plantation in the south of the State of Bahia, Brazil are presented. There are 60 dwellings far of one another, where existed 31 dogs and 229 inhabitants.Among them 41.5% were Montenegro positive; 37.5% from these had scars of healed ulcers and 8.8% had active ulcers. 53 % of the house had dogs from which 22 % were seropositive,from the 7dogs with ulcers only 3 were seropositive. 14% of the inspected house harboured sandflies inside them. During two years of observations 72 sentinels hamsters were maintened at houses of patients with leishmaniasis ulcers, but they did not get the infection. During two years of observation, monthly collectings of sandflies were made inside house, chicken pen, curral, tree trunks and open field around a house with a patient with leishmaniasis. Tlte following results were already obtained about the vectors: 5,614 specimens were identified as belonging to fourteen different species of sandflies. Among them Lutzomyia whitmani (92%) and Lutzomyia intermedia (4.8%) were the most abundant species. They are very anthropophilic and can be found inside houses and at peridomestic sites. Probably they are the principal vectors of the disease at domestic places. The other twelve species were less frequent and more found at sylvatic places in inspite they also bite the man. Generally the biting activity of most of the species of the area begins at 5 p.m. in the dusk and reaches its peak at 0 hour a. m. ,when begins declining untildisapear at 7 a.m. L. whitmani was similarly collected with the same density in all lunar phases while L. intermedia was more abundant during the new moon phase. Most of the hundreds sandflies collected during the second year of observations, remains preserved in liquid nitrogen, watching for the adjustment of PCR molecular techniques to be processed for determination of the vector natural infection rates with leishmanias. Final results on all the project will be published as soon as the examination of such material has been processed.

Behavioral Plasticity of Triatominae Related to Habitat Selection in Northeast Brazil

Abstract Triatoma pseudomaculata Corrêa and Espínola, 1964 and Triatoma juazeirensis Costa and Felix, 2007 (=T. brasiliensis Neiva, 1911 [part]), are sylvatic vectors of Trypanosoma cruzi (Chagas, 1909), the causative agent of Chagas disease, in northeast Brazil—especially in the caatinga region. In an area of caatinga in the State of Bahia, we compared the wild and peridomestic habitats of these two species of Triatominae to assess their behavioral plasticity in relation to habitat selection in different environments. In the sylvatic environment, the habitat of these two species is never shared. T. pseudomaculata is found in trees and bird nests, but without apparent preference for any particular tree species. In contrast, T. juazeirensis is exclusively rupicolous (found among rocks). Both species invade peridomestic structures but do not display a significant ability to colonize human dwellings. In the peridomestic area, they are highly adaptable to different habitats and can occupy substrates that they do not colonize in the sylvatic environment. This behavioral plasticity seems to be more striking in T. juazeirensis—rupicolous in sylvatic environments but colonizing wooden structures in the peridomicile in >80% of cases.

Vertical stratification of phlebotomine sandfly fauna (Diptera, Psychodidae) in a primary non-flooded forest of the Central Amazon, Amazonas State, Brazil

Studies on the vertical stratification of phlebotomine sandfly fauna were conducted in a non-flooded primary forest at a Tropical Forest Experimental Station of the National Institute of Amazonian Research from October 1998 to March 1999. CDC light traps were placed at one, 10, and 20 meters above ground. A total of 2,859 sandflies were captured, belonging to the Lutzomyia (99.93%) and Brumtomyia (0.07%) genera, represented by 38 species. In the Lutzomyia gender, the most frequent sub-gender was Nyssomyia (43.4%), followed by Psychodopygus (22.8%). Lutzomyia umbratilis, L. anduzei, L. rorotaensis, L. trichopyga, and L. olmeca nociva predominated at one meter above ground, while L. davisi, L. infraspinosa, L. umbratilis, L. trichopyga, and L. anduzei predominated at 10 meters. L. anduzei, L. tuberculata, L. dendrophyla, and L. dreisbachi were the most abundant species at 20 meters. L. umbratilis, which appeared at all three levels of vertical stratification, has great epidemic significance as a vector of Leishmania (Viannia) guyanensis.The aim of this study was to examine the effect of demographic, socioeconomic, environmental, maternal reproductive, dietary, and nutritional variables on diarrhea risk and prognosis using a hierarchical framework. A case-control study of children aged 0-23 months in Greater Metropolitan Porto Alegre was conducted during the peak season for diarrhea in 1987-1988. Three groups were investigated, with 192 children each. The first group included hospitalized children with an episode of acute diarrhea complicated by moderate to severe dehydration. The second group included children with acute mild diarrhea without signs of dehydration who were identified in the same neighborhood as hospitalized cases. The third group consisted of controls without diarrhea. Mothers were interviewed by trained interviewers using a standardized questionnaire. Data analysis included a hierarchical approach to control for confounding, using conditional logistic regression. Comparison of the three groups aimed to identify risk factors for diarrhea complicated by dehydration, prognostic factors for dehydration, and risk factors for mild diarrhea. Low birth weight, stunting, and lack or breastfeeding acted simultaneously as risk and prognostic factors for diarrhea.

Flebotomíneos (Díptera: Psychodidae) de uma Floresta Primária de Terra Firme da Estação Experimental de Silvicultura Tropical, Estado do Amazonas, Brasil

Studies about sand flies fauna were carried out in a non-flooded primary forest at the Experimental Station of Tropical Forest - National Institute of Amazon Research, between October 1998 and March 1999. CDC light traps were placed at 1m, 10m and 20 meters above ground level. 7.409 phlebotomines were collected, belonging to the genera, Lutzomyia (99,98%) and Brumptomyia (0,02%), represented by 39 species. In the genus Lutzomyia, the more frequent subgenus was Nyssomyia, with 39,43%, followed by Psychodopygus with 22,68%. The number of sandflies collected was increased, from the beginning of the rainy station.