RESUMO
The study of some of the behavioral aspects of the main vector of Leishmania infantum chagasi Cunha & Chagas in the Americas, Lutzomyia longipalpis (Lutz & Neiva), such as dispersion, population size, and vector survival rates, is important for the elucidation of the mechanisms of visceral leishmaniasis transmission. These parameters were studied by means of capture-mark-release-recapture experiments in an urban area of Campo Grande municipality, an endemic area of visceral leishmaniasis, situated in Mato Grosso do Sul state, Brazil. Six capture-mark-release-recapture experiments were undertaken between November 2009 and November 2010 and once in January 2012 with a view to assessing the population size and survival rate of Lu. longipalpis. The insects were released in a peridomicile surrounded by 13 residences. The recaptures were undertaken with automatic light traps for four consecutive weeks after release in the surrounding area. In total, 3,354 sand flies were captured, marked, and released. The overall recapture rate during the capture-mark-release-recapture experiments was 4.23%, of which 92.45% were recaptured at the release site, indicating limited dispersal. The greatest distance recorded from the release site was 165 m for males and 241 m for females. The male daily survival rate, calculated on the basis of regressions from the numbers of marked recaptured insects during the 15 successive days after release was 0.897. The estimated male population size measured by the Lincoln Index was 10,947.127. Though Lu. longipalpis presented a limited dispersion the physical barriers typical of urban environments did not prevent the sand flies from flying long distances.
Assuntos
Distribuição Animal , Insetos Vetores/fisiologia , Psychodidae/fisiologia , Animais , Brasil , Cidades , Feminino , Insetos Vetores/parasitologia , Leishmania/fisiologia , Leishmaniose Visceral/transmissão , Masculino , Densidade Demográfica , Psychodidae/parasitologia , Estações do Ano , Fatores de TempoRESUMO
Improving vector control remains a key goal in reducing the world's burden of infectious diseases. More cost-effective approaches to vector control are urgently needed, particularly because vaccines are unavailable and treatment is prohibitively expensive. The causative agent of American visceral leishmaniasis (AVL), Leishmania chagasi, Cunha and Chagas (Kinetoplastida: Trypanosomatidae), is transmitted between animal and human hosts by blood-feeding female sand flies attracted to mating aggregations formed on or above host animals by male-produced sex pheromones. Our results show the potential of using synthetic pheromones to control populations of Lutzomyia longipalpis Lutz and Neiva (Diptera: Psychodidae), the sand fly vector of one of the world's most important neglected diseases, AVL. We showed that a synthetic pheromone, (+/-)-9-methylgermacrene-B, produced from a low-cost plant intermediate, attracted females in the laboratory. By formulating dispensers that released this pheromone at a rate similar to that released by aggregating males, we were able to attract flies of both sexes to traps in the field. These dispensers worked equally well when deployed with mechanical light traps and inexpensive sticky traps. If deployed effectively, pheromone-based traps could be used to decrease AVL transmission rates through specific targeting and reduction of L. longipalpis populations. This is the first study to show attraction of a human disease-transmitting insect to a synthetic pheromone in the field, showing the general applicability of this novel approach for developing new tools for use in vector control.
Assuntos
Comportamento Animal/efeitos dos fármacos , Controle de Insetos/métodos , Insetos Vetores/efeitos dos fármacos , Leishmaniose/prevenção & controle , Psychodidae/efeitos dos fármacos , Sesquiterpenos de Germacrano/farmacologia , Atrativos Sexuais/farmacologia , Animais , Insetos Vetores/parasitologia , Psychodidae/parasitologiaRESUMO
We have examined the heparin binding proteins from Leishmania (Viannia) braziliensis promastigotes (HBP-Lb) by chromatography assays. The proposed strategy to isolate an enriched fraction of the HBP-Lb consisted of an association of the Triton X-114 method with affinity chromatography in heparin-Sepharose 4B column. SDS-PAGE analysis of the eluted proteins showed two main protein bands (65.0 and 54.5 kDa), while a single protein band was observed in native electrophoresis gel. The hemagglutination property of HBP-Lb over rabbit erythrocytes was confirmed up to 6.3+/-0.5 microg of protein mL(-1). Additionally, we have assayed the potential of HBP-Lb labeled with sulfo-NHS-LC-biotin in binding to nitrocellulose-immobilized gut proteins extracted of Lutzomyia intermedia and Lutzomyia whitmani. The results indicated a similar profile of five ligands (67.0, 62.1, 59.5, 56.0 and 47.5 kDa) in both studied Lutzomyia species. This is the first direct description of this class of protein in L. (V.) braziliensis with a suggestion of its biological activity in the interaction of Leishmania with Lutzomyia gut cells, which maybe a crucial step during this parasite's life cycle.
Assuntos
Moléculas de Adesão Celular/metabolismo , Leishmania braziliensis/metabolismo , Proteínas de Protozoários/metabolismo , AnimaisRESUMO
Leishmania spp. are distributed throughout the world, and different species are associated with varying degrees of disease severity. In Brazil, Leishmania transmission involves several species of phlebotomine sand flies that are closely associated with different parasites and reservoirs, and thereby giving rise to different transmission cycles. Infection occurs during the bloodmeals of sand flies obtained from a variety of wild and domestic animals, and sometimes from humans. The present study focused on detection of Leishmania DNA in phlebotomine sand flies from a cave in the state of Minas Gerais. Detection of Leishmania in female sand flies was performed with ITS1 PCR-RFLP (internal transcribed spacer 1) using HaeIII enzyme and genetic sequencing for SSUrRNA target. The survey of Leishmania DNA was carried out on 232 pools and the parasite DNA was detected in four: one pool of Lutzomyia cavernicola (Costa Lima, 1932), infected with Le. infantum (ITS1 PCR-RFLP), two pools of Evandromyia sallesi (Galvão & Coutinho, 1939), both infected with Leishmania braziliensis complex (SSUrRNA genetic sequencing analysis), and one pool of Sciopemyia sordellii (Shannon & Del Ponte, 1927), infected with subgenus Leishmania (SSUrRNA genetic sequencing analysis). The present study identified the species for Leishmania DNA detected in four pools of sand flies, all of which were captured inside the cave. These results represent the first molecular detection of Lu cavernicola with Le infantum DNA, Sc sordellii with subgenus Leishmania DNA, and Ev sallesi with Leishmania braziliensis complex DNA. The infection rate in females captured for this study was 0.17%.
Assuntos
Leishmania/isolamento & purificação , Psychodidae/parasitologia , Animais , Brasil , Cavernas , DNA de Protozoário/genética , DNA Espaçador Ribossômico/genética , Feminino , Leishmania/genética , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Análise de Sequência de DNA , Especificidade da EspécieRESUMO
Canine leishmaniasis caused by Leishmania chagasi (L. infantum) is found throughout the South American continent, including Brazil, and dogs are considered to be the main reservoir host for this parasite. To support the implementation of a diagnostic protocol for surveillance of the disease in the region of Belo Horizonte (Minas Gerais, Brazil) we have compared the sensitivity and specificity of two serological tests, indirect immunofluorescent antibody test (IFAT) and direct agglutination test (DAT), with the combination of direct microscopy-culture-PCR as the gold standard, using samples obtained from 103 dogs in the city of Belo Horizonte, Minas Gerais. The currently used standard serodiagnostic test, IFAT, had a sensitivity of 100% and its specificity was 74% compared to the gold standard of the study. The sensitivity and specificity of the DAT were 100% and 91%, respectively. On the basis of this study it is recommended to change from the IFAT to DAT for the serodiagnosis of canine leishmaniasis because of the superior specificity of the test combined with its user-friendliness.
Assuntos
Testes de Aglutinação/veterinária , Doenças do Cão/diagnóstico , Técnica Indireta de Fluorescência para Anticorpo/veterinária , Leishmaniose Visceral/veterinária , Reação em Cadeia da Polimerase/veterinária , Testes Sorológicos/veterinária , Testes de Aglutinação/métodos , Animais , Brasil , DNA de Protozoário/química , Diagnóstico Diferencial , Reservatórios de Doenças/veterinária , Doenças do Cão/epidemiologia , Cães , Técnica Indireta de Fluorescência para Anticorpo/métodos , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/epidemiologia , Reação em Cadeia da Polimerase/métodos , Sensibilidade e Especificidade , Estudos Soroepidemiológicos , Testes Sorológicos/métodosRESUMO
Immunological, parasitological, and molecular techniques were applied to blood samples of dogs to diagnose Leishmania infections. In 1997, 644 domestic dogs were studied. Peripheral blood samples were collected for serological diagnosis and detection of Leishmania parasite by polymerase chain reaction (PCR). The indirect immunofluorescence test was positive in 139 (21.6%) of 644 dogs examined. The PCR was performed in 70 blood samples and 3 bone marrow aspirates. A 120-bp fragment specific for Leishmania was present in PCR hybridization analysis of all seropositive samples in the molecular assays. The PCR hybridization test, which used a minicircle of Leishmania chagasi as a probe, was negative in 20 seronegative dogs. These results suggest that a combined PCR-Southern hybridization technique is a highly sensitive approach to diagnose leishmaniasis in dogs, which are a zoonotic reservoir of leishmaniasis for humans.
Assuntos
DNA de Protozoário/genética , Doenças do Cão/diagnóstico , Leishmania/isolamento & purificação , Leishmaniose Visceral/veterinária , Animais , Southern Blotting/veterinária , Medula Óssea/parasitologia , Brasil/epidemiologia , Primers do DNA , DNA de Protozoário/sangue , Doenças do Cão/epidemiologia , Cães , Leishmaniose Visceral/diagnóstico , Reação em Cadeia da Polimerase/veterinária , Valor Preditivo dos Testes , Sensibilidade e EspecificidadeRESUMO
We detected an outbreak of American cutaneous leishmaniasis in the Jequitinhonha River Valley, Minas Gerais, Brazil. Clinical and epidemiological aspects were studied for a period of two years. Data include results of physical examinations, Montenegro skin test and serology. In total 72 of the 299 individuals evaluated presented active lesions. Only one case out of these 72 patients showed the mucosal form of the disease. The precarious sanitary conditions, low educational level and low income found in the population studied demonstrated that, as with the other parasitic diseases, cutaneous leishmaniasis occurs with greater frequency in needy populations. A canine serological survey detected 20.3% (30/148) of dogs reactive to the Leishmania antigen. Lutzomyia intermedia was the predominant phlebotomine species and the majority of the specimens (84.9%) were captured in the peridomicile. Four samples from human and three from canine cases were isolated and characterised by PCR and isoenzymes as being Leishmania (Viannia) braziliensis. The peridomiciliary nature of the disease is discussed.
Assuntos
Surtos de Doenças , Leishmania braziliensis/isolamento & purificação , Leishmaniose Cutânea/epidemiologia , Pobreza , Adolescente , Adulto , Idoso , Animais , Brasil/epidemiologia , Criança , Pré-Escolar , Cães , Feminino , Humanos , Lactente , Leishmaniose Cutânea/diagnóstico , Masculino , Pessoa de Meia-IdadeRESUMO
Lutzomyia longipalpis (Lutz and Neiva) is a species complex of Lutzomyia pseudolongipalpis (Arrivillaga and Feliciangeli) and at least three other as yet undefined siblings. Isozyme and mitochondrial studies of allopatric populations across Central and South America have suggested the presence of four "clades" that have been hypothesized to have arisen mainly because of geographical isolation mechanisms. Parallel studies of sexual behavior as well as cross-mating and genetic analysis, of both allopatric and sympatric populations, suggest at least four sibling species that do not seem to correspond to the defined four "clades." In an effort to understand this apparent discrepancy, sympatric populations of L. longipalpis from a single South American country, Brazil, are being studied. In Brazil, three putative species can be identified by their male-produced sex pheromones: (S)-9-methylgermacrene-B, 3-methyl-a-himachalene, and a cembrene. We report here that analysis by coupled gas chromatography-mass spectrometry shows that L. longipalpis from Jaibas, Minas Gerais State, Brazil, occurs as two sympatric sex pheromone chemotypes. One chemotype is the cembrene type previously recorded in a L. longipalpis population from Sobral, Ceará State, Brazil, and the other is a new cembrene isomer not previously observed in L. longipalpis. The finding of this new chemotype strongly suggests that the L. longipalpis species complex in Brazil consists of four members rather than the three previously recognized and confirms previous analysis of genetic variation that had suggested the presence of a complex in Brazil.
Assuntos
Psychodidae/classificação , Animais , Brasil , Cruzamentos Genéticos , Meio Ambiente , Feminino , Geografia , Masculino , Psychodidae/fisiologia , Atrativos Sexuais/fisiologia , Comportamento Sexual AnimalRESUMO
Sensilla on the male terminalia of four different species of sand flies (Diptera: Psychodidae) are described. Two species belonged to the same species complex: Lutzomyia longipalpis (Lutz & Neiva) and L. cruzi (Mangabeira). Other Brazilian species complex was represented by L. lenti (Mangabeira) and L. carmelinoi (Ryan, Fraiha, Lainson & Shaw). Approximately 5-15 sensilla were found on the initial part of the styles of all species. Structurally, the sensory organs were similar to small coeloconica sensilla. Their number varied both individually and interspecifically. These sensilla may play an important role in the copulation behavior of these species of sand flies.
Assuntos
Psychodidae/ultraestrutura , Animais , MasculinoRESUMO
A morphometric survey examined adult specimens of Lutzomyia whitmani (Antunes & Coutinho) captured at 5 municipalities in southeastern and northeastern Brazil to compare the populations. The localities were Ilhéus (Bahia), Martinho Campos (Minas Gerais), Corte de Pedra (Bahia), Baturité (Ceará), and Amaraji (Pernambuco): all are known foci of American cutaneous leishmaniasis. Fifteen males and 15 females from each population were analyzed morphometrically for 42 and 37 characters, respectively. Statistical data alone were insufficient to discriminate among the 5 populations. Further analysis generated phenograms that indicated there were 2 spatial clusters: the 1st was composed of specimens from Ilhéus (Bahia) and Baturité (Ceará) and the 2nd of specimens from Martinho Campos (Minas Gerais), Corte de Pedra (Bahia), and Amaraji (Pernambuco). Although insufficient to define the taxonomic status of the populations studied, the results delineated the existence of biogeographical structuring within L. whitmani. Complementary studies on the susceptibility to Leishmania braziliensis infection in the 5 populations are in progress to clarify the relationship between the 2 biogeographical clusters and American cutaneous leishmaniasis transmission in those Brazilian regions.
Assuntos
Filogenia , Psychodidae/anatomia & histologia , Psychodidae/genética , Animais , Brasil , Feminino , Variação Genética , Geografia , Masculino , Psychodidae/classificaçãoRESUMO
During studies on the biology of sandflies in Itaipu, Rio de Janeiro state day catches were performed in a chicken house. Species such Lutzomyia intermedia, L. migonei and L. fischeri use the chicken house as refuge for blood digestion before moving for a better place to lay eggs. There is no evidence that chicken coop is a breeding site for those sandflies in the area.
Assuntos
Reservatórios de Doenças , Abrigo para Animais , Psychodidae , Animais , Comportamento Animal , Brasil , Galinhas , Feminino , Insetos Vetores , Leishmania , Leishmaniose/transmissãoRESUMO
Eighteen species of sand fly were collected from Amapá Sate, Brazil, with Centers for Disease Control light traps during May 1998. Five species (Lutzomyia aragaoi, L. inpai, L. brachipyga, L. inflata, and L. richardwardi) represent new records for the Amapá.
Assuntos
Insetos Vetores , Psychodidae , Animais , Brasil , Ecossistema , Dinâmica PopulacionalRESUMO
The present paper reports the experimental treatment of hamsters infected with Leishmania chagasi and Leishmania amazonensis with sodium stibogluconate (20 mg/kg/day x 20 days). Only with L. chagasi did the treatment result in the complete elimination of parasites from the spleen. However, no parasitological cure was achieved in hamsters infected with L. amazonensis.
Assuntos
Gluconato de Antimônio e Sódio/uso terapêutico , Antiprotozoários/uso terapêutico , Leishmania infantum , Leishmania mexicana , Leishmaniose Cutânea/tratamento farmacológico , Leishmaniose Visceral/tratamento farmacológico , Animais , Cricetinae , Avaliação Pré-Clínica de Medicamentos , Masculino , Mesocricetus , Fatores de TempoRESUMO
Between 1997-1998, the authors carried out sporadic collection of sand flies in the municipalities of Paraíso de Tocantins, Monte do Carmo, Porto Nacional and Monte Santo all in the Tocantins State of northern Brazil. Human bait was used in Monte Santo and a battery operated light trap in other municipalities. The ecotypes chosen for the traps were in the peridomiciles, inside the houses, in the forest and the orchard. We identified 2,677 sand flies, belonging to 32 species. The most abundant species of sand flies were Lutzomyia whitmani, Lutzomyia longipalpis, Lutzomyia carmelinoi, Lutzomyia evandroi, Lutzomyia longipennis and Lutzomyia antunesi. Collections from the forest showed greater diversity of species, while the largest number of sand flies were caught around the houses. Several species known or suspected to be vectors of Leishmania in other regions of Brazil were captured.
Assuntos
Phlebotomus , Animais , Brasil , Densidade DemográficaRESUMO
We dissected the digestive tract of 245 females in pools of 35 flies forming 7 groups. These flies were Lutzomyia longipalpis originating from Lapinha Cave, Lagoa Santa, Minas Gerais. Out of the 8 species of bacteria isolated there was a predominancy of Gram negative bacterias (GNB) in the group of non-fermenters of sugar belonging to the following species: Acinetobacter lwoffii, Stenotrophomonas maltophilia, Pseudomonas putida and Flavimonas orizihabitans. The group of GNB fermenters were: Enterobacter cloacae and Klebsiella ozaenae. In the Gram positive group we isolated the genera Bacillus thuringiensis and Staphylococcus spp.
Assuntos
Psychodidae/microbiologia , Animais , Brasil , PrevalênciaRESUMO
A description is given of male sandfly found in a piece of amber from Dominican Republic that dates from the Miocene period (20-15 m.y.a). It is assigned to the genus Trichopygomyia Barreto. The position of the spines on the style and the shape of the dorsal lobes of the paramere separate this fly from other species of the genus: it is here named Trichopygomyia killickorum sp. n.
Assuntos
Âmbar , Fósseis , Psychodidae/anatomia & histologia , Psychodidae/classificação , Animais , República Dominicana , Masculino , FilogeniaRESUMO
There are very few reports on the microbiota of the digestive tract of sand flies, an important omission considering that blood is not the only meal ingested. Male and female sand flies obtain sugar meals from several sources, thereby increasing their chance of infection with microorganisms. Chances of contamination are higher when insects are bred in the laboratory, and this may affect the development of Leishmania spp. From the digestive tract of 300 sand fly females separated in two groups we isolated 10 species of bacteria in group 1 and 8 species in group 2. In group 1, Enterobacteriaceae of the following genera were identified: Serratia, Enterobacter, and Yokenella and the non-fermenters: Pseudomonas, Acinetobacter, and Stenotrophomonas. In group 2, the Enterobacteriaceae Enterobacter and Serratia were identified as well as the non-fermenters Acinetobacter, Stenotrophomonas, Burkolderia, and Pseudomonas.
Assuntos
Sistema Digestório/microbiologia , Túbulos de Malpighi/microbiologia , Psychodidae/microbiologia , Animais , Sangue , Carboidratos , Feminino , AlimentosRESUMO
This is a report of the first finding of visceral leishmaniasis' vector Lutzomyia longipalpis in the urban area of Campo Grande, State of Mato Grosso do Sul. The importance of this finding regarding the transmission of the disease in this area is discussed.
Assuntos
Insetos Vetores , Leishmaniose Visceral/transmissão , Psychodidae , Animais , Brasil , Feminino , MasculinoRESUMO
Canine visceral leishmaniosis (CVL) may be an important factor preceding human outbreaks of the disease. We report that the prevalence of canine visceral leishmaniosis infection has been increasing in recent years in Anastácio town, located in the central western region of Brazil. Serological investigations showed that 75.3% of dogs presented antibody titres ranging from 1/40 to 1/160 in the indirect immunofluorescence antibody test (IFAT). Bone marrow and lymph node aspirates provided positive cultures and furnished parasites for enzymological and serological typing in 42.5% and 41.1% of the cases, respectively. All the strains were typed as Leishmania (L.) chagasi. This is primarily a canine disease that spills over into the human population as a zoonosis. The study showed the epidemiological features of the infection in a region in which the problem of visceral leishmaniosis has been underestimated.