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Different Host Complement Systems and Their Interactions with Saliva from Lutzomyia longipalpis (Diptera, Psychodidae) and Leishmania infantum Promastigotes  [PDF]
Antonio Ferreira Mendes-Sousa, Alexandre Alves Sousa Nascimento, Daniel Costa Queiroz, Vladimir Fazito Vale, Ricardo Toshio Fujiwara, Ricardo Nascimento Araújo, Marcos Horácio Pereira, Nelder Figueiredo Gontijo
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0079787
Abstract: Background Lutzomyia longipalpis is the vector of Leishmania infantum in the New World, and its saliva inhibits classical and alternative human complement system pathways. This inhibition is important in protecting the insect′s midgut from damage by the complement. L. longipalpis is a promiscuous blood feeder and must be protected against its host’s complement. The objective of this study was to investigate the action of salivary complement inhibitors on the sera of different host species, such as dogs, guinea pigs, rats and chickens, at a pH of 7.4 (normal blood pH) and 8.15 (the midgut pH immediately after a blood meal). We also investigated the role of the chicken complement system in Leishmania clearance in the presence and absence of vector saliva. Results The saliva was capable of inhibiting classical pathways in dogs, guinea pigs and rats at both pHs. The alternative pathway was not inhibited except in dogs at a pH of 8.15. The chicken classical pathway was inhibited only by high concentrations of saliva and it was better inhibited by the midgut contents of sand flies. Neither the saliva nor the midgut contents had any effect on the avian alternative pathway. Fowl sera killed L. infantum promastigotes, even at a low concentration (2%), and the addition of L. longipalpis saliva did not protect the parasites. The high body temperature of chickens (40°C) had no effect on Leishmania viability during our assays. Conclusion Salivary inhibitors act in a species-specific manner. It is important to determine their effects in the natural hosts of Leishmania infantum because they act on canid and rodent complements but not on chickens (which do not harbour the parasite). Moreover, we concluded that the avian complement system is the probable mechanism through which chickens eliminate Leishmania and that their high body temperature does not influence this parasite.
First record of Lutzomyia evansi (Nu?ez-Tovar 1924) in Mexico (Diptera: Psychodidae, Phlebotominae)
Ibá?ez-Bernal, Sergio;Rodríguez-Domínguez, Gabriela;Gómez-Hernández, Carlos Hugo;Ricardez-Esquinca, Jorge R;
Memórias do Instituto Oswaldo Cruz , 2004, DOI: 10.1590/S0074-02762004000200002
Abstract: the phlebotomine sand fly lutzomyia evansi is recorded in mexico for the first time. this species is a suspected vector of leishmania infantum in other parts of its geographical range and was captured in a focus of american visceral leishmaniasis where the principal vector, lu. longipalpis sensu lato, was also found. the relative public health importance of the two species in the study area (chiapas state, southern mexico) is discussed.
Genetic analysis of a recently detected urban population of Lutzomyia evansi (Diptera: Psychodidae)in Colombia
Bejarano,Eduar Elías; Rojas,Winston; Uribe,Sandra; Vélez,Iván Darío; Porter,Charles H.;
Revista de la Sociedad Entomol?3gica Argentina , 2009,
Abstract: lutzomyia evansi (nú?ez-tovar) is the vector of the parasite leishmania infantum in rural zones of northern colombia. an attempt was made to determine the origin of a recently detected urban population of lutzomyia evansi by genetically characterizing specimens from seven geographically distinct localities in the colombian caribbean. insect specimens were collected in rural and urban environments of areas endemic for visceral leishmaniasis or free of the disease. nine polymorphic sites, nine nucleotide haplotypes and a single aminoacid haplotype were found within the 315 bp fragment sequenced, corresponding to the 3' end of the cytochrome b mitochondrial gene. paired genetic distances between the haplotypes, estimated with the kimura two-parameters model, varied from 0,0032-0,0194. analysis revealed low genetic variability between specimens from urban and rural localities. several of the sand flies collected in the city of sincelejo (department of sucre), where autochthonous visceral leishmaniasis cases have appeared in recent years, were genetically similar to those of a rural focus of the disease (el contento, on the neighboring department of córdoba). the epidemiological implications of this finding for leishmania infantum transmission in the colombian caribbean are discussed.
Variabilidad genética en Lutzomyia ( verrucarum) evansi (Nú ez-Tovar, 1924), vector de Leishmaniosis visceral americana
Eduar E. Bejarano,Winston Rojas,Sandra Uribe,Iván D. Vélez
Iatreia , 2001,
Abstract: Lutzomyia evansi (Nú ez-Tovar, 1924), Lutzomyia longipalpis (Lutz y Neiva, 1912) y Lutzomyia cruzi (Mangabeira, 1938), son los vectores de Leishmania infantum Nicolle, 1908, en el neotrópico. Lu. evansi ha sido incriminada como vector en zonas rurales de la Costa Caribe Colombiana, y algunas zonas de Venezuela y Nicaragua. A pesar de que esta especie reviste gran importancia en Salud Pública, no existen a la fecha estudios sobre su variabilidad genética, desconociéndose si existe o no flujo genético entre las poblaciones rurales y urbanas, endémicas y no endémicas de leishmaniosis visceral (LV). Con base en los genes mitocondriales Citocromo b, RNA de transferencia para Serina, subunidades uno y cuatro de la NADH deshidrogenasa, se estudió la variabilidad genética entre las distintas poblaciones de Lu. evansi en la Costa Caribe, incluyendo la población geográficamente aislada de Isla Fuerte, y una población de Venezuela.
The transmission of Leishmania infantum chagasi by the bite of the Lutzomyia longipalpis to two different vertebrates
Nagila FC Secundino, Vanessa C de Freitas, Carolina C Monteiro, Ana-Clara AM Pires, Bruna A David, Paulo FP Pimenta
Parasites & Vectors , 2012, DOI: 10.1186/1756-3305-5-20
Abstract: This study presents the establishment of a transmission model of Leishmania infantum chagasi by the bite of Lutzomyia longipalpis, the vector of American visceral leishmaniasis. The parasites were successfully transmitted by infected sandfly bites to mice and hamsters, indicating that both animals are good experimental models. The L. infantum chagasi dose that was transmitted in each single bite ranged from 10 to 10, 000 parasites, but 75% of the sandflies transmitted less than 300 parasites.The strategy for initiating infection by sandfly bite of experimental animals facilitates future investigations into the complex and dynamic mechanisms of visceral leishmaniasis. It is important to elucidate the transmission mechanism of vector bites. This model represents a useful tool to study L. infantum chagasi infection transmitted by the vector.Despite the fact that Leishmania is transmitted exclusively by sandfly vectors, a reproducible animal model of Leishmania infection transmitted by sandfly bite was only described in the year 2000 [1].Early investigations showed that infected P. papatasi sandflies can release from 0 to over 1,000 L. major promastigotes through their proboscides by forced feeding [2]. However, a transmission model by bite with P. duboscqui infected with L. major found that the parasite numbers inoculated in the host skin by one insect vector alone could vary from 10 to 100,000 [3].Considering the New World species of Leishmania, using a feeding device of chick skin membrane over culture medium showed that L. longipalpis sandflies infected with Leishmania mexicana (an unnatural vector/parasite pair) expelled an average of 1,000 parasites per fly [4]. Thus, even though L. longipalpis is the vector of L. infantum chagasi in nature, it is permissive in the laboratory to infection with other Leishmania species.In consideration of the continuing prevalence of American visceral leishmaniasis and the paucity of related studies in the literature, our goal was
Induction of Apoptosis by Miltefosine in Iranian Strain of Leishmania infantum Promastigotes
S Khademvatan,MJ Gharavi,L Akhlaghi,A Samadikuchaksaraei
Iranian Journal of Parasitology , 2009,
Abstract: "nBackground: Miltefosine is a new drug of choice for the treatment of visceral leishmaniasis. Numerous experi-mental studies have shown miltefosine is effective on Leishmania donovani, however, effectiveness of miltefos-ine in treatment of L. infantum is not fully understood. The aims of the present study were to evaluate cytotoxic effects of miltefosine on Iranian strain of L. infantum, and to determine its 50% inhibitory concentration (IC50) as well as lethal dose. "nMethods: Anti-L. infantum activity of miltefosine was studied by treatment of cultured promastigotes with vari-ous concentration of miltefosine. MTT assay was used to determine L. infantum viability and the results were expressed as IC50. Annexin-V FLUOS staining was performed to study apoptotic properties of this drug by us-ing FACS flow cytometry."nResults: Miltefosine led to dose-dependent death of L. infantum with features compatible with apoptosis includ-ing cell shrinkage, DNA laddering, and externalization of phosphatidylserine with preservation of integrity of plasma membrane. The 100% effect was achieved at 22 μM and IC50 after 48 hours of incubation was 7 μM."nConclusion: Miltefosine exerts cytotoxic effect on Iranian strain of L. infantum via an apoptosis-related mechanism.
Genetic analysis of a recently detected urban population of Lutzomyia evansi (Diptera: Psychodidae)in Colombia Análisis genético de una población urbana de Lutzomyia evansi (Diptera: Psychodidae), recientemente detectada en Colombia  [cached]
Eduar Elías Bejarano,Winston Rojas,Sandra Uribe,Iván Darío Vélez
Revista de la Sociedad Entomol?3gica Argentina , 2009,
Abstract: Lutzomyia evansi (Nú ez-Tovar) is the vector of the parasite Leishmania infantum in rural zones of Northern Colombia. An attempt was made to determine the origin of a recently detected urban population of Lutzomyia evansi by genetically characterizing specimens from seven geographically distinct localities in the Colombian Caribbean. Insect specimens were collected in rural and urban environments of areas endemic for visceral leishmaniasis or free of the disease. Nine polymorphic sites, nine nucleotide haplotypes and a single aminoacid haplotype were found within the 315 bp fragment sequenced, corresponding to the 3' end of the cytochrome b mitochondrial gene. Paired genetic distances between the haplotypes, estimated with the Kimura two-parameters model, varied from 0,0032-0,0194. Analysis revealed low genetic variability between specimens from urban and rural localities. Several of the sand flies collected in the city of Sincelejo (department of Sucre), where autochthonous visceral leishmaniasis cases have appeared in recent years, were genetically similar to those of a rural focus of the disease (El Contento, on the neighboring department of Córdoba). The epidemiological implications of this finding for Leishmania infantum transmission in the Colombian Caribbean are discussed. Lutzomyia evansi (Nú ez-Tovar) es el insecto transmisor del parásito Leishmania infantum en zonas rurales del norte de Colombia. Con el propósito de establecer el probable origen de una población urbana del vector, detectada en a os recientes, se caracterizaron genéticamente ejemplares de Lutzomyia evansi de siete localidades geográficas del Caribe Colombiano. Los flebotomíneos fueron recolectados en ambientes rurales y urbanos de zonas endémicas y no endémicas de leishmaniasis visceral. Dentro del fragmento secuenciado de 315 pb correspondiente al extremo 3' del gen mitocondrial citocromo b, se encontraron nueve sitios polimórficos, nueve haplotipos nucleotídicos y un solo haplotipo aminoacídico. Las distancias genéticas pareadas entre los haplotipos, estimadas con el modelo de Kimura de dos parámetros, oscilaron entre 0,0032 y 0,0194. El análisis reveló la existencia de una baja variabilidad genética entre especímenes de localidades urbanas y rurales. Varios de los flebotomíneos recolectados en la zona urbana de la ciudad de Sincelejo, departamento de Sucre, donde en a os recientes aparecieron casos autóctonos de leishmaniasis visceral, fueron genéticamente similares a los de El Contento, en el cercano departamento de Córdoba, foco rural de la enfermedad. Se discuten las impl
Dosis diagnóstica y umbral de resistencia de Lutzomyia evansi (Diptera: Psychodidae), a dos insecticidas utilizados en salud pública en Colombia: deltametrina y lambdacihalotrina
Henriquez,Caterine; Pereira,Yaneth; Cochero,Suljey; Bejarano,Eduar Elías;
Revista de la Sociedad Entomol?3gica Argentina , 2009,
Abstract: insecticides are an important tool for controlling insect vectors of microorganism pathogens. the aim of this study was to determine the diagnostic dosages of deltamethrin and lambdacyhalothrin for the sand fly lutzomyia evansi (nú?ez-tovar), a vector of leishmania infantum in colombia. sand flies were collected in the estación experimental de fauna silvestre of colosó, sucre, a natural reserve that had not been previously treated with insecticides. glass bottles were used for bioassays, following the simplified method (cdc) for detecting insecticide resistance. wild females of l. evansi were exposed to different concentrations of insecticides during a test period of 80 minutes. the diagnostic dosages of deltamethrin and lambdacyhalothrin were established in 0,0007%, and 0,00035%, respectively, and the resistance threshold was calculated to be ten minutes for both insecticides, exposure period during which the mortality reached 100%. the time-mortality data suggest that lambdacyhalothrin have a lethal effect on l. evansi at a lower concentration than deltamethrin. the last insecticide was less toxic than lambdacyhalothrin.
Canine experimental infection: intradermal inoculation of Leishmania infantum promastigotes
Santos-Gomes, Gabriela M;Campino, Lenea;Abranches, Pedro;
Memórias do Instituto Oswaldo Cruz , 2000, DOI: 10.1590/S0074-02762000000200010
Abstract: five mixed breed dogs were inoculated intradermally (id) with cultured virulent stationary phase promastigotes of leishmania infantum nicole, 1908 stocks recently isolated. parasite transformations in the skin of id infected dogs were monitored from the moment of inoculation and for 48 h, by skin biopsies. anti-leishmania antibody levels were measured by indirect immunofluorescence assay, counterimmunoelectrophoresis and direct agglutination test, and clinical conditions were examined. thirty minutes after id inoculation the first amastigotes were visualised and 3 to 4 h after inoculation the promastigotes were phagocyted by neutrophils and by a few macrophages. these cells parasitised by amastigotes progressively disappeared from the skin and 24 h after inoculation parasites were no longer observed. local granulomes were not observed, however, serological conversion for antibodies anti-leishmania was achieved in all dogs. direct agglutination test was the only technique positive in all inoculated dogs. amastigotes were found in the popliteal lymph node in one dog three months after inoculation. this work demonstrates that, with this inoculum, the promastigotes were transformed into amastigotes and were up taken by neutrophils and macrophages. the surviving parasites may have been disseminated in the canine organism, eliciting a humoral response in all cases.
Canine experimental infection: intradermal inoculation of Leishmania infantum promastigotes
Santos-Gomes Gabriela M,Campino Lenea,Abranches Pedro
Memórias do Instituto Oswaldo Cruz , 2000,
Abstract: Five mixed breed dogs were inoculated intradermally (ID) with cultured virulent stationary phase promastigotes of Leishmania infantum Nicole, 1908 stocks recently isolated. Parasite transformations in the skin of ID infected dogs were monitored from the moment of inoculation and for 48 h, by skin biopsies. Anti-Leishmania antibody levels were measured by indirect immunofluorescence assay, counterimmunoelectrophoresis and direct agglutination test, and clinical conditions were examined. Thirty minutes after ID inoculation the first amastigotes were visualised and 3 to 4 h after inoculation the promastigotes were phagocyted by neutrophils and by a few macrophages. These cells parasitised by amastigotes progressively disappeared from the skin and 24 h after inoculation parasites were no longer observed. Local granulomes were not observed, however, serological conversion for antibodies anti-Leishmania was achieved in all dogs. Direct agglutination test was the only technique positive in all inoculated dogs. Amastigotes were found in the popliteal lymph node in one dog three months after inoculation. This work demonstrates that, with this inoculum, the promastigotes were transformed into amastigotes and were up taken by neutrophils and macrophages. The surviving parasites may have been disseminated in the canine organism, eliciting a humoral response in all cases.
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