920 resultados para holocene beach sand


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Early Cretaceous flagellates with characters typical of trypanosomatids were found in the gut of sand fly larvae, as well as in surrounding debris, in Burmese amber. This discovery supports a hypothesis in which free-living trypanosomatids could have been acquired by sand fly larvae in their feeding environment and then carried transtadially into the adult stage. At some point in time, specific genera were introduced into vertebrates, thus establishing a dixenous life cycle.

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This paper describes the modifications made to the original model of the Disney trap, with a view to easier handling of the same, greater practicability in the collection of sand flies, protection of the animal bait and durability of the trap in the field.

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Visceral leishmaniasis (VL) has been naturally transmitted in periurban areas due to the emergence and reemergence of its vectors in such areas. Aimed to further knowledge on ecological aspects affecting the occurrence of phlebotomine sand flies in VL transmission areas in the municipality of Várzea Grande, state of Mato Grosso (MT), Brazil, sand fly captures were carried out. Monthly collections of sand flies were undertaken with CDC light-traps, which were left in both intradomiciliary and peridomiciliary areas of ten residences during four consecutive days between January 2004 and June 2006. Twenty-two species of genus Lutzomyia and one of Brumptomyia were captured. The most abundant species was Lutzomyia longipalpis (65.23%), followed by L. evandroi (16.26%), L. lenti (7.69%), L. whitmani (4.92%), L. sallesi (2.34%) and L. termitophila (1.32%). The highest density of the main VL vector, L. longipalpis, was found in peridomiciliary areas, mostly males. No significant correlation was found between environment (temperature, air relative humidity and rain fall) and phlebotomine density; although a slight increase in sand fly density has been observed in the period following rainfalls, particularly L. longipalpis. No correlation was observed between distribution and density of L. longipalpis, prevalence of human VL cases and the presence of serologically positive dogs. The presence of infected dogs, increased vector density, susceptibility rate and interruption of epidemiological surveillance may raise the risk of VL transmission to man in Várzea Grande.

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A new species of parthenogenetic, autogenic and apparently extremely endemic phlebotomine is described from a sandstone cave located in primary terra firme forest to the North of the city of Manaus. Specimens were collected in the aphotic zone of the Refúgio do Maruaga cave by light trap and reared from bat guano. The adult morphology suggests a closer relationship to some Old World Phlebotominae than to species of Lutzomyia França encountered in the surrounding rainforest, but it shares characteristics with the recently proposed Neotropical genera Edentomyia Galati, Deanemyia Galati and Oligodontomyia Galati.

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Phlebotomine sand flies are often captured with human bait and/or light traps, either with or without an animal bait. More recently, synthetic attractants have been used as bait in traps to improve the capture of phlebotomine sand flies as well as other insects of medical and veterinary importance. The aim of the present study was to evaluate the effects of the kairomone 1-octen-3-ol (octenol) and the synthetic human odor BG-Mesh LureTM (BGML - lactic acid, caproic acid and ammonia) baited in modified CDC light traps on the capture of phlebotomine sand flies. The experiments followed the 5x5 Latin square design. Among the species caught, Lutzomyia intermedia apparently presented a dose-dependent response to octenol. The response obtained with the BGML, alone or in combination with octenol (5 mg/h), indicated some degree of attractiveness of these baits to different phlebotomine sand fly species. Octenol seems to be more attractive to L. intermedia than to Lutzomyia longipalpis, while the BGML presented a higher success in capturing L. longipalpis. When the components of the BGML were used separately, there was no increase in catching the female of L. intermedia. Apparently, there was no synergistic effect between the octenol and the BGML. In conclusion, the octenol and the BGML were demonstrated to be possible baits to attract some phlebotomine sand fly species.

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Three years after the first report of Lutzomyia longipalpis in Clorinda, Argentina, a border city near Asunción, Paraguay, the city was surveyed again. Lu. longipalpis was found clustered in the same neighbourhoods in 2007 as in 2004, even though the scattered distribution of canine visceral leishmaniasis was more related to the traffic of dogs through the border.

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We surveyed areas of the state of Rondônia in western Amazon for phlebotomine, which are potential vectors of leishmaniasis. A total of 5,998 specimens were captured, resulting in the identification of 48 species within the Lutzomyia (99.98%) and Brumptomyia (0.02%) genera. The predominant species was Lutzomyia davisi, followed by Lutzomyia umbratilis, Lutzomyia llanosmartinsi, Lutzomyia c. carrerai, Lutzomyia dendrophyla, Lutzomyia nevesi and Lutzomyia whitmani. All sand flies identified as vectors for cutaneous leishmaniasis in Brazil, i.e., Lu. davisi, Lu. umbratilis, Lu. c. carrerai and Lu. whitmani, were found in the surveyed areas.

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Feline coprolites were examined for parasites with the aim of studying ancient infections that occurred in the Patagonian region during the Holocene period. Eggs compatible to Trichuris sp., Calodium sp., Eucoleus sp., Nematodirus sp., Oesophagostomum sp. (Nematoda), Monoecocestus sp. (Cestoda) and Eimeria macusaniensis (Coccidia) were recovered from faecal samples. The results obtained from the analysis provide evidence of consumption by felids of the viscera of both rodents and camelids. This knowledge allows for improved explanations as to the distribution of parasitism and its significance to the health of humans and animals inhabiting the area under study during the Middle Holocene.

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Canine American visceral leishmaniasis and American cutaneous leishmaniasis (ACL) cases have been recorded in Espírito Santo do Pinhal. The aim of this study was to gather knowledge of the sand fly community and its population ecology within the municipality. Captures were made weekly over a period of 15 months in the urban, periurban and rural areas of the municipality, using automatic light traps. A total of 5,562 sand flies were collected, comprising 17 species. The most abundant species were Nyssomyia whitmani and Pintomyia pessoai in the rural area, Lutzomyia longipalpis and Ny. whitmani in the periurban area and Lu. longipalpis in the urban area. The highest species richness and greatest index species diversity were found in the rural area. The similarity index showed that urban and periurban areas were most alike. Lu. longipalpis was found in great numbers during both dry and humid periods. The presence of dogs infected with Leishmania infantum chagasi in the urban area indicates a high risk for the establishment of the disease in the region. A high abundance of Ny. whitmani and Pi. pessoai in the rural and periurban areas indicates the possibility of new cases of ACL occurring in and spreading to the periurban area of Espírito Santo do Pinhal.

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The phlebotomine sand fly Lutzomyia velezi sp.nov. was described and illustrated from male specimens collected by light trap in the Reserva Natural Cañon del Río Claro in the Central Cordillera of the Colombian Andes. The new species belongs to the series sanguinaria of the subgenus Helcocyrtomyia, which is represented in Colombia by Lutzomyia cirrita, Lutzomyia hartmanni, Lutzomyia sanguinaria, Lutzomyia scorzai, Lutzomyia sp. of Pichindé and Lutzomyia tortura. The new species can be differentiated from others of the subgenus by the combination of the following characteristics: long antennal ascoids, reaching level of the papilla, coxite with a single basal seta and fifth palpomere longer than or equal to the sum of the lengths of the third and fourth palpomeres.

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The bionomics of phlebotomine sand flies (Diptera: Psychodidae) were studied for two successive years (January 1996-December 1997) at 12 collecting stations representing six sectors of the province of Al-Baha, Saudi Arabia. The predominant species was Phlebotomus bergeroti (41.7%), followed by lesser numbers of Phlebotomus sergenti (11%), Phlebotomus arabicus (10.6%), Sergentomyia tiberiadis (10.5%), Phlebotomus papatasi (10.2%), Sergentomyia antennata (9.6%), Phlebotomus alexandri (3%), Phlebotomus orientalis (2.3%) and Sergentomyia clydei (1.1%). The distribution of the collected species including species that are elsewhere known to act as vectors of human cutaneous leishmaniasis were distributed across different altitudes in Al-Baha. P. bergeroti, P. papatasi and P. arabicus were more abundant indoors; however, P. sergenti was more abundant outdoors. Sand fly populations exhibited three patterns of seasonal abundance in terms of their monthly activity. P. bergeroti, P. sergenti and P. arabicus were found to be naturally infected with Leishmania-like flagellates at an infection rate of 0.2%.

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Sand flies within the genus Lutzomyia serve as the vectors for all species of the protozoan parasite Leishmania in the New World. In this paper, we present a summary of the 29 species of Lutzomyia and one of Brumptomyia previously reported for Nicaragua and report results of our recent collections of 565 sand flies at eight localities in the country from 2001-2006. Lutzomyia longipalpis was the predominant species collected within the Pacific plains region of western Nicaragua, while Lutzomyia cruciata or Lutzomyia barrettoi majuscula were the species most frequently collected in the central highlands and Atlantic plains regions. The collection of Lutzomyia durani (Vargas & Nájera) at San Jacinto in July 2001 is a new record for Nicaragua. Leishmaniasis is endemic to Nicaragua and occurs in three forms: cutaneous, mucocutaneous and visceral leishmaniasis. Cutaneous infections are the most prevalent type of leishmaniasis in Nicaragua and they occur in two different clinical manifestations, typical cutaneous leishmaniasis and atypical cutaneous leishmaniasis, depending on the species of the infecting Leishmania parasite. The distribution of sand flies collected during this study in relation to the geographic distribution of clinical forms of leishmaniasis in the country is also discussed.

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Over the last 20 years, there has been an increase in the number of leishmaniasis cases in Brazil. Belo Horizonte (BH) is one of the most highly populated Brazilian cities that is affected by visceral leishmaniasis (VL). The health services in BH are coordinated by a central nucleus that is subdivided into nine sanitary districts. Historically, the highest level of human VL cases was found in the northeast sanitary district (NSD). The objective of our study was to detect Leishmania infection in the phlebotomine sand flies collected in the NSD by dissection and molecular approaches. Following the occurrence of human VL cases in 2005, entomological captures were performed from July 2006-June 2007. Out of the 245 sand flies dissected, only three Lutzomyia longipalpis spp contained flagellates. The female sand flies were grouped into 120 pools according to date, collection site and species, with approximately 10 individual sand flies in each pool. Subsquently, the DNA was extracted and Leishmania spp and other parasites were detected and identified by polymerase chain reaction (PCR) and PCR-restriction fragment length polymorfism. Leishmania infantum was present in at least 19% of the Lu. longipalpis collected, in 3.8% of the Nyssomiya whitmani collected, in 33.3% of the Evandromiya termitophila collected and in 14.3% of the Nyssomiya intermedia collected. When the females of the cortelezzii complex were compared with each other, 3.2% of the females were infected with Leishmania braziliensis, whereas 3.2% of the females were infected with trypanosomatids.

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During a blood meal, Lutzomyia intermedia sand flies transmit Leishmania braziliensis, a parasite causing tegumentary leishmaniasis. In experimental leishmaniasis, pre-exposure to saliva of most blood-feeding sand flies results in parasite establishment in absence of any skin damages in mice challenged with dermotropic Leishmania species together with saliva. In contrast, pre-immunization with Lu. intermedia salivary gland sonicate (SGS) results in enhanced skin inflammatory exacerbation upon co-inoculation of Lu. intermedia SGS and L. braziliensis. These data highlight potential unique features of both L. braziliensis and Lu. intermedia. In this study, we investigated the genes modulated by Lu. intermedia SGS immunization to understand their potential impact on the subsequent cutaneous immune response following inoculation of both SGS and L. braziliensis. The cellular recruitment and global gene expression profile was analyzed in mice repeatedly inoculated or not with Lu. intermedia. Microarray gene analysis revealed the upregulation of a distinct set of IFN-inducible genes, an immune signature not seen to the same extent in control animals. Of note this INF-inducible gene set was not induced in SGS pre-immunized mice subsequently co-inoculated with SGS and L. braziliensis. These data suggest the parasite prevented the upregulation of this Lu. intermedia saliva-related immune signature. The presence of these IFN-inducible genes was further analyzed in peripheral blood mononuclear cells (PBMCs) sampled from uninfected human individuals living in a L. braziliensis-endemic region of Brazil thus regularly exposed to Lu. intermedia bites. PBMCs were cultured in presence or absence of Lu. intermedia SGS. Using qRT-PCR we established that the IFN-inducible genes induced in the skin of SGS pre-immunized mice, were also upregulated by SGS in PBMCs from human individuals regularly exposed to Lu. intermedia bites, but not in PBMCs of control subjects. These data demonstrate that repeated exposure to Lu. intermedia SGS induces the expression of potentially host-protective IFN-inducible genes.

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