Leishmaniasis in Brazil. XXIV. Natural flagellate infections of sandflies (Diptera: Psychodidae) in Pará State, with particular reference to the rôle of Psychodopygus wellcomei as the vector of Leishmania braziliensis braziliensis in the Serra dos Carajás

Potential vectors of Leishmania spp. in an Atlantic Forest conservation unit in northeastern Brazil under anthropic pressure

BACKGROUND

Phlebotomines are a group of insects which include vectors of the Leishmania parasites that cause visceral leishmaniasis (VL) and cutaneous leishmaniasis (CL), diseases primarily affecting populations of low socioeconomic status. VL in Brazil is caused by Leishmania infantum, with transmission mainly attributed to Lutzomyia longipalpis, a species complex of sand fly, and is concentrated mainly in the northeastern part of the country. CL is distributed worldwide and occurs in five regions of Brazil, at a higher incidence in the north and northeast regions, with etiological agents, vectors, reservoirs and epidemiological patterns that differ from VL. The aim of this study was to determine the composition, distribution and ecological relationships of phlebotomine species in an Atlantic Forest conservation unit and nearby residential area in northeastern Brazil.

METHODS

Centers for Disease Control and Shannon traps were used for collections, the former at six points inside the forest and in the peridomestic environment of surrounding residences, three times per month for 36 months, and the latter in a forest area, once a month for 3 months. The phlebotomines identified were compared with climate data using simple linear correlation, Pearson's correlation coefficient and cross-correlation. The estimate of ecological parameters was calculated according to the Shannon-Wiener diversity index, standardized index of species abundance and the dominance index.

RESULTS

A total of 75,499 phlebotomines belonging to 11 species were captured in the CDC traps, the most abundant being Evandromyia walkeri, Psychodopygus wellcomei and Lu. longipalpis. Evandromyia walkeri abundance was most influenced by temperature at collection time and during the months preceding collection and rainfall during the months preceding collection. Psychodopygus wellcomei abundance was most affected by rainfall and relative humidity during the collection month and the month immediately preceding collection time. Lutzomyia longipalpis abundance showed a correlation with temperature and the rainfall during the months preceding collection time. The Shannon trap contained a total of 3914 phlebotomines from these different species. Psychodopygus wellcomei, accounting for 91.93% of the total, was anthropophilic and active mainly at night.

CONCLUSIONS

Most of the species collected in the traps were seasonal and exhibited changes in their composition and population dynamics associated with local adaptions. The presence of vectors Ps. wellcomei and Lu. longipalpis underscore the epidemiological importance of these phlebotomines in the conservation unit and surrounding anthropized areas. Neighboring residential areas should be permanently monitored to prevent VL or CL transmission and outbreaks.

Insights into the proteomic profile and gene expression of Lutzomyia longipalpis-derived Lulo cell line

BACKGROUND

Lutzomyia longipalpis-derived cell line (Lulo) has been suggested as a model for studies of interaction between sandflies and Leishmania.

OBJECTIVES

Here, we present data of proteomic and gene expression analyses of Lulo cell related to interactions with Leishmania (Viannia) braziliensis.

METHODS

Lulo cell protein extracts were analysed through a combination of two-dimensional gel electrophoresis and mass spectrometry and resulting spots were further investigated in silico to identify proteins using Mascot search and, afterwards, resulting sequences were applied for analysis with VectorBase.

RESULTS

Sixty-four spots were identified showing similarities to other proteins registered in the databases and could be classified according to their biological function, such as ion-binding proteins (23%), proteases (14%), cytoskeletal proteins (11%) and interactive membrane proteins (9.5%). Effects of interaction with L. (V.) braziliensis with the expression of three genes (enolase, tubulin and vacuolar transport protein) were observed after an eight-hour timeframe and compared to culture without parasites, and demonstrated the impact of parasite interaction with the expression of the following genes: LLOJ000219 (1.69-fold), LLOJ000326 (1.43-fold) and LLOJ006663 (2.41-fold).

CONCLUSIONS

This set of results adds relevant information regarding the usefulness of the Lulo cell line for studies with Leishmania parasites that indicate variations of protein expression.

Phlebotomines (Diptera: Psychodidae) from a Urban Park of Belém, Pará State, Northern Brazil and Potential Implications in the Transmission of American Cutaneous Leishmaniasis

In urban ecotourism parks, the life cycle of American cutaneous leishmaniasis (ACL) agents can remain established, where phlebotomines may comprise potential risks for visitors. The present study aimed to survey the phlebotomine fauna of a forest park 'Bosque Rodriques Alves-Jardim Botânico da Amazônia' (BRAJBA), in the urban area of Belém, Brazil. The park was monthly surveyed in 2018 using CDC light traps placed in ground and canopy strata. Leishmania spp. isolated from dissected females were characterized by polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP) analysis. Fluctuations in specimen capture were correlated with rainfall. Nyssomyia antunesi (Coutinho, 1939) was predominant for all surveyed ecotopes and capture methods in both areas. Females of Ny. antunesi resting on tree bases were observed attempting to bite researchers during early morning. One Bichromomyia flaviscutellata (Mangabeira, 1942) and one Trichophoromyia brachipyga (Mangabeira, 1942) were found naturally infected by flagellates. Only the strain from Th. brachipyga was isolated and characterized as Leishmania (Viannia) lainsoni Silveira, Shaw, Braga and Ishikawa, 1987. Monthly fluctuations of the three most abundant species, Ny. antunesi, Trichophoromyia ubiquitalis (Mangabeira, 1942) and Th. brachypiga, had statistically significant negative correlations with rainfall. The present study provided further information to better understand ACL ecology in the Belém urban area, where the urban parks surveyed appeared to offer potential risk of contracting the disease, thus requiring environmental management. These observations highlighted the need for including Ny. antunesi, Bi. flaviscutellata, Th. ubiquitalis, and Th. brachypiga in the priority list for continuous entomological surveillance.

Ecological aspects of Phlebotomines (Diptera: Psychodidae) and the transmission of American cutaneous leishmaniasis agents in an Amazonian/ Guianan bordering area

BACKGROUND

An entomological study was conducted in the municipality of Oiapoque (lower Oyapock River Basin) in the Brazilian side bordering French Guiana to gain information on the transmission pattern of American cutaneous leishmaniasis (ACL) in that region, presumed to reflect the classical Amazonian/Guianan enzootic scenario.

METHODS

Three ecologically isolated forested areas near urban environments were surveyed during the rainy and dry seasons of 2015 and 2016, using a multi-trapping approach comprising ground-level and canopy light traps, black and white colored cloth Shannon traps and manual aspiration on tree bases. Female phlebotomines were dissected to find infections and isolate flagellates from Leishmania spp. The strains were characterized by restriction fragment length polymorphism analysis and compared with those of local ACL cases and World Health Organization reference strains.

RESULTS

Nyssomyia umbratilis, Trichopygomyia trichopyga and Evandromyia infraspinosa were the most frequently found species. Findings on relative abundance, spatiotemporal vector/ACL congruence, natural infections and anthropophilic insights strengthened the Guianan classical transmission of Leishmania (Viannia) guyanensis by Ny. umbratilis and suggested further investigations for Ev. infraspinosa. Nyssomyia umbratilis showed an eclectic feeding habit, including bird blood. Ecological data and literature reports also included Psychodopygus squamiventris maripaensis and Bichromomyia flaviscutellata on the list of suspected vectors.

CONCLUSIONS

These findings contributed to understanding ACL ecoepidemiology in the Amazonian/Guianan scenario. Local studies are required to better comprehend the Leishmania spp. enzootic mosaic in specific ecotopes.

Entomological surveys of Lutzomyia flaviscutellata and other vectors of cutaneous leishmaniasis in municipalities with records of Leishmania amazonensis within the Bragança region of Pará State, Brazil

In southeast Amazon, Lutzomyia (Nyssomyia) flaviscutellata is the incriminated vector of Leishmania (Leishmania) amazonensis, a causative agent of zoonotic cutaneous leishmaniasis (CL). The optimal methods for surveying Lu. flaviscutellata were investigated in the Bragança region, northeast Pará State, Brazil, selected for the presence of Le. amazonensis. The performances of modified Disney traps and CDC light traps were compared in four ecotopes within and around four village transects during the wet and dry seasons. The physiological age of female sand flies was estimated and natural infection by flagellates was evaluated by dissection. Disney traps were better for detecting the presence of Lu. flaviscutellata, while CDC traps performed well for detecting Lutzomyia (Nyssomyia) antunesi, suspected vector of Leishmania lindenbergi. The former was more abundant during the wet season, when female flies were naturally infected with Le. amazonensis. These findings identified the environments of local transmission. In order to improve surveys of Lu. flaviscutellata as part of integrated epidemiological surveillance of CL, our recommendations include focusing vector surveys with Disney traps on forest fragments where people work, during the seasonal peak of the vector. Further field studies are required to make model-based predictions of seasonal variations in the vectorial capacity of vector populations.

Natural Leishmania (Viannia) infections of phlebotomines (Diptera: Psychodidae) indicate classical and alternative transmission cycles of American cutaneous leishmaniasis in the Guiana Shield, Brazil

From 1996 to 1999 multi-trapping methods (Center of Diseases Control, CDC) light traps, light-baited Shannon traps, and aspiration on tree bases) were used to study the phlebotomine fauna of the "Serra do Navio" region of the Brazilian State of Amapá, which is part of the Guiana Shield. Fifty-three species were identified among 8,685 captured individuals. The following species, associated with the transmission of American cutaneous leishmaniasis in Amazonian Brazil, were captured: Nyssomyia umbratilis (3,388), Psychodopygus squamiventris maripaensis (995), Ny. anduzei (550), Trichophoromyia ubiquitalis (400), Ny. whitmani (291), Ps. paraensis (116), and Bichromomyia flaviscutellata (50). Flagellate infections were detected in 45 flies. Of the 19 parasites isolated in vitro, 15 were Leishmania (Viannia) guyanensis (13 in Ny. umbratilis, 1 in Ny. whitmani, 1 in Ny. anduzei) and three were L. (V.) naiffi (2 in Ps. s. maripaensis, 1 in Ny. anduzei). The results indicate the participation of three phlebotomine species in the transmission of L. (V.) guyanensis and two species in that of L. (V.) naiffi, and show that the same phlebotomine species is involved in the transmission of different Leishmania (Viannia) species in the Guianan/Amazon region. A review of the literature together with the results of the present study, and other published and unpublished results, indicate that eight phlebotomine species potentially participate in the transmission of Leishmania (Viannia) naiffi in Amazonia.

Aspects on the Ecology of Phlebotomine Sand Flies (Diptera: Psychodidae) From Guaraí, State of Tocantins, Brazil, Endemic Area for American Cutaneous Leishmaniasis

In Brazil, American cutaneous leishmaniasis (ACL) ecology involves a diversity of Leishmania species transmitted by different sand fly species. Workers involved in agricultural activities are those mainly affected by ACL in some regions from Tocantins State (TO), Brazil, where the disease can be established in new settlements. The objective of this study was to examine the seasonal and hourly frequency of sand fly species, focusing on the potential vectors of ACL, in a settlement in Guaraí (TO), an ACL transmission area. Sand flies were captured in forested area close to Pedra Branca Agricultural Project settlement, from March 2006 until December 2007, using Shannon trap. Monthly captures were made from 06:00 p.m. to 10:00 p.m., and 24-h captures were done twice per semester, from 06:00 a.m. to 06:00 a.m. A total of 10,089 specimens from 30 species were identified. Psychodopygus complexus Mangabeira, Psychodopygus llanosmartinsi Fraiha & Ward, and Nyssomyia antunesi Coutinho were the most abundant species. Nyssomyia antunesi was more frequent during the dry period, whereas Ps. complexus and Ps. llanosmartinsi had high frequencies during the rainy season. Precipitation was positively correlated with Ps. complexus and Ps. llanosmartinsi abundance, and negatively correlated with Ny. antunesi During 24-h captures, the majority of specimens were captured during the night followed by a decrease at dawn. The behavior and previous finding of natural infection by Leishmania (Viannia) braziliensis of Ps. complexus led us to the conclusion that this species can be a potential vector of L. (V.) braziliensis during the rainy season in Guaraí.

Anthropophily of Lutzomyia wellcomei (Diptera: Psychodidae) in an Atlantic Forest Conservation Unit in Northeast Brazil

Lutzomyia wellcomei (Fraiha, Shaw & Lainson) (Diptera: Psychodidae) can act as an important vector of Leishmania (Viannia) braziliensis This study presents the results of collections carried out in a fragment of Atlantic Forest in a Conservation Unit of Rio Grande do Norte state. Collections occurred over 12 consecutive months using Shannon and CDC traps. A total of 777 sand flies from eight species were collected: Lutzomyia walkeri (Newstead), Lutzomyia evandroi (Costa Lima & Antunes), Lutzomyia wellcomei (Fraiha, Shaw & Lainson), Lutzomyia sordellii (Shannon & Del Ponte), Lutzomyia brasiliensis (Costa Lima), Lutzomyia lenti (Mangabeira), Lutzomyia longipalpis (Lutz & Neiva), and Lutzomyia abonnenci (Floch & Chassignet). Lutzomyia wellcomei was the most abundant species using the Shannon trap (97%) and L. walkeri in the CDC trap (81%). It is important to note the abundance of L. wellcomei in Shannon trap collections, which favors the capture of anthropophilic species. Lutzomyia wellcomei was only present in months where rainfall was above 100 mm, confirming it as a species adapted to wetter months.

Natural Leishmania (Viannia) spp. infections in phlebotomine sand flies (Diptera: Psychodidae) from the Brazilian Amazon region reveal new putative transmission cycles of American cutaneous leishmaniasis

In Amazonian Brazil the etiological agents of American cutaneous leishmaniasis (ACL) belong to at least seven Leishmania species but little is known about the putative phlebotomine sand fly vectors in different biomes. In 2002–2003 a survey of the phlebotomine fauna was undertaken in the “Floresta Nacional do Tapajós”, Belterra municipality, in the lower Amazon region, western Pará State, Brazil, where we recently confirmed the presence of a putative hybrid parasite, L. (V.) guyanensis × L. (V.) shawi shawi. Sand flies were collected from Centers for Disease Control (CDC) light traps, Shannon traps and by aspiration on tree bases. Females were dissected and attempts to isolate any flagellate infections were made by inoculating homogenized midguts into Difco B⁴⁵ medium. Isolates were characterized by monoclonal antibodies and isoenzyme electrophoresis. A total of 9,704 sand flies, belonging to 68 species or subspecies, were collected. Infections were found in the following sand flies: L. (V.) naiffi with Psychodopygus hirsutus hirsutus (1) and Ps. davisi (2); and L. (V.) shawi shawi with Nyssomyia whitmani (3) and Lutzomyia gomezi (1). These results provide strong evidence of new putative transmission cycles for L. (V.) naiffi and L. (V.) s. shawi.

Sand flies (Diptera, Psychodidae, Phlebotominae), vectors of Leishmania protozoa, at an Atlantic Forest Conservation Unit in the municipality of Nísia Floresta, Rio Grande do Norte state, Brazil

Background

Sand flies are insect vectors of protozoa from the genus Leishmania, causative parasites of visceral and American tegumentary leishmaniases. The present study discusses the bioecological aspects of sand fly species, transmitters of Leishmania protozoa, in different ecotopes of an Atlantic Forest Conservation Unit located in the metropolitan region of Natal, Rio Grande do Norte state, Brazil.

Methods

Two monthly captures were made in 1 year, using CDC light traps, in two anthropized and two preserved environments.

Results

A total of 2936 sand flies belonging to the following ten species were captured: Evandromyia walkeri, Evandromyia evandroi, Psychodopygus wellcomei, Sciopemyia sordellii, Psathyromyia brasiliensis, Lutzomyia longipalpis, Evandromyia lenti, Psathyromyia shannoni, Nyssomyia whitmani and Nyssomyia intermedia. The most common species was E. walkeri (77.6 %), followed by E. evandroi (17.5 %). Forest was the site with the greatest abundance (32.4 %), followed by bamboo grove (26.3 %).

Conclusions

Sand flies were generally more abundant in the rainy season and L. longipalpis, a vector species of Leishmania infantum, was adapted to anthropized environments. It was confirmed that P. wellcomei, a vector of Leishmania braziliensis in Amazônia, is a species associated with more preserved environments, and occurs only in the rainy season.

Intradomiciliary and peridomiciliary captures of sand flies (Diptera: Psychodidae) in the leishmaniasis endemic area of Chapare province, tropic of Cochabamba, Bolivia

In South America, cutaneous leishmaniasis is the most frequent clinical form of leishmaniasis. Bolivia is one of the countries with higher incidence, with 33 cases per 100,000 individuals, and the disease is endemic in 70% of the territory. In the last decade, the number of cases has increased, the age range has expanded, affecting children under 5 years old, and a similar frequency between men and women is found. An entomological study with CDC light traps was conducted in three localities (Chipiriri, Santa Elena and Pedro Domingo Murillo) of the municipality of Villa Tunari, one of the main towns in the Chapare province (Department of Cochabamba, Bolivia). A total of 16 specimens belonging to 6 species of the genus Lutzomyia were captured: Lu. aragaoi, Lu. andersoni, Lu. antunesi, Lu. shawi, Lu. yuilli yuilli and Lu. auraensis. Our results showed the presence of two incriminated vectors of leishmaniasis in an urbanized area and in the intradomicile. More entomological studies are required in the Chapare province to confirm the role of vector sand flies, the intradomiciliary transmission of the disease and the presence of autochthonous cases of cutaneous leishmaniasis.

Brito ME, Carvalho FG, Carvalho AWS, Soares F, Carvalho SM, Costa PL, Zampieri R, Floeter-Winter LM, Shaw JJ, Brandão-Filho SP. Infectiousness of Sylvatic and Synanthropic Small Rodents Implicates a Multi-host Reservoir of Leishmania (Viannia) braziliensis

Background

The possibility that a multi-host wildlife reservoir is responsible for maintaining transmission of Leishmania (Viannia) braziliensis causing human cutaneous and mucocutaneous leishmaniasis is tested by comparative analysis of infection progression and infectiousness to sandflies in rodent host species previously shown to have high natural infection prevalences in both sylvatic or/and peridomestic habitats in close proximity to humans in northeast Brazil.

Methods

The clinical and parasitological outcomes, and infectiousness to sandflies, were observed in 54 colonized animals of three species (18 Necromys lasiurus, 18 Nectomys squamipes and 18 Rattus rattus) experimentally infected with high (5.5×10⁶/ml) or low (2.8×10⁵/ml) dose L. (V.) braziliensis (MBOL/BR/2000/CPqAM95) inoculum. Clinical signs of infection were monitored daily. Whole animal xenodiagnoses were performed 6 months post inoculation using Lutzomyia longipalpis originating from flies caught in Passira, Pernambuco, after this parasite evaluation was performed at necropsy. Heterogeneities in Leishmania parasite loads were measured by quantitative PCR in ear skin, liver and spleen tissues.

Results

All three rodent species proved to establish infection characterized by short-term self-resolving skin lesions, located on ears and tail but not on footpads (one site of inoculation), and variable parasite loads detected in all three tissues with maximum burdens of 8.1×10³ (skin), 2.8×10³ (spleen), and 8.9×10² (liver). All three host species, 18/18 N. lasiurus, 10/18 N. squamipes and 6/18 R. rattus, also proved infectious to sandflies in cross-sectional study. R. rattus supported significantly lower tissue parasite loads compared to those in N. lasiurus and N. squamipes, and N. lasiurus appeared to be more infectious, on average, than either N. squamipes or R. rattus.

Conclusions

A multi-host reservoir of cutaneous leishmaniasis is indicated in this region of Brazil, though with apparent differences in the competence between the rodent species. The results provide preliminary insights into links between sylvatic and peri-domestic transmission cycles associated with overlaps in the rodent species’ ecological niches.

Across the Americas, Leishmania (V.) braziliensis is the predominant Leishmania species causing cutaneous and mucocutaneous leishmaniasis in humans. Transmitted by Phlebotomine sandflies, questions remain about the epidemiological contributions of the numerous zoonotic and more domestic host species. Domestication of the principal vector and human infection patterns suggest that human infection risk is predominantly peridomestic, whereas control strategies will be more complex if there is a link to a wildlife transmission cycle. Almost no studies have been conducted on the transmission potential of natural hosts of L. (V.) braziliensis. This study evaluates the infectiousness of experimentally infected natural rodent host species, that in different ecological habitats are proposed to act as a single or a multi-host reservoir. Clinical and parasitological development, and the ability to transmit Leishmania to sandflies, was observed under experimental conditions using a single strain of L. (V.) braziliensis isolated from the wild rat, Necromys lasiurus. Xenodiagnoses were performed with laboratory bred sand fly females established from a local population of Lutzomyia longipalpis. All three rodent species developed disseminated subclinical parasitological infections, but clinical signs (lesions) were transient and self-resolving. N. squamipes, N. lasiurus and R. rattus were all infectious when asymptomatic, though their competence in transmission potential appears to differ with R. rattus showing signs of lower susceptibility. These results provide further evidence that a multi-host reservoir is responsible for maintaining transmission with a bridge between infectious sylvatic and peridomestic rodent populations.

Host-biting rate and susceptibility of some suspected vectors to Leishmania braziliensis

BACKGROUND

American tegumentary leishmaniasis is a serious Brazilian public health problem. This diseases is attributed to seven species of Leishmania, however, the majority of cases are associated with Leishmania braziliensis. Some phlebotomine species have been implicated in the transmission of this parasite, nonetheless only Psychodopygus wellcomei has had its vectorial competence demonstrated. Thus this study sought to assess some parameters related to the vectorial capacity of anthropophilic species of sand fly occurring in São Paulo state: Pintomyia fischeri, Migonemyia migonei Nyssomyia intermedia, Nyssomyia whitmani, Expapillata firmatoi and Psychodopygus ayrozai, under laboratory conditions. These parameters were the duration of the gonotrophic cycle, proportion of females which feed on hamster, the rate of infection by L. braziliensis and the duration of the extrinsic incubation period.

METHODS

The sandflies were collected in three regions of the São Paulo state: Greater São Paulo and the Mogi Guaçu and Iporanga municipalities. To assess the proportion of engorged females the insects were fed on hamsters to estimate the duration of the gonotrophic cycle. To estimate the susceptibility to infection of each species, their females were fed on hamsters infected with Leishmania braziliensis and dissected to ascertain the localization of the flagellates and estimate the extrinsic incubation period.

RESULTS

Low hamster attractiveness to Ps. ayrozai was observed. A high proportion of engorged females was observed when the hamster had its whole body exposed. The gonotrophic cycle ranged between three and eight days. Mg. migonei, Pi. fischeri, Ny. neivai, Ny. intermedia, Ny. whitmani and Ex.firmatoi presented susceptibility to infection by L. braziliensis. The highest infection rate (34.4%) was observed for Ny. whitmani and the lowest for Ny. intermedia (6.6%). Mg. migonei presented late-stage infection forms on the fifth day after feeding, but in the other species these forms were observed as from the fourth day.

CONCLUSIONS

Our results, together with other parameters of their behavior under natural conditions, suggest the potential role of Ex. firmatoi as vector of this parasite and reinforce that of Mg. migonei, Pi. fischeri, Ny. neivai, Ny. intermedia and Ny. whitmani in the areas in which they occur.

Ecology of phlebotomines (Diptera: Psychodidae) in a transitional area between the Amazon and the Cerrado in the State of Maranhão, Brazil

The Amazon rainforest and the Brazilian Cerrado both possess high phlebotomine diversity. The fragmentation of these habitats has resulted in the appearance of human cases of cutaneous leishmaniasis. In one altered area of mixed primary vegetation (forest and Cerrado) and its adjacent settlement in the northeast state of Maranhão, Brazil, evidence exists for the active transmission of cutaneous leishmaniasis. Accordingly, an entomological investigation was performed in both the forest and the settlement to compare the phlebotomine vector faunain each environment. The study was conducted from September 2009 to August 2010 in the municipality of Itapecuru Mirim in the state of Maranhão, Brazil. The phlebotomine species were captured using 24 light Center for Disease Control and Prevention traps that were placed in the forest and the settlement (peridomicile and intradomicile). The similarity between the phlebotomine compositions in the forest and those in the settlement was determined using a Principal Coordinate Analysis based on a dissimilarity matrix that was calculated using the Bray-Curtis index (relative abundance) and the Jaccard index (presence and absence of species). In total, 29 Lutzomyia species and one Brumptomyia species were collected. The phlebotomines were diverse and abundant in both the forest fragment (27 species, 4,606 specimens) and the settlement (22 species, 753 specimens). The most abundant species were L. infraspinosa (25%), L. davisi (21%), L. antunesi (21%), L. longipalpis (9%), L. saulensis (6%), L. flaviscutellata (5%), and L. wellcomei (4%). Some species were found strictly in the forest, other species were exclusive to the anthropic environment, and some species colonized both of the studied environments. The phlebotomines adaptation to these modified environments explains the autochthonous outbreak of cutaneous leishmaniasis.

Species diversity of sandflies (Diptera: Psychodidae) during different seasons and in different environments in the district of Taquaruçú, state of Tocantins, Brazil

Phlebotomine sandflies are the vectors for the protozoan parasites that cause leishmaniasis. The present study investigated the species composition of sandfly fauna in the rural district of Taquaruçú, municipality of Palmas, state of Tocantins, Brazil and compared the diversity of species among intradomicile, peridomicile and forest environments during the dry and rainy seasons. Sandflies were collected using CDC light traps over the course of three months during the dry and rainy seasons. A total of 767 specimens were captured, belonging to different 32 species. The most abundant species were Micropygomyia goiana (Martins, Falcão & Silva), Sciopemyia sordellii (Shannon & Del Ponte), Evandromyia carmelinoi (Ryan Fraiha, Lainson & Shaw), Evandromyia termitophila (Martins, Falcão & Silva), Nyssomyia whitmani (Antunes & Coutinho) and Lutzomyia longipalpis (Lutz & Neiva). The highest species diversity (30) and the greatest percentage of specimens (78.3%) were obtained during the rainy season. During the dry season, the species richness and abundance were greater in domestic environments. However, during the rainy season, the forest displayed the highest species richness and the domestic environment exhibited the greatest species abundance. Several important vector species are reported in this study.

The aetiological agents of American cutaneous leishmaniasis in the municipality of Monte Negro, Rondônia state, western Amazonia, Brazil

Although American cutaneous leishmaniasis (ACL) is one of the most important endemic diseases in the Brazilian state of Rondônia, there is very little information on the species of parasite involved. The objective of the present study was to identify the Leishmania species causing ACL in the Monte Negro municipality of the state. Over a 6-year period (1997-2002), the skin lesions of 233 patients were examined while the patients were attending an outpatients' clinic at the University of São Paulo's Advanced Research Unit in Monte Negro. ACL was diagnosed in 137 (58.8%) of the patients and leishmanial parasites were successfully isolated from 14 of the ACL cases. Using a panel of 24 monoclonal antibodies, 12 of the 14 isolates were identified, as L. (Viannia) braziliensis (seven), L. (V.) lainsoni (one), a L. (V.) lainsoni-like species (two), a L. (V.) guyanensis-like species (one), or a L. (Viannia) species that was different from all named species (one). These are the first records of human infection with L. (V.) braziliensis and L. (V.) lainsoni in Rondônia.

Abundance of Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae) and urban transmission of visceral leishmaniasis in Campo Grande, state of Mato Grosso do Sul, Brazil

The outspread and urbanization of visceral leishmaniasis (VL) in Campo Grande, state of Mato Grosso do Sul, lead us to undertake the present study over diversity and abundance of sand flies in the urban area to compare with previous search carried out during 1999/2000, before the identification of the disease in the human population. The captures were carried out with automatic light traps, weekly, from February 2004 to February 2005 on three sites including a forested area (Zé Pereira), two peridomicilies (shelters of domestic animals and cultivation areas), and intradomicilie. In the present study 110 collections were obtained during 13 months for 1320 h of collections, resulting in 5004 specimens, 3649 males and 1355 females belonging to the 20 following species: Brumptomyia avellari, Brumptomyia sp., Bichromomyia flaviscutellata, Evandromyia lenti, E. termitophila, E. cortelezzii, E. borrouli, Lutzomyia sp., L. longipalpis, Micropygomyia quinquefer, N. antunesi, N. whitmani, Pintomyia christenseni, Pi. damascenoi, Psathyromyia aragaoi, Ps. campograndensis, Ps. hermanlenti, Ps. shannoni, Pychodopygus claustrei, and Sciopemyia sordellii. L. longipalpis was the most abundant species in the anthropic environment with 92.22% of the captures. This shows an increase of sixty times in the density of L. longipalpis compared to the last sand fly evaluation in 1999/2000. The high density of L. longipalpis in Campo Grande is the main factor of risk in transmission of the disease to human in the urban area. The capture of N. antunesi, typical specie from Amazonian region, in Mato Grosso do Sul is reported for the first time.

Dinâmica espaço-temporal de flebotomíneos (Diptera, Psychodidae) do município de Santa Quitéria, área de cerrado do Estado do Maranhão, Brasil

A flutuação sazonal, a freqüência horária e a ocorrência dos flebotomíneos nos ambientes intradomiciliar, peridomiciliar e extradomiciliar (cerrado), no município de Santa Quitéria, Estado do Maranhão foram estudados. Os espécimes foram capturados entre 18 e 6 horas, de maio de 1999 a abril de 2000, com armadilhas luminosas tipo CDC. Foram coletados 4.880 espécimes de 11 espécies. A riqueza e abundância foram maiores no peridomicílio (11 espécies; 50,1% dos espécimes), seguido pelo intradomicílio (9 espécies, 34%) e cerrado (7 espécies, 15,8%). Duas espécies foram encontradas na estação chuvosa, uma na estiagem e oito em ambas estações. Na estiagem foram registradas elevadas freqüências de Lutzomyia longipalpis Lutz & Neiva, 1912 (88,4%), L. evandroi Costa Lima & Antunes, 1936 (83,6%), L. lenti Mangabeira, 1938 (86%) e L. shannoni Dyar, 1929 (100%), enquanto as freqüências de L. quinquefer Dyar, 1929 (100%) e L. whitmani Antunes & Coutinho, 1939 (75%) foram maiores no período chuvoso. Os flebotomíneos foram encontrados a noite inteira, mas os horários de maior freqüência variaram de acordo com a espécie, observando-se picos no crepúsculo vespertino e primeiras horas da noite: L. quinquefer (18 h - 19 h); L. goiana Martins, Falcão & Silva, 1962 (18 h - 21 h); L. whitmani (19 h - 21 h) e L. longipalpis (20 h - 21 h) e ao longo da noite e no crepúsculo matutino: L. evandroi (21 h - 23 h e 3 h - 5 h), L. longipalpis (1 h - 3 h), L. lenti (22 h - 23 h e 4 h - 5 h). A ocorrência dos flebotomíneos nos diferentes ambientes, horários e estações vem sendo acompanhada por notificações de vários casos de leishmanioses cutânea e visceral.

Lutzomyia longipalpis and the eco-epidemiology of American visceral leishmaniasis, with particular reference to Brazil: a review

An historical review is given of American visceral leishmaniasis (AVL), with particular reference to the eco-epidemiology of the disease in Brazil. Following the first records of AVL in this country, in 1934, the sandfly Lutzomyia longipalpis (Lutz and Neiva, 1912) was incriminated as the principal vector. It is now generally accepted, however, that there exist a number of cryptic species under the name of Lu. longipalpis s.l. and that variations in the quantity of the vasodilatory peptide maxadilan in the saliva of flies from different populations of Lu. longipalpis s.l., may account for the variable clinical manifestations of AVL seen in different geographic regions. Distribution of AVL has been shown to extend throughout most of South and Central America, with the domestic dog serving as the principal reservoir of infection for man. However, while one hypothesis suggests that the causative parasite is Leishmania infantum, imported from Europe with the Portuguese and Spanish colonists, the demonstration of a high rate of benign, inapparent infection in foxes in Amazonian Brazil raised an opposing suggestion that the parasite is indigenous to the Americas. Recent reports of similar infections in native marsupials, and possibly rodents, tend to support this view, particularly as Lu. longipalpis is primordially a silvatic sandfly. Although effective control measures in foci of the disease will diminish the number of canine and human infections, the presence of such an enzootic in a variety of native animals will render the total eradication of AVL unlikely.

Genetic polymorphism and molecular epidemiology of Leishmania (Viannia) braziliensis from different hosts and geographic areas in Brazil

Numerical zymotaxonomy and variability of the internal transcribed spacers (ITS) between the small and large subunits of the rRNA genes were used to examine strain variation and relationships in natural populations of Leishmania (Viannia) braziliensis. A total of 101 strains from distinct hosts and Brazilian geographic regions were assigned to 15 zymodemes clustered in two major genetic groups. The great number of isolates (48.5%) placed in zymodeme IOC/Z-27 were collected on the Atlantic coast. The high molecular diversity found in populations in the Amazon Basin was related to the great number of sandfly vector(s) in that region. The results of the restriction fragment length polymorphism analysis of the ITS depicted considerable intraspecific variation. Genotypic groups A, B, and C contained 39, 40, and 22 isolates, which were divided into 16, 10, and 15 genotypes, respectively. The genetic polymorphism observed demonstrates the degree of diversity of L. (V.) braziliensis strains from different regions where they are endemic. The results reinforce the clonal theory for Leishmania parasites showing the genetic diversity of this pathogen and an association of L. (V.) braziliensis genotypes with specific transmission cycles, probably reflecting an adaptation of different clones to the vector species involved.

Genetic variation in populations of Leishmania species in Brazil

The population structure of strains of Leishmania (Viannia) braziliensis sensu lato from Pará State and Paraná State in Brazil, of L. (V.) shawi and L. (Leishmania) amazonensis from Pará State, and the relationships of type strains of the subgenera L. (Viannia) and L. (Leishmania) were examined by the random-amplified polymorphic deoxyribonucleic acid (RAPD) technique. Four different primers (M13-40, QG1, L15996 and delta gt11R) were used. The bands were analysed using the neighbor-joining (NJ) and unweighted pair-group method with arithmetic averages (UPGMA) algorithms of the MEGA package. The topology of the NJ and UPGMA trees was very similar but they were not always identical. Both trees differentiated the standard strains of the different species. Strains from the same location were grouped together only in the UPGMA phenogram of the M13-40 primer. L. (V.) braziliensis isolates from Paraná State were genetically closer to those from Paragominas, Pará State than to those from the Amazonian regions of Carajás in Pará State and Peru. The relationship was not dependent on geographical distance. It is postulated that the groups arose from different origins, in which the Amazonian stocks were related to Psychodopygus sand flies while the Paraná strains originated from a gene pool transmitted by Lutzomyia sand flies such as Lutzomyia (Nyssomyia) whitmani. Transmission by Ps. complexus in Paragominas is considered to be a secondary adaptation from the Lutzomyia leishmanial gene pool. Although the vectors of L. (V.) braziliensis are poorly known in the Amazon region, there is strong evidence that the major vectors are all Psychodopygus spp. There was a high degree of genetic variability amongst the L. (V.) shawi strains and there was no clear grouping according to the strains' origins. The genetic variability amongst L. (L.) amazonensis strains from the same locations was much lower but they formed 2 groups which coincided with their origin. Our results support the clonal population structure of Leishmania isolates and suggest that their distribution is related to the origin of the gene pool as well as to present vector and reservoir movements.

Some Psychodidae (Diptera) from Atlantic forest in south-eastern Brazil, with descriptions of Trichomyia dolichopogon sp. nov. and Trichomyia riodocensis sp. nov

The family Psychodidae includes the medically important phlebotomine sand flies and four other subfamilies that have been little studied in the Neotropics. The authors here report the results of a trip to collect psychodids in Parque Estadual do Rio Doce, a national park in Minas Gerais that contains one of the largest surviving areas of Atlantic Forest in Brazil. Collections made by Malaise and CDC light traps as well as from diurnal resting sites included 15 species of Psychodinae and Trichomyiinae, among them Trichomyia dolichopogon sp. nov., T. riodocensis sp. nov. and 13 other species new to science but represented by females only. Twelve species of phlebotomine sand flies (Lutzomyia spp.) were also collected. Collections from an undisturbed area of the park were much richer faunistically than those from an area that was destroyed by fire in 1967 but had since regenerated, suggesting that recovery after environmental disturbances of this type may be prolonged. This pattern was not seen for phlebotomine sand flies, whose greater abundance and species richness in the disturbed section of the park may be related to their dependence on small mammal hosts, known to be more diverse in this type of habitat.

[Phlebotomine sand flies in the State of Tocantins, Brazil (Diptera: Psychodidae)]

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.

[Study of the vectorial competence of Lutzomyia intermedia (Lutz & Neiva, 1912) for Leishmania (Viannia) braziliensis, Vianna, 1911]

This paper investigated the vectorial competence of Lutzomyia intermedia (Diptera: Psychodidae) in Vale do Ribeira (SP) to strains of Leishmania (Viannia) braziliensis (Kinetoplastida: Trypanosomatidae), by means of a search for natural infection; exposure of wild and colonized females (F1) to the lesions of experimentally infected hamsters and transmission tests by bite. The natural infection and the transmission tests were negative. In the exposures of Lu. intermedia to infected lesions we found rates of 74% (123+/166 dissected) and 70% (115+/164 dissected) for the wild and colonized females respectively. The development of the parasites was compatible with the development model of Peripilaria. The susceptibility of the tested strains associated with the epidemiological indicators contribute to the vectorial role suspicion of Lutzomyia intermedia in the studied region.

Leishmaniose tegumentar americana em centro de treinamento militar localizado na Zona da Mata de Pernambuco, Brasil

Um surto de leishmaniose tegumentar americana ocorreu em 1996 em unidade de treinamento militar situada na Zona da Mata de Pernambuco, com o registro de 26 casos humanos. Um inquérito epidemiológico foi realizado através da realização de levantamento entomológico e da aplicação do Teste de Montenegro. Lutzomyia choti apresentou predominância de 89,9% dos flebótomos identificados. De 545 homens que participaram de treinamentos no período, 24,1% (incluindo os casos clínicos) foram positivo para o Teste de Montenegro.

Species-specific detection of Leishmania in sandflies using an enzyme-linked immunosorbent assay

A direct enzyme-linked immunosorbent assay (ELISA) using species-specific monoclonal antibodies was developed for the detection and identification of Leishmania in sandflies. A titration of mock-infected Phlebotomus papatasi showed that fewer than 2000 L. major promastigotes could be detected. The percentage of infected P. papatasi collected in the field, as determined by dissection, was compared to that revealed by the ELISA. Both methods gave similar results, irrespective of whether the flies were caught by sticky papers or light-traps. The percentage of infected flies determined by either method was also similar in experimentally infected colony reared sandflies. The ELISA can be carried out using multiple species-specific antibodies, and is as accurate as identification of infected sandflies by microscopical examination. The technique should be useful for identifying sandfly species involved in transmitting different species of Leishmania, and for rapid assessment of leishmanial infection rates in endemic regions.

Psychodopygus complexus, a new vector of Leishmania braziliensis to humans in Pará State, Brazil

This paper reports the finding of 4 specimens of Psychodopygus complexus, captured in the Paragominas region of Pará State, Brazil, naturally infected with trypanosomatids that were positively identified as Leishmania (Viannia) braziliensis. Attention is drawn to the importance of this species as a vector since it is highly anthropophilic and has a very extensive geographical distribution in the lower Amazon region of Pará State south of the Amazon river, including the island of Marajó.

Leishmaniasis in Brazil: XXIII. The identification of Leishmania braziliensis braziliensis in wild-caught neotropical sandflies using monoclonal antibodies

Using the indirect immunofluorescence test natural flagellate infections of wild-caught sandflies, from the Serra dos Carajás region of Pará State, Brazil, were identified by sequentially staining smears made from the infected flies with monoclonal antibodies. With normal methods of isolation 30% of the infections were identifiable, but when monoclonal antibodies specific to Leishmania braziliensis braziliensis were used a further 26% were identified. The staining of organisms in smears of natural infections was different from that seen with culture forms and with forms from experimentally infected wild flies. A monoclonal antibody previously thought to be specific for Leishmania did not react with culture forms of Endotrypanum, but did react with those of monoxenous insect parasites.