Leishmaniasis in Brazil. VI. Observations on the seasonal variations of Lutzomyia flaviscutellata in different types of forest and its relationship to enzootic rodent leishmaniasis (Leishmania mexicana amazonensis)

Phlebotominae (Diptera: Psychodidae) and Biomes in the State of Mato Grosso do Sul, Brazil

The state of Mato Grosso do Sul, Brazil is an important region of South America regarding leishmaniasis, with the great diversity of sandflies reported since 1938 and wide biodiversity represented by its biomes (Atlantic Forest, Cerrado, and Pantanal). A checklist of sandflies is presented here for the state and respective biomes. The data base was compiled from primary and secondary data. The primary data collection involved automatic light traps at Miranda-Abobral Pantanal subregion and in subregion Baixa Nhecolância of Pantanal. The secondary data were obtained from entomology scientific collections and a literature review of articles from 1938 to 2019, including entomological museum collections. A total of 71 species were reported, belonging to 14 genera and 13 subgenera, in 61 municipalities of the state, including the type locality of 9 species, and the first report of Lutzomyia cruzi (Mangabeira 1938), vector of Leishmania infantum (Nicolle 1937), in the Pantanal region of Miranda-Abobral. Other vector species, Bichromomyia flaviscutellata (Mangabeira 1942), Lutzomyia longipalpis (Lutz & Neiva 1912), Nyssomyia antunesi (Coutinho 1939), Nyssomyia intermedia (Lutz & Neiva 1912), Nyssomyia neivai (Pinto 1926), and Nyssomyia whitmani (Antunes & Coutinho 1939), are reported in the entire area of the state. Maps containing the distribution of sandflies on Mato Grosso do Sul biomes were produced. The eclecticism of the species in relation to their ecotypes was observed, with several species using the three biome types as habitats and breeding sites.

Natural Leishmania (Leishmania) mexicana infection and biting activity of anthropophilic sand fly Lutzomyia ayacuchensis in the Ecuadorian Andes

To elucidate the transmission mode of Andean cutaneous leishmaniasis (Andean-CL), natural Leishmania infection and biting activity of sand flies were tested in a selected sylvatic focus of the endemic area of the Ecuadorian Andes. Monthly sand fly collections and dissections were conducted during 12 months from July 2018 to June 2019. The Leishmania positive specimens/slides with innumerable amounts of actively mobile flagellates made us easy to detect positive sand flies. The promastigotes observed located in the anterior and posterior midgut, without the hindgut localization. The parasite isolated was identified as L. (L.) mexicana by cytochrome b gene analysis. No other Leishmania or flagellate species parasitic in sand flies was observed in the area. Only Lu. ayacuchensis was caught throughout. Monthly microscopic examination of Lu. ayacuchensis revealed 0.75-8.33% of natural L. (L.) mexicana infection rates. Higher Leishmania infection months were present at the end of the wet season of the Andes, while higher sand fly numbers occurred during the dry season. Diurnal biting (blood meal seeking) activity of sand flies started around 17:30 before sunset, increased between 18:00 and 19:30, and thereafter decreased drastically probably because of low temperature (15-18 °C) in the area. The results provide information important for the planning of vector control strategy and management of the disease in the Andean-CL endemic area of Ecuador.

Leishmania DNA detection and species characterization within phlebotomines (Diptera: Psychodidae) from a peridomicile-forest gradient in an Amazonian/Guianan bordering area

In the border region between Brazil and French Guiana, American cutaneous leishmaniasis is a worrisome public health issue, and entomological studies are required there to better identify classical and putative emerging transmission patterns. The present study aimed to detect and characterize Leishmania DNA in the phlebotomine population of Oiapoque (Amapá State, Brazil). Phlebotomines were captured in anthropized and wild environments in the outskirts of Oiapoque municipality, using CDC light traps installed in vertical (ground/canopy level) and horizontal (peridomicile/extradomicile/forest-edge/forest) strata. Captured specimens were identified according to their morphology. Females were processed for Leishmania DNA detection and characterization using a multiplex polymerase chain reaction targeting kinetoplast DNA (kDNA) and the phlebotomine cacophony gene. The kDNA positive samples were characterized by cloning and sequencing the Leishmania 234 bp-hsp70 gene. Among the 3957 phlebotomine specimens captured, 26 pooled female samples were positive for Leishmania (Viannia) spp. DNA. Sequencing analysis allowed species-specific identification of L. (V.) braziliensis DNA in Trichophoromyia ininii, Bichromomyia flaviscutellata, Nyssomyia umbratilis, and Evandromyia infraspinosa, and L. (V.) guyanensis DNA in Ny. umbratilis. A pooled sample of Ny. umbratilis was positive for both L. (V.) braziliensis and L. (V.) guyanensis DNA. The present study provided additional information regarding ACL ecology in Oiapoque, highlighting the presence of L. (V.) braziliensis DNA in different phlebotomine species. The epidemiological implications of these findings and the determinant incrimination of L. (V.) braziliensis as proven vectors in that region must be clarified. In this regard, studies on Leishmania spp. infection and suggestive anthropophilic behavior of associated phlebotomines need to be prioritized in entomological surveillance.

Workshop no. 11. Ecology of Leishmania

The ecology of Leishmania of man is concerned with the circulation of the parasite in nature from one mammal to another by the bite of phlebotomine sandflies. The natural vertebrate hosts are anthropocentrieally referred to as reservoir hosts although in sorac foci of human leishmaniasis (anthroponotic cutaneous leishmaniasis and Indian kala-azar) man himself is thought to be the reservoir.

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.

Phlebotomine Sand Fly Composition (Diptera: Psychodidae) and Putative Vectors of American Cutaneous Leishmaniasis in Porto Velho Municipality, Western Amazon, Brazil

This study evaluated the species composition of sand flies and identified potential vectors of Leishmania Ross species in rural areas of Porto Velho, Rondônia State, Brazil. American cutaneous leishmaniasis (ACL) is one of the gravest threats to public health in this state. Sand flies were collected over the course of 2014 and 2015 using HP light traps. Polymerase chain reaction was performed by targeting the Leishmania mkDNA region. In total, 2,344 sand flies were collected, from which 45 species, nine subgenera, and five species group were identified. The most abundant species were Lutzomyia antunesi (Coutinho) (n = 597, 25.47%), Lutzomyia ubiquitalis (Mangabeira) (n = 496, 21.16%), and Lutzomyia octavioi (Vargas) (n = 199, 8.49%). The greatest diversity occurred in the forest environment where the most abundant species were L. antunesi (n = 588, 25.07%), L. ubiquitalis (n = 493, 21.02%), L. octavioi (n = 199, 8.49%), and Lutzomyia flaviscutellata (Mangabeira) (n = 132, 5.63%). Two pools of L. ubiquitalis were positive for Leishmania DNA, which suggests that L. ubiquitalis is a putative vector of leishmaniasis in the municipality of Porto Velho.

Leishmania in synanthropic rodents (Rattus rattus): new evidence for the urbanization of Leishmania (Leishmania) amazonensis

This study aimed to detect parasites from Leishmania genus, to determine the prevalence of anti-Leishmania spp. antibodies, to identify circulating species of the parasite, and to determine epidemiological variables associated with infection in rats caught in urban area of Londrina, Paraná, Brazil. Animal capture was carried out from May to December 2006, serological and molecular methods were performed. DNA was extracted from total blood, and nested-PCR, targeting SSu rRNA from Leishmania genus, was performed in triplicate. The positive samples were sequenced twice by Sanger method to species determination. In total, 181 rodents were captured, all were identified as Rattus rattus and none showed clinical alterations. Forty-one of the 176 (23.3%) animals were positive for Leishmania by ELISA and 6/181 (3.3%) were positive by IFAT. Nine of 127 tested animals (7.1%) were positive by PCR; seven were identified as L. (L.) amazonensis, one as L. (L.) infantum. Four rats were positive using more than one test. This was the first description of synanthropic rodents naturally infected by L. (L.) amazonensis (in the world) and by L. (L.) infantum (in South Brazil). Regarding L. (L.) amazonensis, this finding provides new evidence of the urbanization of this etiological agent.

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.

An Evaluation of Light-Emitting Diode (LED) Traps at Capturing Phlebotomine Sand Flies (Diptera: Psychodidae) in a Livestock Area in Brazil

A study to evaluate the use of light-emitting diodes (LEDs) as an attractant for phlebotomine sand flies at two animal pens in a livestock area in Brazil was performed. Light-suction traps were operated overnight with the following light sources: green, blue, and incandescent (control) lights. In total, 22 individual collections were made at each site and 44 with each trap type. In total, 2,542 specimens belonging to 14 phlebotomine species were collected. The most abundant species in the light traps were Nyssomyia whitmani, Evandromyia evandroi, Micropygomyia goiana, Lutzomyia longipalpis, and Bichromomyia flaviscutellata Taking the two sites together, the green-LED light was the most attractive, followed by the blue and incandescent lights, and the difference between the green-LED and the control was statistically significant. Most species were green-biased at both sites, but some species-specific differences were observed. However, even with these differences, the standard incandescent light was outcompeted by LEDs. The green-LED-biased response observed in the present study, together with numerous advantages in favor of LEDs, suggests that the green-LED light source can be used as an effective substitute for the currently used incandescent bulb in monitoring traps for phlebotomine sand flies in Brazil.

Ecological Niche Modelling Predicts Southward Expansion of Lutzomyia (Nyssomyia) flaviscutellata (Diptera: Psychodidae: Phlebotominae), Vector of Leishmania (Leishmania) amazonensis in South America, under Climate Change

Vector borne diseases are susceptible to climate change because distributions and densities of many vectors are climate driven. The Amazon region is endemic for cutaneous leishmaniasis and is predicted to be severely impacted by climate change. Recent records suggest that the distributions of Lutzomyia (Nyssomyia) flaviscutellata and the parasite it transmits, Leishmania (Leishmania) amazonensis, are expanding southward, possibly due to climate change, and sometimes associated with new human infection cases. We define the vector's climatic niche and explore future projections under climate change scenarios. Vector occurrence records were compiled from the literature, museum collections and Brazilian Health Departments. Six bioclimatic variables were used as predictors in six ecological niche model algorithms (BIOCLIM, DOMAIN, MaxEnt, GARP, logistic regression and Random Forest). Projections for 2050 used 17 general circulation models in two greenhouse gas representative concentration pathways: "stabilization" and "high increase". Ensemble models and consensus maps were produced by overlapping binary predictions. Final model outputs showed good performance and significance. The use of species absence data substantially improved model performance. Currently, L. flaviscutellata is widely distributed in the Amazon region, with records in the Atlantic Forest and savannah regions of Central Brazil. Future projections indicate expansion of the climatically suitable area for the vector in both scenarios, towards higher latitudes and elevations. L. flaviscutellata is likely to find increasingly suitable conditions for its expansion into areas where human population size and density are much larger than they are in its current locations. If environmental conditions change as predicted, the range of the vector is likely to expand to southeastern and central-southern Brazil, eastern Paraguay and further into the Amazonian areas of Bolivia, Peru, Ecuador, Colombia and Venezuela. These areas will only become endemic for L. amazonensis, however, if they have competent reservoir hosts and transmission dynamics matching those in the Amazon region.

Phlebotomine sandflies (Diptera: Psychodidae) of the Atlantic forest in Recife, Pernambuco state, Brazil: the species coming to human bait, and their seasonal and monthly variations over a 2-year period

In a study of the phlebotomine sandflies (Diptera: Psychodidae) in a forest reserve in Recife, Pernambuco state, north-eastern Brazil, the sandflies landing on human bait between 1.00 and 1.42 h after sunset were collected weekly for 2 years. Although 10,287 sandflies of 10 Lutzomyia species were collected, almost all (96.5%) of the sandflies caught were Lu. umbratilis. This species and several others caught are potential vectors of some of the Leishmania parasites that cause human disease. The recorded landing rate for Lu. umbratilis peaked, at the high level of 333.3 flies/person-hour, during the collections made in May 2003.The relative rarity in the collections of males of some of the species caught probably indicates that these species do not lek on their bloodmeal sources. It is likely that the sizes of the local populations of species that are not very anthrophilic, such as Lu. flaviscutellata, are much larger than indicated by the collections made on human bait.

Ecological aspects of phlebotomines (Diptera: Psychodidae) in endemic area of visceral leishmaniasis, Campo Grande, State of Mato Grosso do Sul, Brazil

Aspects of phlebotomine behavior were investigated in the city of Campo Grande, Mato Grosso do Sul state. The insects were captured weekly during December 2003 to November 2005, with Centers for Disease Control light traps at seven different sites including forests and residential areas. In total, 11,024 specimens (7,805 males and 3,219 females) were collected, from which 9,963 (90.38%) were identified as Lutzomyia longipalpis, the proven vector of American visceral leishmaniasis agent. The remaining 9.62% comprised 21 species. L. longipalpis was the most frequent species in all sampled sites, and the first in the ranking of standardized species abundance index. In residential areas this species clearly predominated in the peridomicile (90.96%), in contrast to the intradomicile (9.04%); in animal shelters, it was more numerous in hen houses and prevailed at ground level, inside, and at forest edge around the residences; this aspect is worrying because this insect may remain sheltered in forested environments during the use of insecticides in homes. In the forest environment, other probable or proven vector of cutaneous leishmaniasis agents were also captured such as Lutzomyia whitmani (=Nyssomyia whitmani, sensu Galati), Lutzomyia antunesi (=Nyssomyia antunesi, sensu Galati), and Lutzomyia flaviscutellata (=Bichromomyia flaviscutellata, sensu Galati).

Sand fly captures with Disney traps in area of occurrence of Leishmania (Leishmania) amazonensis in the state of Mato Grosso do Sul, mid-western Brazil

INTRODUCTION: The work was conducted to study phlebotomine fauna (Diptera: Psychodidae) and aspects of American cutaneous leishmaniasis transmission in a forested area where Leishmania (Leishmania) amazonensis occurs, situated in the municipality of Bela Vista, State of Mato Grosso do Sul, Brazil. METHODS: The captures were conducted with modified Disney traps, using hamster (Mesocricetus auratus) as bait, from May 2004 to January 2006. RESULTS: Ten species of phlebotomine sandflies were captured: Brumptomyia avellari, Brumptomyia brumpti, Bichromomyia flaviscutellata, Evandromyia bourrouli, Evandromyia lenti, Lutzomyia longipalpis, Psathyromyia campograndensis, Psathyromyia punctigeniculata, Psathyromyia shannoni and Sciopemyia sordellii. The two predominant species were Ev bourrouli (57.3%) and Bi flaviscutellata (41.4%), present at all sampling sites. Two of the 36 hamsters used as bait presented natural infection with Leishmania. The parasite was identified as Leishmania (Leishmania) amazonensis. CONCLUSIONS: Analysis of the results revealed the efficiency of Disney traps for capturing Bichromomyia flaviscutellata and the simultaneous presence of both vector and the Leishmania species transmitted by the same can be considered a predictive factor of the occurrence of leishmaniasis outbreaks for the human population that occupies the location.

Fauna de flebotomíneos (Diptera: Psychodidae) de uma reserva de campina no Estado do Amazonas, e sua importância epidemiológica

INTRODUÇÃO: No Brasil, a maior diversidade de flebotomíneos é encontrada na Região Amazônica, principalmente em floresta primária de terra-firme. No entanto, sua fauna ainda é pouco conhecida em outros ecossistemas desta região. MÉTODOS: a fim de conhecer a fauna de flebotomíneos de outro ecossistema amazônico, coletas com armadilhas de luz CDC foram realizadas em uma área de campina/campinarana na zona periurbana da Cidade de Manaus. RESULTADOS: foram capturados 814 flebotomíneos de 26 espécies, sendo as mais abundantes: Lutzomyia flaviscutellata (64,5%); Lutzomyia georgii (14%); Lutzomyia olmeca nociva (8,1%); Lutzomyia furcata (3,2%); Lutzomyia monstruosa (1,3%); Lutzomyia umbratilis (1,1%) outros (7,8%). CONCLUSÕES: Campina/campinarana revelou-se de grande importância epidemiológica devido a elevada abundância de Lutzomyia flaviscutellata e Lutzomyia olmeca nociva, ambas vetoras de Leishmania (Leishmania) amazonensis. Com base nestas informações, será possível traçar metas para estudos parasitológicos e conscientizar pesquisadores e estudantes, que mantém constante exposição nesta área realizando trabalhos de pesquisa, sobre o possível risco de contaminação por Leishmania.

Sampling methods for phlebotomine sandflies

A review is presented of methods for sampling phlebotomine sandflies (Diptera: Psychodidae). Among approximately 500 species of Phlebotominae so far described, mostly in the New World genus Lutzomyia and the Old World genus Phlebotomus, about 10% are known vectors of Leishmania parasites or other pathogens. Despite being small and fragile, sandflies have a wide geographical range with species occupying a considerable diversity of ecotopes and habitats, from deserts to humid forests, so that suitable methods for collecting them are influenced by environmental conditions where they are sought. Because immature phlebotomines occupy obscure terrestrial habitats, it is difficult to find their breeding sites. Therefore, most trapping methods and sampling procedures focus on sandfly adults, whether resting or active. The diurnal resting sites of adult sandflies include tree holes, buttress roots, rock crevices, houses, animal shelters and burrows, from which they may be aspirated directly or trapped after being disturbed. Sandflies can be collected during their periods of activity by interception traps, or by using attractants such as bait animals, CO2 or light. The method of trapping used should: (a) be suited to the habitat and area to be surveyed, (b) take into account the segment of the sandfly population to be sampled (species, sex and reproduction condition) and (c) yield specimens of appropriate condition for the study objectives (e.g. identification of species present, population genetics or vector implication). Methods for preservation and transportation of sandflies to the laboratory also depend on the objectives of a particular study and are described accordingly.

Distribution of sandflies (Diptera:Psychodidae) on tree-trunks in a non-flooded area of the Ducke Forest Reserve, Manaus, AM, Brazil

Sandflies were collected in the base of tree-trunks in the seasons of high and least rainfall in the Ducke Forest Reserve, near Manaus in the State of Amazonas. Lutzomyia umbratilis was the most abundant sandfly species. Caryocar villosum, Chrysophyllum amazonicum, Dinizia excelsa, Eschweilera atropetiolata and Parkia multijuga were the tree species on which most sandflies were collected and relative abundance were related to trunk characteristics. Seasonal patterns of sandfly distribution in the forest were observed.

[Phlebotomines (Diptera: Psychodidae) focusing visceral leishmaniasis in the State of Mato Grosso do Sul, Brazil]

INTRODUCTION

In the Americas, Lutzomyia longipalpis has been incriminated as the vector of visceral leishmaniasis in almost all the areas in which this disease has been reported. The notification of human cases of visceral leishmaniasis and the presence of dogs with an appearance suggestive of the disease in the country of Corumbá, Mato Grosso do Sul State, Brazil, led us to undertake an entomological investigation in this area, for the purpose of identifying the phlebotomine vector.

MATERIAL AND METHOD

The county of Corumbá is located in the Pantanal region and its urban area is situated at 18 degrees 59' 44" South and 57 degrees 39' 16" West. The research project was carried out in peri and intradomiciliary environments, in three urban districts, one of which was central and the other two on the outskirts, and in a cave situated outside the urban perimeter. Most of the captures were made weekly with light automatic traps, in the period from February 1984 to December 1986. Meteorological data for this period were obtained from the city's meteorological station and those for the period from 1925 to 1982 from the literature.

RESULTS

The urban phlebotomine fauna consisted of eight species and was similar to that of the cave, except that in the latter the species were more abundant. Lutzomyia cruzi was predominant in the peri and intradomiciliary environments. Its prevalence in the central district was of 90.3% and lower in the outskirts. Lu. forattinii presented considerable prevalence (39.0%) in one of the outlying districts too. In the cave, Lu. corumbaensis was the predominant species, followed by Lu. sordellii, Lu. forattinii, Lu. peresi and Lu. cruzi. The impact of the climatic condition and the action of insecticides in the urban area on the frequency of the species, as well as the use of the cave as a breeding ground by the phlebotomines, in view of the changes in the sex rate, are commented. Data on anthropophily and captures of Lu. forattinii using dog bait have been added.

CONCLUSION

The predominance of Lu. cruzi in the urban area; the great prevalence of Lu. forattinii in most of the outlying areas studied and the anthropophily of this latter species, as well as the strong affinity of these species with Lu. longipalpis, the main vector of visceral leishmaniais in other areas of the Americas, suggest the participation of both in the transmission of the disease in Corumbá.

Monthly variation in natural infection of the sandfly Lutzomyia ayacuchensis with Leishmania mexicana in an endemic focus in the Ecuadorian Andes

In order to collect information on the role of Lutzomyia ayacuchensis in the transmission of leishmaniasis in a newly discovered Andean endemic focus in Ecuador, a longitudinal field study was carried out over 13 months. Monthly dissections were made of a minimum of 200 anthropophilic sandflies, collected at night during the month. A total of 2600 flies was separated from a small number of Lu. osornoi, another anthropophilic species in the area, and dissected; 95 (3.65%) were naturally infected with Leishmania mexicana promastigotes. The parasites were always located in the sandfly midgut. The current study revealed a marked monthly variation both in natural infections with Leishmania and in biting activity of sandflies in the endemic area, demonstrating a high transmission rate during the period from the early rainy season to the early or mid dry season (February to July).

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

Between July 1983 and December 1984 natural flagellate infections were found in 114 (1%) of 11,586 female phlebotomine sandflies (Diptera: Psychodidae) of 21 species. A further 1084 females of 17 other species were not infected. Identification of the organisms on a number of occasions confirms the exclusive parasite/vector relationship of Leishmania mexicana amazonensis/Lutzomyia flaviscutellata and Le. braziliensis braziliensis/Psychodopygus "wellcomei". Undescribed or unidentified Leishmania spp. were isolated from Lu. shawi, Lu. ubiquitalis, Lu. whitmani, Ps. hirsutus, Ps. paraensis Ps. "wellcomei", and trypanosomes from Lu. nordestina and Lu. trinidadensis. Flagellate infections were recorded in 8 of 21 species examined for the first time, and some were isolated directly from insects into cultures. Le. b. braziliensis was transmitted to a hamster by the bite of a wild-caught, naturally infected Ps. "wellcomei". 7 of the 35 infected Ps. "wellcomei" were allowed to oviposit and the eggs were reared to adults. Four produced Ps. wellcomei males only, confirming the rôle of this species as the major vector of Le. b. braziliensis.

Leishmaniasis in Brazil: XX. Prevalence of "enzootic rodent leishmaniasis" (Leishmania mexicana amazonensis), and apparent absence of "pian bois" (Le. braziliensis guyanensis), in plantations of introduced tree species and in other non-climax forests in eastern Amazônia

In Amazonian Brazil most human leishmaniasis is due to Leishmania braziliensis s.l. and is acquired during the clearing of primary climax forest. One of the largest deforestation projects has taken place on the JARI property where plantations of exotic tree species are grown for paper pulp. The ability of the regional leishmaniasis enzootics to invade plantations was investigated. CDC light-trap catches indicated the phletobomine vectors of Le. b. guyanensis (causing "pian bois" in man) to be very scarce in JARI plantations compared to native-forest controls. It is concluded (drawing on other observations) that the vectors of "pian bois" are unlikely to thrive in any secondary forest. In contrast, catches from mammal traps and rodent-baited (Disney) traps demonstrated the presence in JARI plantations of infected Proechimys guyannensis and large populations of Lutzomyia flaviscutellata, respectively the major rodent reservoir and sandfly vector of Le. mexicana amazonensis. Alone amongst the local vectors of human cutaneous leishmaniasis, Lu. flaviscutellata is adapted to non-climax forests (primary or secondary, natural or man-made; synopsis given). It is predicted that the public health importance of Le. m. amazonensis is unlikely to diminish following the development of Amazônia. This is worrying because ca. 30% of Le. m. amazonensis infections in man cause highly-disfiguring, incurable "diffuse cutaneous leishmaniasis".

Leishmaniose tegumentar americana na Ilha Grande. Rio de Janeiro: V. Observações sobre a biologia dos transmissores em condiçoes naturais

Durante um surto de Leishmaniose Tegumentar Americana (LTA) na Praia Vermelha, Ilha Grande, município de Angra dos Reis, Rio de Janeiro, foram coletados 4.192 exemplares de flebotomíneos em ambiente domiciliar e silvestre, com isca animal e outros abrigos naturais, durante o período de janeiro de 1976 a abril de 1977. Entre o total de 11 espécies coletadas encontraram-se 2.493 exemplares de Lutzomyia intermedia, 1.594 de Lutzomyia migonei e 105 exemplares de outras espécies. A L. intermedia apresentou densidade mais elevada no domicílio humano, enquanto a L. migonei apresentou coletas mais rendosas com iscas animais e galinheiros. O sinantropismo e a elevada densidade no ambiente domiciliar incriminam as espécies L. intermedia e L. migonei como as prováveis vetoras da LTA na Ilha Grande.

Leishmania in phlebotomid sandflies. IV. The transmission of Leishmania mexicana amazonensis to hamsters by the bite of experimentally infected Lutzomyia longipalpis

Leishmania mexicana amazonensis was cyclically transmitted in the laboratory from hamster to hamster by single bites of experimentally infected Lutzomyia longipalpis . The sandflies were denied suitable conditions for oviposition and were induced to take a second, infecting, meal while still gravid. In three transmissions, cutaneous lesions developed rapidly on two hamsters, whereas that on the third remained small for 8 months, almost disappeared, and then grew to the usual large size. In some infected flies, parasites migrated to the pharynx and buccal cavity but then died and disintegrated; in others, healthy parasites were attached to the cuticular intima of the oesophagus and pharynx by hemidesmosomes. The common failure of leishmaniae to become established in the foregut of many experimentally infected sandflies may be because parasites die after migration and not because they fail to migrate. One cause of the death may be a lack of plant juices, a food of sandflies in nature. At the second potentially infecting feed, sandflies usually probed many times and took either no blood or only a small meal. It is suggested that parasites in the foregut block the pores of cibarial sensilla which probably control engorgement; such an interference would be an advantage in the evolution of Leishmania .