Distribution Of Sand Flies Research Articles

Distribution and Bionomic of Sand Flies in Five Ecologically Different Cutaneous Leishmaniasis Foci in Morocco

Cutaneous and visceral leishmaniases are endemic in Morocco. Their geographical distribution is well known. It has been related to bioclimatic factors. However, in 2008, two new cutaneous leishmaniasis foci appeared out of the known risk areas. Hence, we have undertaken this entomological survey in five foci situated in different bioclimatic areas to better understand the distribution and the epidemiology of this disease. Results of this study, undertaken during 2011, showed the predominance of Phlebotomus sergenti (55.8%) followed by Ph. perniciosus (12.9%), Ph. longicuspis (12.3%), and Ph. papatasi (12.0%). Ph. sergenti was active during 6 months in subhumid area and 8 months in arid, semiarid, and Saharan areas. Compared to previous studies, our results show a rise in Ph. sergenti abundance and an extension of its activity period. These results could explain the increase in anthroponotic cutaneous leishmaniasis incidence in Morocco and its extension to new nonendemic regions. Ph. perniciosus and Ph. longicuspis have also displayed a large distribution and a long activity period indicating a high potential risk of Leishmania infantum transmission in the studied areas.

SandflyMap: leveraging spatial data on sand fly vector distribution for disease risk assessments

We feature SandflyMap (www.sandflymap.org), a new map service within VectorMap (www.vectormap.org) that allows free public online access to global sand fly, tick and mosquito collection records and habitat suitability models. Given the short home range of sand flies, combining remote sensing and collection point data give a powerful insight into the environmental determinants of sand fly distribution. SandflyMap is aimed at medical entomologists, vector disease control workers, public health officials and health planners. Data are checked for geographical and taxonomic errors, and are comprised of vouchered specimen information, and both published and unpublished observation data. SandflyMap uses Microsoft Silverlight and ESRI's ArcGIS Server 10 software platform to present disease vector data and relevant remote sensing layers in an online geographical information system format. Users can view the locations of past vector collections and the results of models that predict the geographic extent of individual species. Collection records are searchable and downloadable, and Excel collection forms with drop down lists, and Excel charts to country, are available for data contributors to map and quality control their data. SandflyMap makes accessible, and adds value to, the results of past sand fly collecting efforts. We detail the workflow for entering occurrence data from the literature to SandflyMap, using an example for sand flies from South America. We discuss the utility of SandflyMap as a focal point to increase collaboration and to explore the nexus between geography and vector-borne disease transmission.

Sand flies (Diptera, Psychodidae, Phlebotominae) from Central Amazonia and four new records for the Amazonas state, Brazil

Sand flies from Central Amazonia and four new records for the Amazonas state, Brazil. A survey was conducted in May and June 2008 to study the fauna of insects in Central Amazonia, Brazil. As part of the survey, we report here that sixty species of phlebotomine were identified, totaling 13,712 specimens from 13 genera. The collection sites were located at the border between the states of Para and Amazonas, comprising three municipalities from the Amazonas state (Borba, Maues, and Nhamunda). Malaise, CDC and Shannon traps were used to collect the insects. Most of the sand flies were collected by CDC traps (89.5%), while Malaise and Shannon traps collected 7% and 3.5%, respectively. The most abundant genera, representing 97.1% of the total sand flies identified were: Trichopygomyia Barretto, 1962 (47.6%), Psathyromyia Barretto, 1962 (17.9%), Psychodopygus Mangabeira, 1941 (17.5%) and Trichophoromyia Barretto, 1962 (14.3%). The genera with the largest number of species identified were: Psychodopygus (14), Psathyromyia (10), Evandromyia Mangabeira, 1941 (7), Trichophoromyia (5) and Trichopygomyia (5). The most abundant species was Trichopygomyia trichopyga (Floch & Abonnenc, 1945), which represented 29% of the total sand flies identified. Here we also report new records for four species in the Amazonas state: Ps. complexus (Mangabeira, 1941), Ps. llanosmartinsi Fraiha & Ward, 1980, Ty. pinna (Feliciangeli, Ramirez-Perez & Ramirez, 1989), and Th. readyi (Ryan, 1986). The results of this study provide new, additional information on the distribution of sand flies in the Amazon and increase the number of species in the Amazonas state from 127 to 131.

The role of Palmyra palm trees (Borassus flabellifer) and sand fly distribution in northeastern India

Visceral leishmaniasis (VL), known as Kala-azar in India, is a parasite transmitted by the bite of the sand fly vector Phlebotomus argentipes. Published information on the species indicates it is a poor flyer, mainly hopping and gliding. This study describes the vector as more arboreal than previously documented. Data collected indicate the ability of P. argentipes and Sergentomyia spp to attain vertical heights in Palmyra palm trees Borassus flabellifer up to 18.4 m above ground level. To determine if sand flies were either climbing the tree trunk to rest in the canopy or flying, sticky traps were set around the tree trunk and checked for captures overnight. CDC traps set in the palm tree canopy resulted in the capture of 5,067 sand flies, 3,990 of which were P. argentipes. Traps were set during daylight hours to determine if sand flies remained and rested in the canopy. A total of 128 sand flies were trapped over 29 trap days in the palm trees. With the CDC traps, 130 P. argentipes and no Sergentomyia spp were captured. The converse was true for the sticky traps set around tree trunks 3 m below the CDC traps. Of the 105 sand flies collected, only one was P. argentipes and 104 were Sergentomyia spp. As reported elsewhere, this indicates Sergentomyia spp tend to climb and hop, wheareas P. argentipes are capable of longer and more sustained flight. Data presented herein suggest that P. argentipes is more exophylic and exophagic than previously reported. These findings have implications for sand fly control.

Environmental factors underlying spatial patterns of sand flies (Diptera: Psychodidae) associated with leishmaniasis in southern Sinai, Egypt

Although Leishmania major is endemic in parts of the Sinai of Egypt, the ecology and distribution of Leishmania sand fly vectors in southern Sinai has not been well characterized. Accordingly, additional sand fly samples were obtained at 41 sites in the southern Sinai region during 1996–1997, and analyzed to improve the characterization of risk of sand fly-borne pathogens. Using a Geographic Information System (GIS), species-specific spatial distributions that might suggest zoonotic cutaneous leishmaniasis (ZCL) risk areas were determined in relation to contextual environmental factors, including geology, hydrogeology, climate variables and elevation. Southern Sinai was characterized by a diverse sand fly fauna (eight Phlebotomus species), probably attributable to highly variable landscape and environmental factors. Phlebotomus alexandri, Phlebotomus kazeruni and Phlebotomus sergenti were widespread and abundant, Phlebotomus papatasi and Phlebotomus bergeroti were less frequent, and Phlebotomus arabicus, Phlebotomus major and Phlebotomus orientalis had highly restricted distributions. Logistic regression models indicated that elevation and climatic conditions were limiting determinants for the distributions of sand flies in southern Sinai. Based on the predicted distribution of P. papatasi, a recognized vector of L. major, about one-quarter of southern Sinai may be at high risk of ZCL. Risk areas for the suspected ZCL vector P. bergeroti had a more patchy distribution. Results suggest that future studies should include other factors related to vector abundance, vector competence, human population, and parasite and reservoir host(s) to produce more comprehensive ZCL transmission risk maps, thus helping in planning effective prevention and control strategies.

Distribution, fauna and seasonal variation of sandflies, simultaneous detection of nuclear internal transcribed spacer ribosomal DNA gene of Leishmania major in Rhombomys opimus and Phlebotomus papatasi, in Natanz district in central part of Iran.

Zoonotic cutaneous leishmaniasis (ZCL) due to Leishmania major is increasing in many parts of Iran. This disease originally is a disease found in gerbils. Leishmania parasites are transmitted by sandflies that live and breed in gerbil burrows. Nested PCR amplified Leishmania ITS1-5.8S rRNA gene in both main reservoir host "Rhombomys opimus" and in the "Phlebotomus papatasi" main vector of ZCL, in Iran. Population differentiation and seasonal variation of sandflies were analyzed at a microgeographical level in order to identify any isolation by distance, habitat or seasons. Populations of sandflies were sampled from the edges of villages in Natanz, Isfahan province, Iran, using the Centers for Disease Control traps and sticky papers. Individual sandflies were identified based on external and internal morphological characters. Nested PCR protocols were used to amplify Leishmania ITS1-5.8S rRNA gene, which were shown to be species-specific via DNA sequence. A total of 4500 sandflies were collected and identified. P. papatasi, Phlebotomus sergenti and Phlebotomus jacusieli from genus Phlebotomus and Sergentomyia sintoni and Sergentomyia clydei from genus Sergentomyia were identified in this region. P. papatasi was the most abundant sandfly in the collections. Ten out of 549 female P. papatasi and four out of 19 R. opimus were found to be infected with L. major. Seasonal activity of sandflies starts in June and ends in November. Abundance of P. papatasi was in September. Finding and molecular typing of L. major in P. papatasi and R. opimus confirmed the main vector and reservoir in this region.

Combining climatic projections and dispersal ability: a method for estimating the responses of sandfly vector species to climate change.

BackgroundIn the Old World, sandfly species of the genus Phlebotomus are known vectors of Leishmania, Bartonella and several viruses. Recent sandfly catches and autochthonous cases of leishmaniasis hint on spreading tendencies of the vectors towards Central Europe. However, studies addressing potential future distribution of sandflies in the light of a changing European climate are missing.MethodologyHere, we modelled bioclimatic envelopes using MaxEnt for five species with proven or assumed vector competence for Leishmania infantum, which are either predominantly located in (south-) western (Phlebotomus ariasi, P. mascittii and P. perniciosus) or south-eastern Europe (P. neglectus and P. perfiliewi). The determined bioclimatic envelopes were transferred to two climate change scenarios (A1B and B1) for Central Europe (Austria, Germany and Switzerland) using data of the regional climate model COSMO-CLM. We detected the most likely way of natural dispersal (“least-cost path”) for each species and hence determined the accessibility of potential future climatically suitable habitats by integrating landscape features, projected changes in climatic suitability and wind speed.Results and Relevance Results indicate that the Central European climate will become increasingly suitable especially for those vector species with a current south-western focus of distribution. In general, the highest suitability of Central Europe is projected for all species in the second half of the 21st century, except for P. perfiliewi. Nevertheless, we show that sandflies will hardly be able to occupy their climatically suitable habitats entirely, due to their limited natural dispersal ability. A northward spread of species with south-eastern focus of distribution may be constrained but not completely avoided by the Alps. Our results can be used to install specific monitoring systems to the projected risk zones of potential sandfly establishment. This is urgently needed for adaptation and coping strategies against the emerging spread of sandfly-borne diseases.

Distribution of Sandflies (Diptera, Psychodidae) in Two Ionian Islands and Northern Greece

A field study on the distribution of phlebotomine sandflies was carried out during summer months of 2009 and 2010 in eight sites in two Ionian islands and in northern Greece. A total of 490 sandflies (74.5% females) were collected. Six species of the Phlebotomus genus and two of the Sergentomyia genus were identified. The species with the widest distribution in the islands were Phlebotomus neglectus (32.8%), Phlebotomus similis (30.3%), Phlebotomus tobbi (16.7%), and P. perfiliewi (15.9%), whereas P. simici (50%), P. neglectus (24.5%), and P. tobbi (9.6%) predominated in the mainland. As most of these species are proven or suspected vectors of human and animal pathogens, prevention measures have to be taken in these areas during the summer months when sandflies are active.

Distribución de flebotominos (Diptera: Psychodidae) en Quintana Roo, México

Se llevó a cabo un estudio faunístico en el estado de Quintana Roo para conocer la distribución, riqueza y abundancia de los flebotominos. Se observó una gran variabilidad del promedio deespecies y abundancia dentro y entre tres diferentes zonas (sur, centro y norte) en el estado. La mayor abundancia y riqueza se registró en la zona norte, en la zona centro y sur se capturaron igual número de especies, y la zona centro tuvo la menor abundancia. En cada zona fueron diferentes las especies dominantes, aunque, Lutzomyia shannoni y Lutzomyia cruciata se registraron dentro de las más dominantes distribuidas en las tres zonas. Entre las especies dominantes que se presentan en el estado se encuentran aquellas que son incriminadas como vectores de leishmaniasis en la Península de Yucatán. Los factores ambientales que se presentan en el estado son reflejados en las abundancias encontradas en las diferenteszonas de Quintana Roo.

Spatial distribution of phlebotomine sand flies in the Aydin Mountains and surroundings: the main focus of cutaneous leishmaniasis in western Turkey

An entomological survey was conducted to determine the spatial distribution of phlebotomine fauna and understand the effect of environmental factors. The entomological survey was carried out during 2006-2007 in a study area in the rural area of Aydin province, near the Kusadasi town where VL, CL, and canine leishmaniasis (CanL) are endemic. In 2006 and 2007, 132 locations were sampled using sticky traps mainly on embankments. Detailed environmental and meteorological information was also collected for each location. The results of entomological studies indicated that the probable vectors are Phlebotomus tobbi and P. neglectus for VL and CanL, and P. similis for CL in this western leishmaniasis focus. The data revealed a correlation between their presence and spatial variables such as altitude, sampling site location, and humidity. The distribution areas of probable vector species in this study area allowed the identification of risk levels, which may provide useful information to guide the leishmaniasis research in endemic regions.

Seasonal and spatial changes of sand fly species in a canyon in the Carmel Mountains

Altogether, 4,008 sand flies belonging to seven species were collected over a period of one year in the micro-habitats of a single canyon in the Carmel Mountain ridge. The three most abundant were P. arabicus, P. tobbi, and P. simici. Our results suggest that none of the seven sand fly species was indifferent to the heterogeneity of the microenvironment inside the canyon. Apart from the rare P. perfiliewi, which was only collected on the upper part of the south-facing slope, and P. tobbi, which clustered on the north-facing slope, the bulk of the other sand flies were caught on the bottom of the canyon. During the summer, the catches of all sand fly species increased to reach their maximum number in August and September. In April and May, there was lush vegetation and humidity, so species were distributed evenly throughout their habitats. With the onset of summer dryness, the sand flies concentrated in the humid habitats. The rate of concentration was essentially higher for males than for females, and this variation may result from differences in the behavior of the two sexes. During our study, none of the 2,318 dissected female sand flies were positive for Leishmania promastigotes.

Evaluation of a metofluthrin fan vaporizer device against phlebotomine sand flies (Diptera: Psychodidae) in a cutaneous leishmaniasis focus in the Judean Desert, Israel

The OFF! Clip-On fan vaporizer device releasing metofluthrin was evaluated against phletobomine sand flies in the Judean Desert, Israel, in October, 2009. A total of 76,400 sand flies was collected, with male flies representing 98.3%Phlebotomus sergenti and 1.7%P. papatasi. Females comprised 43.0% of the total catch and included 6.7% blood-fed females. Similar proportions of flies were collected in both suction and sticky traps. In trials with unbaited suction traps, similar numbers of sand flies were collected in traps with a metofluthrin device, blank device, or no device (i.e., suction only). In suction traps baited with CO(2) , higher numbers of P. sergenti males and blood-fed females were collected in traps with a blank device compared to traps with a metofluthrin device. In sticky traps baited with CO(2) , there were no significant differences between catches in traps with a metofluthrin device, blank device, or no device. The results suggest metofluthrin from the device is not repellent against sand flies in a field environment despite showing insecticidal activity against flies collected in suction traps.

Characteristics of resting and breeding habitats of adult sand flies in the Judean Desert

Recently, in several areas of the Middle East, a sharp increase of cutaneous leishmaniasis was observed in suburbs of larger towns including Jerusalem. In some of these areas, poor housing conditions and unsuitable waste management was suspected to provide ideal conditions for sand fly breeding, but hard data on diurnal resting sites and breeding habitats of most sand fly species are scant. In this study, we chose 16 sites on both slopes and the bottom of a natural valley in the Judean Desert to conduct a survey of sand fly distribution with emergence traps. Altogether, 1,261 sand flies, 52%Phlebotomus syriacus, 22%P. sergenti, 14%P. papatasi and 12%P. tobbi were caught. About two thirds of the flies caught were resting, while the other third emerged from breeding sites. All four species showed clear preferences for resting and breeding sites, but generally, most sand flies were breeding in the more humid habitats, namely the bottom of the valley, the adjacent north facing slope, terraces on the north facing slope, and caves. The vegetation cover also appeared to be important for resting habitats; on the bottom of the valley more than six times as many sand flies were collected in areas covered by dense vegetation than in areas with low vegetation cover. P. sergenti seemed also to better tolerate the drier habitats, which might explain the abundance of this species in the arid Judean Desert.

Sequel to Kitzmiller's Anopheline Names: Their Derivations and Histories

The derivations of the names of 74 Anopheles species and one subgenus are explained together with accounts of the life and scientific work of people who have been honored by having a mosquito named after them. Descriptive accounts are given of geographical locations, whether towns, regions or counties, that have had anopheline species named after them.

Distribution of Phlebotomine Sand Flies (Diptera: Psychodidae) in a Primary Forest-Crop Interface, Salta, Argentina

Disordered urbanization and deforestation are the main activities proposed as causal factors of re-emergence of American cutaneous leishmaniasis caused by Leishmania braziliensis. The purpose of this work was to investigate, in the hyperendemic area of Argentina, the distribution of Phlebotomine sand flies at the modified primary vegetation-crop interface, as one of the potential sites where the effects of changing landscape on sand fly populations may be manifested. Twenty samplings were made between June 2004 and August 2005. The traps to catch sand flies were set on two consecutive nights every month (except in 5 mo, where it became every 15 d). The relationship between sand fly abundance and meteorological and landscape variables was analyzed using non-metric multidimensional scaling and Kendall's correlation coefficients. Lutzomyia neivai (Pinto) was the most abundant species, followed by Lutzomyia migonei (França), Lutzomyia cortelezzii (Brèthes), Lutzomyia shannoni (Dyar), and Lutzomyia punctigeniculata (Floch and Abonnenc). Traps located close to modified areas collected the greatest numbers of sand flies, whereas traps located in the least modified area (adjacent to the primary vegetation) collected the fewest. There was a strong negative correlation between the abundance of sand flies and precipitation. This study shows that even small modifications in the landscape led to an increase in sand fly abundance, mainly Lu. neivai, a Leishmania braziliensis vector. This underscores the need for recommendations about the risk of American cutaneous leishmaniasis before any environmental intervention is done in an endemic area, as well as for the monitoring of sand fly population dynamics at the site of intervention, before, during, and after the process.

Sand flies of Nicaragua: a checklist and reports of new collections

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.

Visceral leishmaniasis in border areas: clustered distribution of phlebotomine sand flies in Clorinda, Argentina

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.

Epidemiology of paediatric visceral leishmaniasis in Hebron district, Palestine

Seventy-six cases of visceral leishmaniasis (VL) were reported from the Hebron district of the West Bank, Palestine between 1993 and 2007. All cases were in children less than 9 years old (median age 2 years). The average number of cases was 5.06/year and the average annual incidence was 3.02/100000 children. Ribosomal internal transcribed spacer 1 (ITS1) PCR-RFLP was performed using DNA extracted from two cultures and 36 archived Giemsa-stained slides from VL patients. Leishmania infantum was revealed as the causative agent of VL in the focus. Isoenzyme analysis identified two isolates as zymodeme MON-1. A serological survey of 455 children screened for serum anti-Leishmania antibodies revealed 8.4% seropositivity. Seropositivity was highest for children in households of previous VL cases [odds ratio (OR) 7.5; 95% CI 3.17-17.61; P<0.001] and among people who had domestic dogs and/or other animals (OR 2.4; 95% CI 1.19-4.68; P=0.017). No difference was seen between males and females (P=0.073). A preliminary survey of sand fly distribution showed the abundance of two putative vector species: Phlebotomus syriacus (45%) and Ph. tobbi (10%). The focus of VL in Hebron district was shown to follow the epidemiological pattern of paediatric disease characteristic of the Mediterranean region.

Distribution of sand flies in El-Nekheil province, in Al-Madinah Al-Munawwarah region, western of Saudi Arabia

An entomological survey for sand flies was conducted at an area of cutaneous leishmaniasis--El-Nekheil in Northeast Al-Madinah Al-Munawwarah, Saudi Arabia. Standardized sampling with Centers for Disease Control (CDC) light traps and sticky traps was employed to determine monthly trends in species composition, density, sex ratio, and reproductive status and Leishmania infection rate of vector sand flies. A total of 621 sand flies were collected from March 2006 to November 2007. Six species representing two genera were identified, three Phlebotomus species: P. papatasi, P. sergenti, and P. bergeroti; and three Sergentomyia species: S. antennata, S. sergenti, and S. shewtzi. Phlebotomus papatasi was the predominant anthropophagic species found and comprised more than 70% of the sand fly population. A population peak (June) was observed for this species. The density of P. papatasi intra-domiciliary was higher than extra-domiciliary stations and inflated by a greater proportion of female flies. Of 189 dissected Phlebotomus females, 43% were blood-fed. No Leishmania parasites were found. The proportion of gravid P. papatasi increased progressively during the 5-month period from May to September and averaged 38%. Proportions of gravid flies may be a valid indicator of the physiological age and epidemiologic importance of the vector sand fly population at this focus.

Epidemiological monitoring of American tegumentary leishmaniasis: molecular characterization of a peridomestic transmission cycle in the Amazonian lowlands of Bolivia

Human-made and environmental changes constitute a major risk factor for the (re-)emergence and spread of leishmaniasis; surveillance of the transmission cycle is essential in this context. This study integrated entomological and molecular parasitological techniques to document the transmission pattern of a peridomestic focus of Leishmania in the Isiboro Secure area of Bolivia. First the spatial distribution and relative density of phlebotomine sand flies, genus Lutzomyia, were established. Lutzomyia shawi was the predominant species in domestic and peridomestic environments (90% from all collections). Second, direct application of the hsp70 PCR to sand fly extracts detected Leishmania infections in Lu. shawi only, and gave an estimated infection rate of 0.21 to 0.38%. The cleavage of the hsp70 amplicon with restriction enzymes (hsp70 PCR-RFLP) allowed identification of Le. (V.) braziliensis and Le. (V.) guyanensis in Lu. shawi captured in the same village. These two parasite species were also found in humans from the study region, supporting the co-existence of two transmission cycles involving the same sand fly species. This study demonstrated the use of PCR-RFLP in the identification of Leishmania in sand fly pools which could lead to the development of methods for screening large sand fly populations in Latin America.