Transmission Of Cutaneous Leishmaniasis Research Articles

Comparison of the diversity of phlebotomine sand flies (Diptera: Psychodidae) in two physiographic regions with different bioclimatic conditions and cutaneous leishmaniasis transmission

Comparison of the diversity of phlebotomine sand flies (Diptera: Psychodidae) in two physiographic regions with different bioclimatic conditions and cutaneous leishmaniasis transmission

Indicators sand flies and environment associated to spatial landscaping change in Choco Biosphere Reserve UNESCO.

Sand flies are insects vector associated with terrestrial forest ecosystems; in the Ecuadorian Andes, they participate in the transmission of human cutaneous leishmaniasis. This geographical area is an opportunity to evaluate the role of sand flies as bioindicators od the degree of intervention of a tropical humid forest ecosystems (THF) associated with changes in the ecology of the local landscape. CDC-light traps were used for collecting adults' sand flies in February 2020 in a humid tropical forest within Choco Biosphere Reserve. All species were identified using morphological keys. Analysis data about abundance, richness, species accumulation, diversity index, species composition communities, species sex proportion, spatial sand flies environmental, Renyi's Diversity Profile were performed to compare six spatial habitats in Mashpi locality, Ecuador. Sand flies were collected (n-1435); the main species are represented by Th. reburra Ny. trapidoi, Pa. aclydifera, Py. panamensis and Lu. hartmanni. Only Th. reburra is associated with not intervened forest, while the other 3 species are associated with intervened forest within Mashpi in the Choco Biosphere Reserve. The secondary forest has the major sandflies' richness, while the primary forest exhibits the major abundance. The results indicated that Th. reburra is a sandfly restricted to the Andean Forest and is a bioindicator of the high environmental health quality of the forest, while Ny. trapidoi and Pa. aclydifera are bioindicators of environmental disturbances in the forest. Additionally, Ps. panamensis, Lu. hartmanni and Ny. trapidoi are bioindicators of human impact and the risk of leishmaniasis.

Characterisation of an area of coexistent visceral and cutaneous leishmaniasis transmission in the State of Piauí, Brazil.

In Brazil, transmission of visceral and cutaneous leishmaniasis has expanded geographically over the last decades, with both clinical forms occurring simultaneously in the same area. This study characterised the clinical, spatial, and temporal distribution, and performed entomological surveillance and natural infection analysis of a leishmaniasis-endemic area. In order to characterise the risk of leishmaniasis transmission in Altos, Piauí, we described the clinical and socio-demographic variables and the spatial and temporal distribution of cases of American visceral leishmaniasis (AVL) and American cutaneous leishmaniasis (ACL) cases and identified potential phlebotomine vectors. The urban area concentrated almost 54% of ACL and 86.8% of AVL cases. The temporal and spatial distribution of AVL and ACL cases in Altos show a reduction in the number of risk areas, but the presence of permanent disease transmission foci is observed especially in the urban area. 3,808 phlebotomine specimens were captured, with Lutzomyia longipalpis as the most frequent species (98.45%). Of the 35 females assessed for natural infection, one specimen of Lu. longipalpis tested positive for the presence of Leishmania infantum and Leishmania braziliensis DNA. Our results indicate the presence of risk areas for ACL and AVL in the municipality of Altos and highlight the importance of entomological surveillance to further understand a possible role of Lu. longipalpis in ACL transmission.

Molecular identification of Leishmania tropica in mammals occurring in human-inhabited areas of a cutaneous leishmaniasis endemic focus in North-West Pakistan.

Cutaneous Leishmaniasis is endemic in the tribal district of Khyber near the Pak-Afghan border and is caused by Leishmania tropica. In Pakistan, cutaneous leishmaniasis caused by L. tropica is considered anthroponotic and is thought to be maintained by a human-sand fly-human transmission cycle. Along with humans, other mammals may also be acting as reservoir hosts of leishmaniasis in the study area. To investigate the role of non-human mammals in the transmission of leishmaniasis, blood samples were collected from 245 animals from the CL endemic district of Khyber, Pakistan. Leishmania parasite in these samples was detected by amplifying the species-specific sequences in minicircle kinetoplast DNA, using PCR. L. tropica DNA was detected in 18 (7.35%) samples, comprising 11 cows (Bos taurus), 6 goats (Capra hircus), and 1 dog (Canus lupus familiaris). Only a single cow and dog had a leishmaniasis-like lesion, and the remaining positive samples were asymptomatic. None of the tested sheep (Ovis aries) and rat (Rattus rattus, Rattus norvegicus) was positive. The present study reports the first instance of molecular detection of L. tropica in domestic animals. Our study indicates that along with humans' cows, goats and dogs may also be playing an important role in the transmission of anthroponotic cutaneous leishmaniasis in district Khyber in particular and Pakistan in general.

The effect of El Niño and La Niña episodes on the existing niche and potential distribution of vector and host species of American Cutaneous Leishmaniasis

Leishmaniasis is a zoonotic disease transmitted to humans by a protozoan parasite through sandfly vectors and multiple vertebrate hosts. The Pan American Health Organization reported a declining trend in cases, with Brazil, Colombia, Peru, Nicaragua, and Bolivia having the most cases in 2020. There are still knowledge gaps in transmission and the parasite-host relationship. Ecological niche modeling has been used to study host-vector relationships, disease dynamics, and the impact of climate change. Understanding these aspects can aid in early surveillance and vector control strategies. The potential distribution of five host species associated with the transmission of cutaneous leishmaniasis (CL) was modeled. Occurrence data were collected for each host species, and environmental variables were used to build the models. Climatic data from El Niño, La Niña, and Neutral episodes were used to compare the predicted distributions. Additionally, the potential distributions of four vector species were compared to identify overlaps with host species. Niche analysis was conducted to evaluate changes in vector niches across episodes and to identify host-vector pairs based on niche overlap in geographic and environmental spaces. After spatial thinning, 467 records were obtained, and 1,190 candidate models were evaluated for each species. Results showed the distribution of occurrences in the environmental space, highlighting a high risk of extrapolation beyond the calibration areas. Movement-Oriented Parity analysis revealed distinct distribution patterns under different climate conditions, with areas of environmental similarity identified. Bradypus variegatus exhibited a broad potential distribution, while Dasypus novemcinctus and Didelphis marsupialis had more restricted ranges. Sylvilagus braziliensis covered most of the Neotropics. Our study provides valuable insights into ecological niches and geographic ranges of these species, contributing to the understanding of cutaneous leishmaniasis transmission dynamics.

Investigating potential sand fly vectors after the first reported outbreak of cutaneous leishmaniasis in Ghana

BackgroundLeishmaniasis is a parasitic disease caused by species of the genus Leishmania, which are transmitted through the bite of infected female sand flies. Since the first reported outbreak of cutaneous leishmaniasis in Ghana, in 1999, there has been limited published information on its vectors and reservoir hosts there. Previous studies have shown strong dominance of the sand fly genus Sergentomyia over the genus Phlebotomus in Ghana. Thus the aim of this study was to determine the possible sand fly vector species in Ghana, as well as their human-feeding behavior, from the time of the first reported outbreak of CL in the country.MethodsSand flies were collected from randomly selected houses in three communities. They were identified and used for blood meal source identification and the detection of Leishmania infection using molecular methods. ResultsA total of 1051 female sand flies were morphologically identified, of which Sergentomyia africana africana (29%) was the predominant species. Among the 275 female sand flies that had blood-fed, the identified blood meal sources included chicken (33.8%) and goat (12.4%); the percentage of human blood meals was 32%. Single-source and mixed-source blood meals were identified in Sergentomyia africana africana (11.6%), Sergentomyia ingrami (14.9%) and Sergentomyia simillima (20%), with S. simillima having the highest proportion of blood meals that included human blood (14.6%). Using molecular methods, unfed sand flies and identified human-feeding species were examined for the presence of Leishmania DNA. Pool screening analysis revealed three pools of S. ingrami positive for Leishmania major DNA, with an infection rate of 1.27% (95% confidence interval 2.467–3.647).ConclusionsThe findings suggest that some Sergentomyia species may be involved in the transmission of cutaneous leishmaniasis in Ghana. However, the role of S. ingrami as a vector of leishmaniasis in Ghana needs to be conclusively validated by isolating the parasite from this species and through experimental transmission studies.Graphical abstract

Diversity and geographical distribution of Leishmania species and the emergence of Leishmania (Leishmania) infantum and L. (Viannia) panamensis in Central-Western Venezuela

Transmission of cutaneous leishmaniasis in Venezuela reveals diverse and changing epidemiological landscapes, as well as a spectrum of clinical phenotypes presumed to be linked to a variety of Leishmania species. Central-western Venezuela constitutes one of the highest endemic epicenters in the country, and updated molecular epidemiological information is still lacking. Therefore, in this study we aimed to characterize the landscape of circulating Leishmania species across central-western Venezuela through the last two decades, performed comparisons of haplotype and nucleotide diversity, and built a geospatial map of parasite species distribution. A total of 120 clinical samples were collected from patients across the cutaneous disease spectrum, retrieving parasitic DNA, and further characterizing by PCR and sequencing of the HSP70 gene fragment. This data was later collated with further genetic, geospatial and epidemiological analyses. A peculiar pattern of species occurrence including Leishmania (Leishmania) amazonensis (77.63% N=59), Leishmania (Leishmania) infantum (14.47% N=11), Leishmania (Viannia) panamensis (5.26% N=4) and Leishmania (Viannia) braziliensis (2.63% N=2) was revealed, also highlighting a very low genetic diversity amongst all analyzed sequences. Geographical distribution showed that most cases are widely distributed across the greater urban-sub urban area of the Irribaren municipality. L.(L.) amazonensis appears to be widely dispersed throughout Lara state. Statistical analyses failed to reveal significance for any comparisons, leading to conclude a lack of association between the infective Leishmania species and clinical phenotypes. To the best of our knowledge, this is an unprecedented study which addresses comprehensively the geographical distribution of Leishmania species in central-western Venezuela throughout the last two decades, and the first to incriminate L. (L.) infantum as an etiologic agent of cutaneous leishmaniasis in this region. Our findings support that Leishmania endemism in central-western Venezuela is caused mainly by L.(L.) amazonensis. Future studies are needed to unveil additional details on the ecological intricacies and transmission aspects of leishmaniasis (i.e. sampling phlebotomines and mammals) and to adopt adequate public health prevention and control strategies and mitigate disease impact in this endemic region.

Peri-domestic risk factors associated with transmission of cutaneous leishmaniasis in selected areas in Hambantota District, Sri Lanka

The Ceylon Journal of Science is a peer-reviewed journal published quarterly by the University of Peradeniya, Sri Lanka in March, June, September and December. It is aimed at publishing high quality research articles on topics related to different disciplines in Science. The journal accepts original research articles, book reviews, reviews and mini-reviews, short communications, opinions, research notes, and commentaries and notes. The Journal has its own website https://site.pdn.ac.lk/cjs/. The journal strictly adheres to publication ethics as emphasized by the Committee on Publication Ethics (COPE). It is indexed in Sri Lanka Journals Online (SLJOL), Directory of Open Access Journals (DOAJ), Google Scholar and Zoological Records. According to the Google Scholar;H5-Index: 12H5-Median: 15According to the Exaly (1970 – 2021);Impact Factor: 0.6 (top 19%)Extended IF: 0.6 (top 19%)H-Index: 8 (top 28%)Citations/paper: 1.42

Discovery of the vector of visceral leishmaniasis, Phlebotomus (Artemievus) alexandri Sinton, 1928, in Kenya suggests complex transmission dynamics

Visceral and cutaneous leishmaniasis are endemic to specific regions due to the ecological preferences of phlebotomine sand flies and Leishmania spp. transmission. Sand fly entomological data in northern Kenya are scarce due to limited studies and neglect of leishmaniasis. The aim of this study was to investigate: (i) sand fly diversity and distribution; (ii) occurrence of Leishmania DNA within sand flies; and (iii) blood-meal sources of sand flies in Laisamis, northern Kenya. We conducted an entomological survey during February and March of 2021 in five areas of Laisamis sub-county using standard CDC light traps. A total of 1009 sand flies (394 male and 615 female) were morphologically identified, and representative samples verified by PCR amplification and sequencing of the cytochrome c oxidase subunit 1 (cox1) gene. Similarly, we identified blood-meal sources and Leishmania DNA in female sand flies by PCR amplicon sequencing of the vertebrate cytochrome b (cyt b) gene and internal transcribed spacer 1 (ITS1) of the 28S rRNA gene, respectively. Sergentomyia clydei (59.8%) was the most abundant sand fly species. Though collected mainly from one locality (Tirgamo), 14.8% of samples belonged to Phlebotomus (Artemievus) alexandri Sinton, 1928. We detected DNA of Leishmania major in 5.19% of Ph. alexandri, whereas Leishmania adleri DNA was detected in S. clydei (7.51%), Sergentomyia squamipleuris (8.00%), and Sergentomyia africanus (8.33%). Nine of 13 blood-fed sand flies had obtained blood from humans, of which 33.3% had L. major DNA. Both Ph. alexandri and S. clydei primarily fed on humans and could potentially be involved in the transmission of cutaneous leishmaniasis. The findings of this study contribute to the understanding of sand fly vector populations and their potential to transmit leishmaniasis in the area.

Seasonal Dynamics of Sand Flies (Diptera, Pshycodidae), Vectors of Cutaneous Leishmaniasis, in the City of Fez, Northern Morocco.

The infections transmitted by sand flies (Diptera, Psychodidae) pose always a real health problem due to the increasing number of cases detected each year and the annual emergence of new leishmaniasis outbreaks. This study evaluated the temporal evolution of six species of sand flies in five stations inventoried between May 2017 and April 2018, in order to determine for the first time the extent of cutaneous leishmaniasis (CL) transmission in the city of Fez. The monthly impact of Fez sand fly density has been studied using all multivariate statistical analyses, including multiple factor correspondence analysis (MCA), which were performed using XLSTAT and the version of SPSS 20.0 test. Differences between concentrations were considered significant if P < 0.05. To better study the results obtained, different ecological indices have been studied. This study showed that these vectors developed in different sectors of the city of Fez. A total of 816 sand flies were collected from five stations in the city, belonging to three species of the genus Phlebotomus (46.82%) and three species of the genus Sergentomyia (53.18%). The seasonal fluctuation of the average density followed a bimodal evolution for the three stations Dhar Richa, Ain Nokbi, and Boujloud. The stations of Ain Nokbi (0.87 ph/m2) and Dhar Richa (0.467 ph/m2) exposed the sites to a high average density with a maximum peak during August (1.965 ph/m2) and July (1.87 Ph/m2), respectively. S. minuta (44.24%), Ph. sergenti (26.96%), Ph. perniciosus (10.78%), and Ph. papatasi (9.07%) were the most qualified species. The calculated P value is above the 5% significance level, so the relative abundance of these species between study sites shows no significant difference. The period of phlebotomy activity of the genus Phlebotomus in Fez lasts seven months from May to November with a bimodal or trimodal evolution and varies according to the species or the surveyed station. The seasonal fluctuation of sand flies could be conditioned by climatic factors where the period of activity of the species coincides with the hot months (May, June, July, and August). We have observed that the temperature factor favors the prevalence of sand flies, while the difference in the relative abundance of species between the sites is related to the difference in the bioecological conditions of each site.

A conceptual model for understanding the zoonotic cutaneous leishmaniasis transmission risk in the Moroccan pre-Saharan area

Leishmanioses are of public health concern in Morocco, mainly the Zoonotic Cutaneous Leishmaniasis (ZCL) endemic in the Moroccan pre-Saharian area. Transmission of this disease depends on eco-epidemiological and socio-economic conditions. Therefore, a multivariable approach is required to delineate the risk and intensity of transmission. This will help outline main disease risk factors and understand interactions between all underlying factors acting on disease transmission at a local and regional scale. In this context, we propose a new conceptual model, the Biophysical-Drivers-Response-Zoonotic Cutaneous Leishmaniasis (BDRZCL), adapted to the Pre-Saharian area. The proposed model highlights how the physical and human drivers affect the environment and human health. The incidence of ZCL is linked to human activity and biophysical changes or by their interactions. The human response added to risk drivers are the main components that influence the biophysical part. This model improves our understanding of the cause-effect interactions and helps decision-makers and stakeholders react appropriately.

Update of the Phlebotominae Fauna with New Records for Argentina and Observations on Leishmaniasis Transmission Scenarios at a Regional Scale

Phlebotominae are small insects distributed in the Americas from Canada to Argentina and Uruguay, counting with more than 500 neotropical species. Some of them have a vectorial role in the transmission of Leishmania Ross, the causative agent of leishmaniases, a group of worldwide distributed diseases with different clinical manifestations and transmission cycles. Our aim was to update the Phlebotominae fauna of Argentina and to make observations on the American Cutaneous (ACL) and Visceral Leishmaniasis (AVL) transmission scenarios, according to the distribution of proven or suspected Leishmania vector species and recent changes in land use. Primary data (entomological captures) and secondary data (review of 65 scientific publications with Phlebotominae records) were used. With 9 new records, 46 Phlebotominae species are now recorded through the area comprising 14 political jurisdictions and 6 phytogeographic provinces. Distribution maps were constructed for the 5 proven or incriminated Leishmania vector species, and the evidence supporting the vectorial incrimination of these species is discussed. Three main ACL transmission scenarios are described in the phytogeographic provinces of the Yungas, Chaco, and Paranaense, associated with deforestation processes, while the transmission scenarios of AVL are urban outbreaks and scattered cases in rural areas. We update the available knowledge on the Phlebotominae fauna present in Argentina, emphasizing its epidemiological relevance in the current context of the increasing frequency of ACL outbreaks and geographic spread of AVL.

Updating Ecological and Behavioral Aspects of the Sandfly Fauna in the Vale do Ribeira Region, São Paulo State, Brazil.

Simple SummaryAnalyzing the biological and ecological characteristics of arthropods constitutes the basis for the entomological surveillance of vector-borne diseases. This is accomplished in order to implement vector surveillance and control programs. Thus, with the objective to update the distribution of sandflies in the main transmission region of cutaneous leishmaniasis in the state of São Paulo, we carried out a study of fauna in a modified environment, considering its environmental characteristics and climatic variables. Ecological indices such as richness, abundance, diversity, and equitability of the sandfly fauna in the region are presented.Some ecological parameters and the distribution of vectors in the municipality of Eldorado, Vale do Ribeira Region, São Paulo, were studied. Entomological surveys were carried out from September 2019 to March 2021. It was observed that a few ecological parameters, including richness, abundance, diversity, and equitability, were typical of a modified environment, where artificial ecotopes maintain the presence of sandflies throughout the year. A total of 11,668 sandflies were captured. The presence of five taxa were observed in Eldorado, with low diversity and high dominance of Nyssomyia intermedia next to Ny. neivai, which are sympatric species. The results presented reinforce the importance of these species in anthropized areas in the transmission of cutaneous leishmaniasis (CL) agents and the need for entomological monitoring. Psathyromyia pascalei was encountered for the first time in the municipality, expanding the known area of distribution of this species in a modified environment.

Risk Assessment of the Role of the Ecotones in the Transmission of Zoonotic Cutaneous Leishmaniasis in Central Tunisia.

Zoonotic cutaneous leishmaniasis (ZCL), endemic in Central and Southern Tunisia, is caused by Leishmania major (Kinetoplastida: Trypanosomatidae), which is transmitted by the sand fly Phlebotomus papatasi. In Tunisia, the fat sand rat Psammomys obesus and the desert jird Meriones shawi are the principal reservoir hosts of L. major. The presence of the P. papatasi vector of the L. major etiologic agent of ZCL was assessed in the vicinity of villages in endemic areas of Central Tunisia. The study was performed from September through October 2019, a period corresponding to the main peak of activity of P. papatasi. Sand flies were collected from rodent burrows located at the ecotone level, which is the transition zone between the natural environment and human settlement. Sand flies were identified to species level and tested for the presence of L. major by PCR. Our entomological survey showed that P. papatasi is the most abundant sand fly species associated with rodent burrows, and this abundance is even higher in ecotones primarily occupied by P. obesus in comparison to ecotones occupied by M. shawi. Infections with Leishmania major were detected only in P. papatasi, with an overall minimum infection rate (MIR) of 2.64%. No significant difference was observed between the MIRs in ecotones of P. obesus and of M. shawi. Incidence of ZCL in the studied areas ranged from 200 to 700 cases per 100,000 inhabitants, with a mean incidence of 385.41 per 100,000. Higher ZCL incidence was identified in ecotones of M. shawi compared to ecotones of P. obesus. ZCL cases are positively correlated with the MIRs. Considering the short flight range of P. papatasi, increases in its densities associated with burrows of P. obesus or M. shawi at the ecotone level expand the overlap of infected vectors with communities and subsequently increase ZCL incidence. Therefore, control measures should target P. papatasi populations at the ecotones.

Household knowledge, practice and treatment seeking behaviors towards cutaneous leishmaniasis in the endemic rural communities of Ganta- afeshum district, Tigrai, northern Ethiopia, 2019: a cross-sectional study

BackgroundCutaneous leishmaniasis is endemic to Ethiopia. However, the prevention and control efforts of leishmaniasis remain unfocused with clear knowledge and practice gaps within the country. Thus, a house to house survey has been carried out to assess the knowledge, practice and treatment-seeking behavior of households towards cutaneous leishmaniasis in the rural communities of Tigrai region, northern Ethiopia.MethodsA community-based cross-sectional house-to-house survey was conducted in two selected rural villages of Ganta-afeshum district, Tigrai, northern Ethiopia in 2019. A simple random sampling technique was employed to select the participants. Household heads were interviewed using a pre-tested semi-structured questionnaire. Epi info version 7.0 was used for data entry and the data were imported to SPSS version 23 for analysis. Chi-square test (χ2) was used to test the association between the independent variables and the knowledge and practice status of the study participants. P-value < 0.05 was used to declare a statistically significant association among the variables.ResultsIn our study, most of the participants (78%) stated that cutaneous leishmaniasis is a health problem in the area. Three hundred eighty (99.5%) participants responded that the most common clinical presentation of cutaneous leishmaniasis is a lesion on the face. All of the study participants did not know the mode of cutaneous leishmaniasis transmission, and had never heard of the sand fly. A majority of the participants were unaware of the main prevention methods for cutaneous leishmaniasis. Lastly, traditional medicine was used in 90% of the study households with a previous history for cutaneous leishmaniasis.ConclusionThere is a lack of awareness regarding the transmission of cutaneous leishmaniasis in Ganta-afeshum, Ethiopia, where the majority of individuals are unfamiliar with the sand fly vector. Prevention methods for cutaneous leishmaniasis were unavailable among the community. Therefore, health education programs concerning cutaneous leishmaniasis transmission, prevention, and treatment in the area should be rigorously implemented.

DNA barcoding of Lutzomyia longipalpis species complex (Diptera: Psychodidae), suggests the existence of 8 candidate species

The sand fly Lutzomyia (L.) longipalpis has been implicated as the primary vector of Leishmania infantum, the causative agent of visceral leishmaniasis VL. In addition, it has been associated with atypical cutaneous leishmaniasis transmission in the Neotropic and Central America, respectively. The existence of a L. longipalpis complex species has been suggested with important implications for leishmaniasis epidemiology; however, the delimitation of species conforming it remains a topic of controversy. The DNA Barcoding Initiative based on cox1 sequence variation was used to identify the MOTUs in L. longipalpis including previously described L. pseudolongipalpis. The genetic variation was analyzed based on tree and distance methods. Fifty-five haplotypes were obtained from 103 sequences which were assigned to MOTUs, with a clear separation and a high correspondence of individuals to the groups. Maximum likelihood and Bayesian phylogenetic analysis showed eight MOTUs (100% bootstrap) with high genetic divergence (12.6%). Data obtained in the present study suggest that L. longipalpis complex consists of at least 8 lineages that may represent species. It would be desirable perform additional morphological and molecular analysis of L. longipalpis from Colosó (Caribbean ecoregion) considering that specimens from that area were grouped with L. pseudolongipalpis one of the complex species previously described from Venezuela, which has not been registered in Colombia.

The Impact of Illegal Waste Sites on the Transmission of Zoonotic Cutaneous Leishmaniasis in Central Tunisia

Illegal waste disposal represents a risk health factor for vector-borne diseases by providing shelter for rodents and their ectoparasites. The presence of the Phlebotomus papatasi vector of Leishmania major, an etiologic agent of zoonotic cutaneous leishmaniasis (ZCL), was assessed at illegal waste sites located at the vicinity of villages in endemic areas of Central Tunisia. The study was performed over a two-year period over three nights from July to September 2017, and over three nights in September 2018. Household waste is deposited illegally forming dumpsites at the vicinity of each village and contains several rodent burrows of Psammomys obesus, the main reservoir host of L. major. Sandflies were collected from rodent burrows in the natural environment and in dumpsites using sticky traps and were identified at species level. Female sandflies were tested for the presence of L. major by PCR. Our entomological survey showed that Phlebotomus papatasi is the most abundant sandfly species associated with rodent burrows in these waste sites. The densities of P. papatasi in dumpsites are significantly higher compared to the natural environment. The minimum infection rate of P. papatasi with L. major in these illegal waste sites is not significantly different compared to the natural environment. Considering the short flight range of P. papatasi, increases in its densities, associated with burrows of P. obesus in illegal waste sites located at the edge of villages, expands the overlap of infected ZCL vectors with communities. Thus, illegal waste sites pose a high risk of spreading ZCL to neighboring home ranges. Waste management is an environmentally friendly method of controlling sandfly populations and should be included in an integrated management program for controlling ZCL in endemic countries.

Land use in relation to composition and abundance of phlebotomines (Diptera: Psychodidae) in five foci of domiciliary transmission of cutaneous leishmaniasis in the Andean region of Colombia

American cutaneous leishmaniasis is a public health concern in Colombia, its incidence being sustained or focally increased principally by the emergence of domestic transmission concomitantly with the adaptation of the phlebotomine vectors to habitat transformation around households. The objective of the study is to scale up a rapid characterization methodology for evaluating the relationship of land use around the house to the composition and abundance of phlebotomines. Five sites with a history of domestic leishmaniasis transmission in the Andean area of Colombia were selected. The peri-domestic habitat was evaluated at 10 m intervals along eight radial transects, centered on each house, at 45° intervals using a web pattern. Phlebotomines were captured by placing three CDC light traps over two nights both indoors and outdoors (10 m from the house). Blood source and infection were determined by PCR. Spearman rank correlation coefficients and negative binomial regression were used to quantify associations between the phlebotomine abundance and habitat categories. The study demonstrated that the vectors were largely anthropophagic (62% of 79 were human blood) and that a single species in each site was favored by the pertaining agriculture monoculture. Specifically, Pintomyia (Pifanomyia) quasitownsendi was associated with sugar cane in Novillero and La Esmeralda; while Pi. (Pif.) longiflocosa was associated with coffee plantations in Agua Bonita and El Cucal. Honda Alta had a more diverse array of land use and forest coverage with a lower number of specimens but higher species diversity. In terms of distance from the house to an area of a given land use, the abundance of Pi. (Pif.) quasitownsendi was inversely related to the distance to sugar cane plantation (Spearman correlation coefficient, ρ = -0.56, p < 0.001 for outdoor catches, and ρ = -0.50, p < 0.001 indoors). A similar inverse relationship was observed for Pi. (Pif.) longiflocosa with regard to technified coffee (ρ = -0.51, p < 0.001 outdoors, and ρ = -0.48, p < 0.001 indoors).This rapid characterization methodology could guide public heath decision makers in identifying those houses at higher risk of domestic transmission, and also educate farmers to increase the distance between their crops and any neighboring houses.

Association of Phlebotomus guggisbergi with Leishmania major and Leishmania tropica in a complex transmission setting for cutaneous leishmaniasis in Gilgil, Nakuru county, Kenya.

BackgroundPhlebotomus (Larroussius) guggisbergi is among the confirmed vectors for cutaneous leishmaniasis (CL) transmission in Kenya. This scarring and stigmatizing form of leishmaniasis accounts for over one million annual cases worldwide. Most recent CL epidemics in Kenya have been reported in Gilgil, Nakuru County, where the disease has become a public health issue. However, little is known about the factors that drive its transmission. Here, we sought to determine the occurrence, distribution and host blood feeding preference of the vectors, and to identify Leishmania species and infection rates in sandflies using molecular techniques. This information could lead to a better understanding of the disease transmission and improvement of control strategies in the area.Methodology/ Principal findingsAn entomological survey of sandflies using CDC light traps was conducted for one week per month in April 2016, and in June and July 2017 from five villages of Gilgil, Nakuru county; Jaica, Sogonoi, Utut, Gitare and Njeru. Sandflies were identified to species level using morphological keys and further verified by PCR analysis of cytochrome c oxidase subunit I (COI) gene. Midguts of female sandflies found to harbour Leishmania were ruptured and the isolated parasites cultured in Novy-MacNeal-Nicolle (NNN) media overlaid with Schneider’s insect media to identify the species. Leishmania parasite screening and identification in 198 randomly selected Phlebotomus females and parasite cultures was done by PCR-RFLP analysis of ITS1 gene, nested kDNA-PCR and real-time PCR-HRM followed by sequencing. Bloodmeal source identification was done by real-time PCR-HRM of the vertebrate cytochrome-b gene. A total of 729 sandflies (males: n = 310; females: n = 419) were collected from Utut (36.6%), Jaica (24.3%), Sogonoi (34.4%), Njeru (4.5%), and Gitare (0.1%). These were found to consist of nine species: three Phlebotomus spp. and six Sergentomyia spp. Ph. guggisbergi was the most abundant species (75.4%, n = 550) followed by Ph. saevus sensu lato (11.3%, n = 82). Sandfly species distribution across the villages was found to be significantly different (p<0.001) with Jaica recording the highest diversity. The overall Leishmania infection rate in sandflies was estimated at 7.07% (14/198). Infection rates in Ph. guggisbergi and Ph. saevus s.l. were 9.09% (12/132) and 3.57% (2/56) respectively. L. tropica was found to be the predominant parasite in Gilgil with an overall infection rate of 6.91% (13/188) in Ph. guggisbergi (n = 11) and Ph. saevus s.l. (n = 2) sandflies. However, PCR analysis also revealed L. major infection in one Ph. guggisbergi specimen. Bloodmeal analysis in the 74 blood-fed sandflies disclosed a diverse range of vertebrate hosts in Ph. guggisbergi bloodmeals, while Ph. saevus s.l. fed mainly on humans.Conclusions/ SignificanceThe high infection rates of L. tropica and abundance of Ph. guggisbergi in this study confirms this sandfly as a vector of L. tropica in Kenya. Furthermore, isolation of live L. tropica parasites from Ph. saevus s.l. suggest that there are at least three potential vectors of this parasite species in Gilgil; Ph. guggisbergi, Ph. aculeatus and Ph. saevus s.l. Molecular identification of L. major infections in Ph. guggisbergi suggested this sandfly species as a potential permissive vector of L. major, which needs to be investigated further. Sandfly host preference analysis revealed the possibility of zoonotic transmissions of L. tropica in Gilgil since the main vector (Ph. guggisbergi) does not feed exclusively on humans but also other vertebrate species. Further investigations are needed to determine the potential role of these vertebrate species in L. tropica and L. major transmission in the area.

Abundancia y diversidad de vectores (Diptera: Psychodidae) en área de transmisión antigua de Leishmaniasis Cutánea en el nuevo mundo después de la construcción del gasoducto Bolivia-Brasil

The objective of this study was to determine the abundance and diversity of the species and their presumed vectorial role in the transmission of Cutaneous Leishmaniasis (CL). Research on sand flies (Diptera: Psychodidae) was carried out in two municipalities in the Ribeira River Valley in the State of Parana, southern Brazil. One, Adrianopolis, is an endemic area of CL and the other is a recent outbreak area (Cerro Azul). A total of 432 specimens were collected from residential, peri-domestic and wild environments. According to the data obtained, for each ecotope studied, the statistical analysis has shown that two lines of the Lutzomyia intermedia population coexist and that the quantity of specimens from L. intermedia s.l . is significantly different from L. intermedia s.s . in all environments (χ 2 =9.943; DF=2; p=0.07). The prevalence of L. intermedia (93.28%) in the ecotopes studied suggests that it is the main vector of leishmaniasis. The succession of vector species and their involvement in the epidemiological cycle of L. braziliensis is discussed in this article.