Transmission Of Leishmaniasis Research Articles

CRISPR/Cas9 gene drive technology to control transmission of vector-borne parasitic infections.

Gene drive is the process of copying of an endonuclease-containing cassette that leads to increased frequency of inheritance of the desired traits in a targeted population. CRISPR/Cas9 technology is advancing genetic manipulation of insects in the field of gene drive experiments. The CRISPR/Cas9 drive could be engineered for genetic manipulation of parasites and/or vectors for disease control. A number of promising CRISPR/Cas9-based gene drive strategies that interfere with parasite development or impairs the reproductive capability of the insect vector have been proposed in the laboratory for blocking transmission of malaria and leishmaniasis. Still several technical and ethical challenges remain to be addressed, and none appear insuperable in this field.

Complex ecological interactions across a focus of cutaneous leishmaniasis in Eastern Colombia: novel description of Leishmania species, hosts and phlebotomine fauna

This study aimed to analyse the patterns of diversity, blood sources and Leishmania species of phlebotomines in a focus of cutaneous leishmaniasis in Arboledas, Eastern Colombia. In total, 1729 phlebotomines were captured in two localities (62.3% Siravita and 37.7% Cinera) and five environments of Norte de Santander. We identified 18 species of phlebotomines: Pintomyia ovallesi (29.8%), Psychodopygus davisi (20.3%), Pi. spinicrassa (18.5%) and Lutzomyia gomezi (15.8%) showed the highest abundance. Species diversities were compared between Cinera (15.00) and Siravita (20.00) and among five microenvironments: forest remnants (19.49), coffee plantations (12.5), grassland (12.99), cane plantations (11.66) and citrus plantations (12.22). Leishmania DNA was detected in 5.8% (80/1380) of females, corresponding mainly to Pi. ovallesi (22/80; 27.2%), Lu. gomezi (17/80; 21.3%) and Pi. spinicrassa (11/80; 13.8%). Leishmania species were 63.1% L. braziliensis, 18.5% L. panamensis, 13.2% L. infantum and 6.1% L. amazonensis. The most frequent feeding sources were Homo sapiens (50%), Bos taurus (13.8%) and Canis lupus familiaris (10.3%). This focus of cutaneous leishmaniasis has a high diversity of Leishmania-carrying phlebotomines that feed on domestic animals. The transmission of leishmaniasis to human hosts was mainly associated with Lu. gomezi, Pi. ovallesi and L. braziliensis.

Conversion of asymptomatic infection to symptomatic visceral leishmaniasis: Astudy of possible immunological markers.

IntroductionPresence of asymptomatic individuals in endemic areas is common. The possible biomarkers in asymptomatic individuals once they get exposed to infection as well as following conversion to symptomatic disease are yet to be identified.We identified asymptomatic Visceral leishmaniasis (VL) infection amongst rK39+sorted direct agglutination test positive (DAT+) endemic healthy population and confirmed it by quantitative PCR(qPCR).The immunological determinants such as Adenosine deaminase (ADA), Interferon gamma (IFN-γ), Tumour Necrosis Factor alpha (TNF-α) and Interleukin 10 (IL-10)were examined to predict probable biomarkers for conversion to symptomatic VL.MethodsSample size was 5794 healthy individuals from VL endemic region. Antibody tests(DAT &rK39) were performed and later a qPCR assay was employed using kDNA specific primers and probes. Immunological biomarkers examined were ADA level by ADA–MTP kit and quantitative cytokines(IFN-γ, IL-10 and TNF-α) by ELISA.Results120 asymptomatic individuals of 308 rK39 sero-positives were DAT positive comprising of 56 with previous history and 64 with no history of VL. RT-PCR confirmed asymptomatic VL in 42 sero-positives. These were followed up through repeated qPCR and evaluation of immunological determinants. We observed10 symptomatic cases converted from a total of 42 asymptomatic individuals identified at base-line. The level of ADA, IL-10 and IFN-γ remained consistently high in asymptomatic cases and amongst these, ADA and IL-10 but not IFN-γ remained higher at the development of clinical symptoms into active VL. On the contrary, there was no significant change in the mean concentration of TNF-α at both stages of the disease.DiscussionWe surmise from our data that considerable proportion of asymptomatic cases can be a reservoir and may play a crucial role in transmission of visceral leishmaniasis in endemic areas.The data also suggests that ADA and IL-10 can serve as a potential biomarker during the conversion of asymptomatic into symptomatic VL.

Percepções dos profissionais de saúde do município de Sousa-PB sobre leishmaniose visceral

<p class="Normal1">The objective of this study was to analyze the knowledge of health professionals in Sousa’s basic care units about Visceral Leishmaniasis. 100 epidemiological questionnaires were applied with Community Health Agents, Nursing Technicians, Nurses and Doctors. It was observed that, among the 100 professionals interviewed, 88% stated that Leishmaniasis is a zoonosis, 97% know Leishmaniasis by the name of Kala-azar. Regarding the transmission of Leishmaniasis, 80% of professionals believe that it happens through the bite of the infected mosquito. However, only 78% of professionals recognize that the etiological agent is protozoan. In relation to the treatment for Leishmaniasis, 100% of the professionals interviewed believe that there is treatment for this disease, and 90% mentioned that there was a cure. About the existence of a vaccine, 69% said it did not exist. Regarding control and prophylaxis measures, 34% refer to diagnostic tests on people and animals. In relation to the prevention of Leishmaniasis, 65% of professionals gave their opinion on preventing the spread of the mosquito and informing preventive measures. It is concluded that there are still conceptual gaps in health professionals in the municipality of Sousa - PB, about Visceral Leishmaniasis, with the need to implement permanent education processes for these professionals, contextualizing the information about leishmaniasis to the studied reality.</p>

Effects of forest degradation on the sand fly communities of northeast Brazil.

The richness and abundance of sand fly species were studied in northeastern Brazil in areas of leishmaniasis transmission. The study was carried out in two forest areas with different deforestation times for agricultural and livestock activities: one modified by long-term settlement (more than 50 years of occupation) and another less impacted by short-term settlement (10 years). The sand flies were captured with CDC light traps from 18:00 to 06:00 for three consecutive nights, once a month, from May, 2012 to April, 2014. The study captured 21,708 specimens and also 33 species of Lutzomyia and two of Brumptomyia. Species richness and abundance were higher in the more conserved area of short-term occupation (31 species; 61.7%) than in the more degraded area with long-term occupation (17 species; 38.3%). In the most conserved area, the species richness was higher in the forest fragment than in the rural settlement, whereas in the degraded area the richness was higher in the peri-domicile than in the forest. The diversity was higher in the degraded area forest. There were significant statistical differences when comparing the means of total abundance with the intra-domicile, peri-domicile, and forest environments. The average abundance was statistically higher in the peri-domicile compared to the forest (p = 0.009), but there were no statistically significant differences between intra-domicile-peri-domicile (p = 0.11) and forest-intra-domicile (p = 0.87). In conclusion, a change in vegetation cover negatively affects the richness and abundance of sand flies in the natural environment.

Exploring Lutzomyia longipalpis Sand Fly Vector Competence for Leishmania major Parasites.

Lutzomyia longipalpis sand flies are the major natural vector of Leishmania infantum parasites, responsible for transmission of visceral leishmaniasis in the New World. Several experimental studies have demonstrated the ability of Lu. longipalpis to sustain development of different Leishmania species. However, no study had explored in depth the potential vector competence of Lu. longipalpis for Leishmania species other than L. infantum. Here, we show that Lu. longipalpis is a competent vector of L. major parasites, being able to acquire parasites from active cutaneous leishmaniasis lesions, sustain mature infections, and transmit them to naive hosts, causing disease.

Modeling Spatial Distribution of Sergentomyia minuta (Diptera: Psychodidae) and Its Potential Implication in Leishmaniasis Transmission in Morocco.

Background:Leishmaniases are parasitic diseases caused by Leishmania species and transmitted by the bite of sand flies. The genus Lutzomyia and Phlebotomus of sand flies are known to be the responsible vector for transmitting almost all Leishmania species to humans. The detection of Leishmania DNA in species of the genus Sergentomyia, in different regions, suggests their likely role in Leishmania transmission.Methods:Our objective was to determine the potential geographical distribution of Sergentomyia minuta, the most dominant Sergentomyia species in Morocco, using ecological niche modeling.Results:The results showed the widespread geographical distribution of S. minuta in Morocco, specifically in northern and central Morocco where visceral and cutaneous leishmaniasis foci occur. There were six abiotic factors affecting the distribution of S. minuta whose annual precipitation, precipitation seasonality and precipitation of driest month as the most important ecological variables of the model.Conclusion:A positive statistical correlation between human leishmaniasis cases and S. minuta abundance was noted suggesting the potential involvement of S. minuta in local Leishmania transmission cycles.

Housing structure including the surrounding environment as a risk factor for visceral leishmaniasis transmission in Nepal.

Visceral leishmaniasis (VL) in Nepal is found in 61 out of 75 districts including areas previously listed as non- endemic. This study focused on the role of housing conditions and its immediate environment in VL transmission, to limit future transmissions, ensure sustainable vector control and support the VL elimination program. The objective was to explore the risk factors in rural housing-and land lot typologies contributing to clinical VL occurrence and transmission. Housing structures and land lots were examined based on characteristics as risk factors of VL transmission in a case-control analysis. VL cases from 2013-2017 were identified based on the existing database from the Epidemiology and Disease Control Division and District Public Health Office from the plain Terai area (Morang, and Saptari districts) and hilly area (Palpa district) of Nepal. Two hundred and three built environments were analyzed (66 cases and 137 controls). Inferential statistics and logistic regression analysis were performed to determine the association of risk factors with VL. The risk factors with the highest odds of VL were: bamboo walls (adjusted odds ratio (AOR)- 8.1, 95% CI 2.40-27.63, p = 0.001), walls made of leaves/branches (AOR- 3.0, 95% CI 0.84-10.93, p = 0.090), cracks in bedroom walls (AOR- 2.9, 95% CI 0.93-9.19, p = 0.065), and placing sacks near sleeping areas (AOR- 19.2, 95% CI 4.06-90.46, p <0.001). Significant outdoor factors were: lots with Kadam trees (AOR- 12.7, 95% CI 3.28-49.09, p <0.001), open ground-outdoor toilets (AOR- 9.3, 95% CI 2.14-369.85, p = 0.003), moisture in outdoor toilet sheds (AOR- 18.09, 95% CI 7.25-451.01, p = 0.002), nearby- open land (AOR- 36.8, 95% CI 3.14-430.98, p = 0.004), moisture inside animal sheds (AOR- 6.9, 95% CI 1.82-26.66, p = 0.005), and surrounding animals/animals wastes particularly goats (AOR- 3.5, 95% CI 1.09-10.94, p = 0.036). Certain housing and surrounding environmental conditions and characteristics are risk factors for VL. Hence, elimination and educational programs should include the focus on housing improvement and avoidance of risk factors. Longitudinal interventional studies are required to document temporal relationships and whether interventions on these factors will have an impact on Leishmania transmission or burden.

A rare encounter in nonsuspecting circumstances: First congenital visceral leishmaniasis (kala-azar) in Libya

Congenital transmission of Leishmaniasis is very rare. It occurs through blood exchange from the mother to the child during pregnancy or delivery. We report the first confirmed congenital leishmaniasis in a 4-month-old Libyan boy with prolonged jaundice and hepatosplenomegaly. This was a congenital transmission from his mother who was asymptomatic and not known to have leishmaniasis, which was confirmed after the diagnosis of the infant. Despite treatment, the infant died. The diagnostic approach is illustrated by the case report. Poor obstetric history in the mother may be related to her own undiagnosed kala azar.

Ecology of Leishmaniasis in an urbanized landscape: Relationship of sand fly densities, and Leishmania tropica infection rates with reservoir host colonies

Urbanization may influence the transmission of leishmaniasis, which is as a serious public health issue in Palestine. Semi urban environments can provide suitable habitats for the reservoir host species and the vector sand flies to create favorable condition for disease transmission. This study was aimed to evaluating the effect of distance from hyrax (reservoir host) colonies on sand fly (vector) abundance and its relationship to Leishmania infection within a semi urban landscape. In the Aleskan neighborhood the town of Tubas, sand flies were collected in July and September of 2016. Five trapping transects were set running from a rocky area containing hyrax dwelling habitats into an area of inhabited houses. 1051 Phlebotomus sand flies from 9 species were captured. The numbers of Phlebotomus sergenti, the vector species, correlated negatively with the distance from hyrax. Infected, blood engorged female sand flies were captured closer to hyrax colonies than infected, non-fed females. The risk of disease transmission to humans increased with a high density of reservoirs, closer proximity of reservoir hosts, and high densities of sand flies near houses. These results must be taken into account when implementing future interventions to reduce CL in urban environments.

Transmission of Leishmania infantum from cats to dogs

Leishmania infantum infection in cats has been reported in several countries, including Brazil. However, the transmission of visceral leishmaniasis (VL) from cats to another host has not been proven yet. Therefore, the aim of this study was to verify the possibility of L. infantum transmission from cats to dogs. In order to verify the possibility of VL transmission from the cat to the dog, xenodiagnosis was carried out in a VL-positive cat, using 55 female Lutzomyia longipalpis. Five days later, 40 insects were dissected to verify Leishmania infection. The remaining 15 females were fed in a healthy dog. The potential infection of the dog was verified through clinical, serological, parasitological examinations, and PCR, at three, six, and twelve months post-infection. All 55 L. longipalpis females became visibly engorged. Leishmania promastigotes were detected in 27.5% of the dissected insects. Leishmania infection in the dog was confirmed upon first evaluation. DNA sequencing of the parasite isolated from the cat confirmed L. infantum infection and showed 99% similarity with the L. infantum DNA sequences from the dogs. Through this study, it was possible to confirm the L. infantum experimental transmission from a domestic cat to a domestic dog through its biological vector L. longipalpis.

Ecology of phlebotomine sand flies in a Brazilian area with recent leishmaniasis transmission (Itaúna, in Minas Gerais state)

INTRODUCTION: Leishmaniasis constitutes a serious but neglected tropical disease. Recently, socio-environmental, biological and physical changes have altered the range of leishmaniasis, causing it to spread into urban areas. In Minas Gerais, the disease is endemic, exhibiting regional differences and reaching urban centers. The purpose of this study was to evaluate entomological aspects related to the ecoepidemiology of leishmaniasis in Itaúna. METHODS: Monthly catches with HP traps were carried out from June 2017 to May 2018, in three ecological areas (urban, rural, and forest). The adaptability of the species to anthropic environments was assessed using the synanthropy index (SI). RESULTS: We collected 1306 specimens of phlebotomine sand flies. Of the species of medical importance, Lutzomyia longipalpis, the vector of Leishmania infantum, represented 90.4% of the specimens identified at species level (n=1260). Nyssomyia whitmani, the vector of Leishmania braziliensis, represented 1.6% of the total. Lu. longipalpis displayed an SI of +95.8, a value that denotes a marked preference for human environments. For Ny. whitmani, the SI was -25, expressing the tendency of this species to occupy uninhabited areas. The population of the three most numerous species captured increased with rain, high temperatures, and high relative humidity. Although captured at low numbers, Ny. whitmani showed a different profile concerning the climate variables analyzed. CONCLUSIONS: Understanding the epidemiology of the disease may assist the health services in formulating effective control measures for improving community health and contributing to the establishment of a dynamic relationship and a global awareness of the health/disease process.

Sandfly fauna and ecological analysis of Phlebotomus orientalis and Phlebotomus martini in the lowland foci of visceral leishmaniasis in Somali Regional State, southeast Ethiopia

Objective: To identify the sandfly fauna and analyze ecology of sandfly vector(s) of visceral leishmaniasis in three districts of Somali Regional State, southeast Ethiopia. Methods: Sandflies were collected from four sampling habitats, including indoor, peri-domestic, farm field and mixed forest using light and sticky traps in July 2016, and February and April 2017 in Liben and Dawa zones in the Somali Regional State, southeastern Ethiopia. Results: In total, 4 367 sandfly specimens, belonging to 12 species (three Phlebotomus spp. and nine Sergentomyia spp.) were identified. Phlebotomus (P.) heischi, P. orientalis, and P. martini constituted 45.7%, 31.1%, and 23.1% of the sandfly collection, respectively. There were significant differences in the median number of P. orientalis, and P. martini captured per CDC trap/night between the three sampling districts (P Conclusions: The study demonstrated that the presence of P. orientalis and P. martini are probable vectors of visceral leishmaniasis in this new focus. The findings of our study will improve the understanding of the dynamics of visceral leishmaniasis transmission and will facilitate the implementation of integrated disease control measures based on ecological knowledge of visceral leishmaniasis vector in Liben and Dawa zones and its surrounding regions.

Wild mammals as potential silent reservoirs of Leishmania infantum in a Mediterranean area

A molecular survey of wild mammals was performed to assess their potential as reservoirs of L. infantum. A total of 156 specimens of wild mammalian fauna were obtained for analysis from areas in Catalonia with a reported incidence of canine leishmaniasis. They consisted of 124 small mammals: 35 Mus spretus (Muridae); 64 Erinaceus europaeus (Erinaceidae), 25 Sciurus vulgaris (Sciuridae) and 32 carnivores: 11 Vulpes vulpes (Canidae), 1 Felis catus (Felidae), 15 Meles meles, 4 Martes foina and 1 Mustela vison (Mustelidae). The analysis was performed on samples of liver, spleen, skin (ear) and blood extracted from the heart. Leishmania DNA was determined by a qPCR and specific anti-Leishmania antibodies were detected by an in-house (ELISA).Among the 156 specimens studied, 29.48% were positive in at least one of the samples studied and considered infected. In M. spretus, Leishmania DNA was detected in the liver, spleen or skin of 37.1% of 35 specimens, and 2 of the 13 specimens tested serologically were positive (15.38%). In E. europaeus, 34.4% of the 64 specimens were infected. Leishmania DNA was detected in 19/51 spleens and 5/50 skins; 2 of the 37 specimens analysed in both spleen and skin gave positive results in both samples. Serology was positive in 12.8% (6/47) by ELISA; 3 specimens were positive by both ELISA and qPCR. In S. vulgaris, Leishmania DNA was detected in 5 of 25 specimens (20%). Of the 32 carnivore specimens analysed, Leishmania DNA was detected in both samples studied (spleen and liver) of 4 (12.5%) (2 M. foina, 1 M. vison and 1 F. catus), which were not studied serologically.The data obtained indicate that small mammals, above all wild rodents and carnivores, could act as naturally infected hosts of L. infantum in this endemic area. Among the rodents, M. spretus stands out with the highest prevalence of infection. In E. europaeus, the presence of L. infantum DNA in spleen and skin, and antibodies in heart blood, reported here for the first time, indicates this small mammal could be a possible reservoir. Additionally, S. vulgaris, not previously studied as an L. infantum reservoir, showed non-negligible prevalence values, indicating a potential role in leishmaniasis transmission.

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.

Serological and molecular investigation of Leishmania spp. infection in cats from an area endemic for canine and human leishmaniasis in Northeast Brazil.

The aim of this study was to investigate the occurrence of Leishmania spp. antibodies, and its association with feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV), in domestic cats from an area endemic for canine and human leishmaniasis in Rio Grande do Norte State, Brazil. Ninety-one cats were subjected to a complete clinical exam, and blood samples were collected. An epidemiological questionnaire was used to investigate the risk factors. IgG anti-Leishmania spp. antibodies were detected by immunofluorescence antibody test (IFAT), with a cut-off value of 1:40. Polymerase chain reaction (PCR) was performed to detect genetic material of Leishmania spp. in the blood samples. The presence of antibodies against FIV and antigens of FeLV was evaluated using an immunochromatographic test. Seropositivity for Leishmania spp., FIV, and FeLV was observed in 14/91 (15.38%), 26/91 (28.57%), and 3/91 (3.29%) cats, respectively. All samples gave negative results on PCR analysis. Based on these data, no significant statistical association was observed between seropositivity for Leishmania spp., and sex, age, presence of clinical signs, evaluated risk factors, and positivity for retroviruses. These findings demonstrated for the first time that cats from Mossoró, Rio Grande do Norte, are being exposed to this zoonosis and might be part of the epidemiological chain of transmission of visceral leishmaniasis.

Eco-epidemiological study on sandflies and environmental aspects related to the transmission of leishmaniasis in a municipality of Minas Gerais, Brazil, 2015-2016

ABSTRACT The aim of this study was to evaluate Leishmania vectors and investigate the environmental and climatic characteristics related to their transmission. This was a prospective eco-epidemiological study involving the systematic collection of sandflies and a canine serological survey in areas of municipality in Brazil. Blood samples from 1,752 dogs were examined to test for canine visceral leishmaniasis (VL). An entomological evaluation was carried out using 24 light traps in the peridomicile and intradomicile areas of 12 households for 12 months. Climate variables were analyzed using a simple Spearman correlation and a spatial analysis via the fuzzy logic method and K function. The prevalence rate of canine VL was 4.1% and 7.1% in the two areas that were studied, respectively. The entomological study resulted in the capture of 431 sandflies. Most (74%) of the specimens were captured in the peridomiciliary area, and 5.6% of the samples that were analyzed using molecular biology were positive for Leishmania spp. In particular, Leishmania infantum was found in 100% of the positive samples. The spatial analysis showed that one particular area presented a higher concentration of high-density overlapping points of Lutzomyia longipalpis and seropositive dog populations, indicating a higher risk of the concomitant occurrence of both events. The results show that a parasite-reservoir-vector interface is active in the studied areas.

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.

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

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

Effectiveness of the mass use of deltamethrin-impregnated dog collars for preventing transmission of canine leishmaniasis by Lutzomyia spp.: A cluster randomized controlled trial

Visceral leishmaniasis (VL) is a zoonosis that greatly impacts public health, especially in developing countries. The effectiveness of deltamethrin-impregnated dog collars for preventing transmission of canine leishmaniasis (CanL) by the sand fly Lutzomyia spp. in countries with high incidence of the disease, such as Brazil, remains unknown. A cluster randomized controlled trial was carried out to evaluate the effectiveness of these collars in preventing infection of dogs with Leishmania infantum.Two areas were selected in a municipality endemic for VL in Brazil: an experimental area (EA) and a control area (CA). In both areas, blood samples were collected from dogs for detection of CanL. Seronegative dogs from the EA received collars impregnated with deltamethrin 4%. After six months, the dogs were retested for CanL and the incidence of the disease, the relative risk, and the effectiveness of collaring determined. In the baseline survey, 1020 dogs from the EA and 589 from the CA were examined. The prevalence calculated for EA was 4.41% (CI95% 3.27–5.91), and 7.13% (CI95% 5.25–9.59) for CA. In the second evaluation, 454 dogs from the EA and 292 from the CA were examined. The person-time incidence calculated for EA was 3.51% (CI95% 1.30–7.48), and for CA was 11.81% (CI95% 7.03–18.23). The difference between the calculated incidences was statistically significant (p = 0.009). The relative risk was 0.2972 (CI95% 0.1204-0.7339; p = 0.009), and the efficacy of the proposed measure was estimated in 70.27%.This report evaluated the effectiveness of the mass use of deltamethrin-impregnated dog collars in areas of transmission of VL by Lutzomyia spp. Collaring was able to protect dogs and may represent an effective strategy that could be implemented to control infection in both dogs and humans in Brazil and perhaps other countries where Lutzomyia spp. is the main vector of the disease.