Phlebotomine sand flies (Diptera: Psychodidae) associated with the appearance of urban leishmaniasis in the city of Sincelejo, Colombia

Incriminating leishmaniases vectors in Colombia: An overview and roadmap for future research

A major challenge in defining the vector status of phlebotomine sand flies is selecting the appropriate criteria. Vectors can be graded by importance, with successful transmission as the highest grade. Potential vectors are often identified based on high frequency in transmission foci, anthropophily, and more recently by identification of DNA in field samples. However, a species' ability to transmit a pathogen depends not only on its intrinsic biology of sand fly-Leishmania interactions but also on ecological parameters, which are rarely evaluated. This study aimed to analyze the literature data describing characteristics of Colombian sand flies related to their role as vectors of Leishmaniinae parasites. Based on information contained in scientific publications using combinations of five criteria, sand fly species were graded into five levels, and 26 species were considered as potential or proven leishmaniasis vectors in Colombia. Levels one to four refer to potential or suspected status, while level five denotes proven vectors. Studying vectors in a regional context is crucial because species' behaviors vary with environmental and ecological conditions, meaning a species may be a key vector in one area but not in another. A better understanding of vector-parasite interactions will aid in developing innovative control strategies and formulating significant epidemiological perspectives.

Phlebotomine (Diptera: Psychodidae) species and their blood meal sources in a new leishmaniasis focus in Los Montes de María, Bolívar, in northern Colombia

Introduction. El Alférez, a village in Los Montes de María (Bolívar, Colombia) and a macro-focus of leishmaniasis, recorded its first case in 2018, evidencing changes in the distribution and eco-epidemiology of the disease, although interactions between vectors and local fauna remain unknown. Objective. To evaluate the diversity of sandflies and their blood meal sources in the community of El Alférez in the municipality of El Carmen de Bolívar (Bolívar, Colombia). Materials and methods. In 2018, sandflies were collected using LED-based light traps in domestic, peridomestic, and sylvatic ecotopes and identified at the species level. Multiplex polymerase chain reaction targeting the mitochondrial cytochrome B gene was used to analyze blood from the digestive tract. Results. Lutzomyia evansi was the most abundant species (71.85%; n = 485/675), followed by Lu. panamensis, Lu. gomezi, Lu. trinidadensis, Lu. dubitans, Lu. abonnenci, and Lu.aclydifera. Twenty-five percent of the species had blood meals from Canis familiaris (36.00%; n = 9/25), Ovis aries (36.00%; n=9:/25), Bos taurus (24.00%; n = 6/25), Sus scrofa (20.00%; n = 5/25), and Homo sapiens (8.00%; n = 2/25). Lutzomyia evansi registered the highest feeding frequency (68.00%; n = 17/25), predominantly on a single (44.00%; n = 11/25) or multiple species (24.00%; n = 6/25). Conclusion. Results indicate a eclectic feeding behavior in Lu. evansi, implying potential reservoir hosts for Leishmania spp. and increasing transmission risk. This study is a first step towards understanding the diversity of mammalian blood sources used by sandflies, that may be crucial for vector identification and formulation of effective control measures.

[Circulación de Leishmania infantum y Trypanosoma cruzi en perros domésticos de áreas urbanas de Sincelejo, región Caribe de Colombia]

Introducción. La enfermedad de Chagas y la leishmaniasis tradicionalmente se han considerado zoonosis endémicas de áreas rurales del país. Sin embargo, la aparición de casos de estas enfermedades en áreas urbanas sugiere nuevos ciclos de circulación de estos parásitos. Por esta razón, se ha propuesto a los perros como centinelas de estos agentes zoonóticos, dado su rol como huéspedes accidentales o reservorios. Objetivo. Evaluar la circulación silenciosa de Leishmania spp. y Trypanosoma cruzi en perros de zonas urbanas de la ciudad de Sincelejo, Sucre. Materiales y métodos. Se analizaron 100 muestras de sangre de perros para amplificar la región ITS1 de Leishmania spp. Las muestras positivas se utilizaron para amplificar la región conservada del minicírculo del ADN del cinetoplasto de Leishmania infantum y para el análisis de polimorfismos de longitud de fragmentos de restricción con la endonucleasa HaeIII. Por otra parte, se amplificó un fragmento del ADN satelital de T. cruzi. Además, se evaluó la presencia de infecciones por Ehrlichia canis y Anaplasma platys, como potencialmente modificadoras de las manifestaciones clínicas. Resultados. De los 100 perros estudiados, se detectó: Leishmania spp. en 32, T. cruzi en 12, ambos parásitos en 7 y L. infantum en 18. Se encontraron infecciones por anaplasmatáceos en 18, y coinfecciones por bacterias y parásitos en 8 de los perros. En general, 47 de los animales estaban infectados por, al menos, un agente etiológico. Conclusión. Se demuestra la circulación de L. infantum y T. cruzi en zonas urbanas de Sincelejo, así como coinfecciones de estos parásitos junto con parásitos de la familia Anaplasmataceae. El presente estudio demuestra la conveniencia del uso de perros en la vigilancia epidemiológica de estos agentes zoonóticos.

Effect of land use change on the phlebotomine sand fly assemblages in an emergent focus of cutaneous leishmaniasis in Yucatan, Mexico

As land use intensifies in tropical forests, it is expected that species assemblages will be modified and that key functions of these ecosystems will be affected. The latter scenario is important from a public health perspective, because the land use change has been linked the outbreaks of vector-borne diseases. In this study, we evaluated the response of Phlebotominae (Diptera: Psychodidae) assemblages and their pattern of co-occurrence in four sites with different land use in an emerging cutaneous leishmaniasis focus in Yucatan, Mexico. Our hypothesis is that the conservation status (as forest cover) will positively influence the structure and composition of sand flies' assemblages. Using three different traps over a period of five months, a sampling effort of 1, 440 night-traps was performed. A total of 7, 897 sand fly specimens belonging to six genera and 10 species were collected. Our hypothesis was partially achieved since sand fly diversity increased as forest cover increased and vice versa, however random patterns of co-occurrence in assemblages were detected among sites. Even though the high abundance of sand flies in the forest fragment suggests an amplification effect, our results show that different vector species directly dominate in each site. We discuss the potential implications of the nestedness of species dominance. We suggest that in this emerging focus and under the land use gradient, Lutzomyia cruciata and Psathyromyia cratifer could play a pivotal role in maintaining the transmission cycles of Leishmania. The apparent generalist or colonialist profile of Lu. cruciata in disturbed areas deserves attention, due to the potential risk of leishmaniasis "domiciliation". This information is essential to understand the eco-epidemiology of leishmaniasis and the factors associated with its emergence in Yucatan, Mexico.

Pintomyia evansi (Diptera: Psychodidae) larvae susceptibility to hydrated lime under laboratory conditions

This study evaluated the effect of Calcium hydroxide (Ca(OH)₂ Mg(OH)₂) on third stages Pi. evansi larvae mortality under experimental laboratory conditions. Three treatments containing a mixture of phlebotomine natural breeding soil (substrate) and Calcium hydroxide at different concentrations were used: Treatment 1 (T1), 1 kg of substrate mixed with 56.2 g of lime; Treatment 2 (T2), 1 kg of substrate mixed with 62.5 g of lime; and Treatment 3 (T3), 1 kg of substrate mixed with 70 g of lime. in addition, a sample of substrate without lime was used as a control for each treatment. The mortality in T1 was 1% at 24 h and 12% at 48 h, reaching a maximum of 56% at 72 h of exposure. For T2, mortality was progressive, starting with 12% at 12 h, 36% at 24 h, 52% at 48 h, and 100% at 72 h; while T3 showed mortality percentages of 94% and 100% between 12 and 24 h of exposure. Therefore, T3 was the most effective to according to the Kaplan-Meier survival analysis. This study showed that treatments over 62 g of Calcium hydroxide per 1 kg of substrate offer a starting point for immature stage control under laboratory conditions. With these results, we propose to evaluate the cost-effectiveness and feasibility of the application, of the latter concentration, under field conditions in urban environments for its application in vector control programs.

DIVERSIDAD DEL GÉNERO Lutzomyia (Diptera: Psychodidae) EN MUNICIPIOS DEL DEPARTAMENTO DE CÓRDOBA – COLOMBIA

La estimación de los cambios en la diversidad y como se encuentran compuestas las comunidades de insectos en áreas de transmisión, de diferentes zonas de vida, puede indicar patrones diferenciales en la transmisión y fauna de reservorios asociada, así como diferentes escenarios de riesgo epidemiológico. Un ejemplo es la leishmaniasis, parasitosis relacionada con la presencia de flebotomíneos del género Lutzomyia, que en Córdoba (Colombia) presenta áreas de transmisión para las formas cutánea y visceral de leishmaniasis, enmarcadas en diferentes zonas de vida – Holdridge (Bs–T, Bh–T, entre otras). El presente estudio tiene como objetivo estimar la diversidad de los inventarios entomológicos realizados en diferentes zonas con presencia de potenciales vectores de leishmaniasis, en 17 localidades de diez municipios del departamento de Córdoba, entre mayo de 2015 y noviembre de 2016. En total se recolectaron 1695 flebotomíneos representado en 13 especies del género Lutzomyia.  Las especies más abundantes para el departamento de Córdoba son Lutzomyia evansi y Lutzomyia gomezi, con el 30,44 % y 29,62 %, respectivamente. Se reporta por primera vez la presencia de Lutzomyia trapidoi para el territorio cordobés. Con este estudio se amplía el conocimiento de la diversidad del género Lutzomyia en términos de distribución de abundancias, diversidades verdaderas y composición de especies en zonas activas del departamento de Córdoba.

FLEBOTOMÍNEOS (PSYCHODIDAE: PHLEBOTOMINAE) EN LA ZONA PERIURBANA DE MONTERÍA (CÓRDOBA- COLOMBIA)

El objetivo de este trabajo fue determinar la diversidad de flebotomíneos (Diptera: Psychodidae) en la zona peri-urbana de Montería, (Córdoba-Colombia). Los especímenes se colectaron en cuatro localidades alrededor de Montería con trampas CDC y aspiradores bucales durante febrero y junio de 2018. Los individuos se fragmentaron y aclararon con lactofenol para su posterior identificación mediante claves taxonómicas especializadas. Se estimó la diversidad con el índice de Shannon-Wiener, las localidades se compararon usando la distancia de Bray-Curtis y se cuantificó la riqueza con los índices de Chao 2 y Jacknife 2. Se identificaron seis especies: Micropygomyia cayennensis, Lutzomyia gomezi, Pintomyia rangeliana, Micropygomyia micropyga, Psathyromyia shannoni y Pintomyia evansi. Los sitios de muestreo fueron similares en cuanto a diversidad. Se concluye que la zona peri-urbana de Montería está habitada por especies generalistas de dípteros de la familia Psychodidae que constituyen un riesgo epidemiológico. La riqueza en el área se ve afectada por las características propias de las especies encontradas.

Barriers to cutaneous leishmaniasis care faced by indigenous communities of rural areas in Colombia: a qualitative study

BACKGROUND

Neglected tropical diseases (NTDs) such as cutaneous leishmaniasis (CL) are often associated with rural territories and vulnerable communities with limited access to health care services. The objective of this study is to identify the potential determinants of CL care management in the indigenous communities in the rural area of the municipality of Pueblo Rico, through a people-centered approach.

METHODS

To achieve this goal, qualitative ethnographic methods were used, and a coding framework was developed using procedures in accordance with grounded theory.

RESULTS

Three dimensions that affect access to health care for CL in this population were identified: (1) contextual barriers related to geographic, economic and socio-cultural aspects; (2) health service barriers, with factors related to administration, insufficient health infrastructure and coverage, and (3) CL treatment, which covers perceptions of the treatment and issues related to the implementation of national CL treatment guidelines. This study identified barriers resulting from structural problems at the national level. Moreover, some requirements of the national guidelines for CL management in Colombia impose barriers to diagnosis and treatment. We furthermore identified cultural barriers that influence the perceptions and behavior of the community and health workers.

CONCLUSIONS

While the determinants to CL management are multidimensional, the most important barrier is the inaccessibility to CL treatment to the most vulnerable populations and its inadequacy for the socio-territorial setting, as it is not designed around the people, their needs and their context.

Genomic Diversification, Structural Plasticity, and Hybridization in Leishmania (Viannia) braziliensis

Leishmania (Viannia) braziliensis is an important Leishmania species circulating in several Central and South American countries. Among Leishmania species circulating in Brazil, Argentina and Colombia, L. braziliensis has the highest genomic variability. However, genomic variability at the whole genome level has been only studied in Brazilian and Peruvian isolates; to date, no Colombian isolates have been studied. Considering that in Colombia, L. braziliensis is a species with great clinical and therapeutic relevance, as well as the role of genetic variability in the epidemiology of leishmaniasis, we analyzed and evaluated intraspecific genomic variability of L. braziliensis from Colombian and Bolivian isolates and compared them with Brazilian isolates. Twenty-one genomes were analyzed, six from Colombian patients, one from a Bolivian patient, and 14 Brazilian isolates downloaded from public databases. The results obtained of Phylogenomic analysis showed the existence of four well-supported clades, which evidenced intraspecific variability. The whole-genome analysis revealed structural variations in the somy, mainly in the Brazilian genomes (clade 1 and clade 3), low copy number variations, and a moderate number of single-nucleotide polymorphisms (SNPs) in all genomes analyzed. Interestingly, the genomes belonging to clades 2 and 3 from Colombia and Brazil, respectively, were characterized by low heterozygosity (~90% of SNP loci were homozygous) and regions suggestive of loss of heterozygosity (LOH). Additionally, we observed the drastic whole genome loss of heterozygosity and possible hybridization events in one genome belonging to clade 4. Unique/shared SNPs between and within the four clades were identified, revealing the importance of some of them in biological processes of L. braziliensis. Our analyses demonstrate high genomic variability of L. braziliensis in different regions of South America, mainly in Colombia and suggest that this species exhibits striking genomic diversity and a capacity of genomic hybridization; additionally, this is the first study to report whole-genome sequences of Colombian L. braziliensis isolates.

Development of Lutzomyia evansi immature stages in peridomiciliary environment in a leishmaniasis urban focus in the Colombian Caribbean

In the Caribbean region of Colombia, Lutzomyia evansi is recognized as the vector for Leishmania infantum and Leishmania braziliensis. Identifying breeding sites and surveying abundance of immature phlebotomine sand flies in urban foci of leishmaniasis are useful tool to design new vector control strategies. The objective of this study was to describe the natural breeding sites of Lu. evansi in peridomiciliary vegetation in a peri-urban area of the Colombian Caribbean region. Between 2013 and 2015, 466 microhabitats were sampled, collecting 621 kg of soil samples. The explored microhabitats were bases and tree holes, fallen trees, animal caves, leaf litter, domestic animal shelters, and the inside of dwellings. The immature phlebotomines were recovered by direct search under the stereoscope and incubation of soil samples. In total, 103 microhabitats, associated with 17 arboreal species, were identified as natural breeding sites. Of 422 immature sandflies detected, 98.6% were found in soils at the base of the trees. Eight species of the genus Lutzomyia were identified, of which Lu. evansi (52.6%) was the most abundant, followed by Lu. rangeliana, Lu. cayennensis cayennensis, Lu. atroclavata, Lu. micropyga, Lu. trinidadensis, Lu. dubitans and Lu. gomezi. The arboreal species Cordia alba was the most used by phlebotomines for the development of their immature stages. From 63 natural breeding sites identified 268 immatures were recovered including 176 Lu. evansi. The accumulated precipitation showed correlation (R2 = 0.643, p = 0.013) with the abundance of developmental stages, which increased in September and October. The natural breeding sites of Lu. evansi exhibited a local pattern of occurrence dependent on rainfall. The physicochemical analysis of the soil samples showed that the natural sites for C. alba were categorized as fertile loam soils. This is the first systematic study that estimates the temporal variation of immature sand flies in peridomiciliary vegetation in a peri-urban focus of leishmaniasis in Colombia.

Behavioral Aspects of Phlebotomine Sand Flies Associated with a Case of Cutaneous Leishmaniasis in Atlántico, Northern Colombia

After the first autochthonous case of cutaneous leishmaniasis was reported in the Atlántico department in the Caribbean region of Colombia, entomological sampling was conducted in the specific areas where the infection might have occurred. CDC traps were installed inside and outside dwellings in the peri-urban and rural areas of a settlement in the municipality of Luruaco. Sampling was performed during the night with protected human bait, and phlebotomine sand flies were actively sampled from potential diurnal resting sites within dwellings. Ten species of the genus Lutzomyia were identified; Lutzomyia evansi was the dominant species (78%) in the rural and peri-urban areas as well as in the different sampled habitats, followed by Lutzomyia panamensis and Lutzomyia gomezi. There was a 100% household infestation by Lu. evansi, and its indoor mean abundance was 13.3 sand flies/CDC trap/night. The indoor mean abundance of Lu. panamensis and Lu. gomezi was only 0.9 and 0.8 sand flies/CDC trap/night, respectively. Female Lu. evansi were collected with protected human bait, mostly in the peridomestic area, with sustained activity during the night and a slight increase in the activity from 19:00 to 23:00 hours. Of the total sand flies captured in the diurnal resting sites, 73.1% were collected from the walls of bedrooms and corresponded to Lu. evansi, Lutzomyia cayennensis cayennensis, and Lutzomyia trinidadensis. Owing to their vectorial importance, the species on which entomological surveillance should be focused are Lu. evansi, Lu. panamensis, and Lu. gomezi. The biting and resting behavior reported in this study will help guide vector prevention and the control of leishmaniasis within the study area.

Primera aproximación a la fauna flebotomínea (Psychodidae: Phlebotominae) del departamento de Atlántico

Dentro del género Lutzomyiaalgunas especies son vectores de la enfermedad llamada leishmaniasis, la cual tiene implicaciones en la salud pública, desarrollando diferentes manifestaciones clínicas como leishmaniasis cutánea, visceral y mucocutánea que afectan altamente al ser humano. El objetivo de este estudio fuerealizar un inventario de las especies del género Lutzomyia presentes en seis zonas del departamento del Atlántico. Se implementaron 3 técnicas de capturas tradicionales: trampas CDC entre 18:00-06:00, trampa Shannon entre 19:00-22:00 y búsqueda activa de flebotomíneos con aspiradores bucales en troncos, bases de árboles y otros sitios entre 09:00-11:00 y 16:00-17:30, en seis municipios del departamento del Atlántico, Colombia. Se capturaron diez especies flebotomíneas y se reporta por vez primera para el departamento del Atlántico el hallazgo de Lutzomyia longipalpis y Lutzomyia atroclavata. De las diez especies capturadas, Lutzomyia longipalpistiene antecedentes como vector de Leishmania infantumen Colombia y en otras regiones de Latinoamérica, además es considerada el principal vector de leishmaniasis visceral en las Américas. La especie más abundante y con mayor distribución espacial fue Lu. evansi, principal vector de leishmaniasis visceral en la región Caribe. En conclusión,la riqueza de la fauna flebotomínea del departamento de Atlántico se actualiza a doce especies, con el primer registro de Lu. longipalpisy Lu. atroclavata. También se reporta la fauna flebotomínea por primera vez en localidades del departamento de Atlántico como Campeche, Puerto Colombia, Luruaco, Ponedera y Campo de la Cruz.

Ecological niche modelling for predicting the risk of cutaneous leishmaniasis in the Neotropical moist forest biome

A major challenge of eco-epidemiology is to determine which factors promote the transmission of infectious diseases and to establish risk maps that can be used by public health authorities. The geographic predictions resulting from ecological niche modelling have been widely used for modelling the future dispersion of vectors based on the occurrence records and the potential prevalence of the disease. The establishment of risk maps for disease systems with complex cycles such as cutaneous leishmaniasis (CL) can be very challenging due to the many inference networks between large sets of host and vector species, with considerable heterogeneity in disease patterns in space and time. One novelty in the present study is the use of human CL cases to predict the risk of leishmaniasis occurrence in response to anthropogenic, climatic and environmental factors at two different scales, in the Neotropical moist forest biome (Amazonian basin and surrounding forest ecosystems) and in the surrounding region of French Guiana. With a consistent data set never used before and a conceptual and methodological framework for interpreting data cases, we obtained risk maps with high statistical support. The predominantly identified human CL risk areas are those where the human impact on the environment is significant, associated with less contributory climatic and ecological factors. For both models this study highlights the importance of considering the anthropogenic drivers for disease risk assessment in human, although CL is mainly linked to the sylvatic and peri-urban cycle in Meso and South America.

Surveillance of phlebotomine fauna and Didelphis marsupialis (Didelphimorphia: Didelphidae) infection in an area highly endemic for visceral leishmaniasis in Colombia

INTRODUCTION

The study of the interaction between the parasite, the vector and the mammalian hosts, including man, allows to understand the behavior of the leishmaniases.

OBJECTIVE

To determine the presence of Lutzomyia species and to detect the Leishmania infection in Didelphis marsupialis in an endemic area for visceral leishmaniasis.

MATERIALS AND METHODS

Phlebotomine fauna and individuals of D. marsupialis were collected with CDC and Tomahawk™ traps, respectively. The species of Lutzomyia were identified using the Young and Duncan key (1994). Ear and tail biopsies and blood samples from D. marsupialis were taken to identify the Leishmania species by amplifying a fragment of the gene associated with the 70 kD heat shock protein.

RESULTS

Seven Lutzomyia species were identified: Lu. evansi, Lu. gomezi, Lu. panamensis, Lu. dubitans, Lu. cayennensis cayennensis, Lu. rangeliana and Lu. trinidadensis. The first three species have epidemiological importance in Colombia because of their implications in the transmission of the Leishmania parasite. Sixty-five tissue samples from 19 D. marsupialis individuals were negative for Leishmania spp.

CONCLUSIONS

The presence of the Lutzomyia species that have been identified as vectors for Leishmania inside and around houses in the village of El Bledo, in El Carmen de Bolívar represents a risk of infection. Furthermore, the presence of Lu. panamensis is reported for first time in El Carmen de Bolívar in Colombia. Although the lack of detection of Leishmania spp. in D. marsupialis samples may suggest that D. marsupialis does not play an important role in the transmission cycle of Leishmania in this region, it is necessary to carry out further longitudinal studies to confirm this hypothesis.

Evaluating the spatial distribution of Leishmania parasites in Colombia from clinical samples and human isolates (1999 to 2016)

In Colombia, nine species of parasites of the genus Leishmania circulate in more than 20 sand fly species, putting at risk of contracting the disease approximately 60% of the population. The Federico Lleras Acosta Dermatological Center, a reference center in Colombia, has been treating patients with cutaneous and mucosal leishmaniasis for more than 15 years, identifying the infecting Leishmania species from different clinical samples, and recording systematically all the epidemiological and geographic information related to each diagnosed patient. With this valuable information, the objective of this work was to perform a long term and large-scale study, aiming to identify the Leishmania species circulating in Colombia from clinical samples from 1999 to 2016, and to assess their current and potential spatial distribution. In all, four Leishmania species were identified in 688 samples from 183 municipalities distributed in 28 of the 32 departments of the country, and 387 records were georeferenced, from 20 departments. The most widespread species was L. (V.) braziliensis, showing new collection records, and the species related to areas with highest leishmaniasis transmission was L. (V.) panamensis. Ecological niche models were built for the three species that had more than 20 georeferenced records, showing a potential distribution for L. (V.) braziliensis on 42% of the national territory mainly in the interandean valleys, and the Orinoquia and Amazon regions. Leishmania (V.) guyanensis potential distribution covers 36% of Colombia continental territory with a spatial distribution similar to that of L. (V.) braziliensis. There was a marked tendency of L. (V.) panamensis to be distributed in the northwest of the country occupying 35% of the national area and mainly in areas of transformed ecosystems. Species were identified in patients from areas where the occurrence of cases was unprecedented, which suggests that the distribution of Leishmania may be greater than currently known. To improve the predictive capacity of the models, we suggest incorporating, in future studies, Leishmania samples from vectors and reservoirs that have a greater dependence on environmental variables. Our results are an important tool for health systems because they allow potential areas of transmission and information gaps to be identified.

Environmental and socio-economic determinants associated with the occurrence of cutaneous leishmaniasis in the northeast of Colombia

Background

Cutaneous leishmaniasis (CL) is a vector-borne disease that is widely distributed in most tropical regions. Colombia has experienced an important increase in its incidence during the last decade. There are CL transmission foci in the Colombian departments of Santander and Norte de Santander.

Objectives

To identify environmental and socio-economic variables associated with CL incidence in the municipalities of the northeast of Colombia between 2007 and 2016.

Methods

This was an ecological study of CL cases aggregated by municipality. The cases reported during the study period were analyzed with a negative binomial regression to obtain the adjusted incident rate ratio for environmental and socio-economic variables.

Findings

During the study period, 10 924 cases of CL were reported, and 110 (86.6%) municipalities reported at least one CL case. The coverages of forest (aIRR 1.05, 95% CI 1.03-1.07), heterogeneous agricultural zones (aIRR 1.04, 95% CI 1.02-1.06) and permanent crops (aIRR 1.07, 95% CI 1.02-1.12) were associated with a higher incidence of CL. Conversely, urban functionality (aIRR 0.95, 95% CI 0.92-0.96), minimal-altitude above sea level (aIRR 0.84, 95% CI 0.79-0.90) and shrub coverage (aIRR 0.98, 95% CI 0.95-1.0) were negatively associated with the incidence of CL in the municipality.

Main conclusions

Our results confirm the importance of environmental determinants, such as height above sea level, and coverage of forest, permanent crops and heterogeneous agricultural zones, for the occurrence of CL; these findings also suggest the importance of shrub coverage. Furthermore, urban functionality was a socio-economic determinant independently associated with CL incidence.

Diversity patterns, Leishmania DNA detection, and bloodmeal identification of Phlebotominae sand flies in villages in northern Colombia

Leishmaniases are neglected tropical diseases exhibiting complex transmission cycles due to the number of parasite species circulating, sand fly species acting as vectors and infected mammals, including humans, which are defined in the New World as accidental hosts. However, current transmission scenarios are changing, and the disease is no longer exclusively related to forested areas but urban transmission foci occur, involving some species of domestic animals as suspected reservoirs. The aim of this study was to determine the transmission cycles in urban environments by evaluating sand fly diversity, detection of Leishmania DNA, and bloodmeal sources through intra and peridomestic collections. The study was carried out in Colombia, in 13 municipalities of Cordoba department, implementing a methodology that could be further used for the evaluation of vector-borne diseases in villages or towns. Our sampling design included 24 houses randomly selected in each of 15 villages distributed in 13 municipalities, which were sampled in two seasons in 2015 and 2016. Sand flies were collected using CDC light traps placed in intra and peridomestic habitats. In addition to the morphological identification, molecular identification through DNA barcodes was also performed. A total of 19,743 sand flies were collected and 13,848 of them (10,268 females and 3,580 males) were used in molecular procedures. Circulation of two known parasite species–Leishmania infantum and Leishmania panamensis was confirmed. Blood source analyses showed that sand flies fed on humans, particularly in the case of the known L. infantum vector, P. evansi; further analyses are advised to evaluate the reservoirs involved in parasite transmission. Our sampling design allowed us to evaluate potential transmission cycles on a department scale, by defining suspected vector species, parasite species present in different municipalities and feeding habits.

Environmental risk modelling and potential sand fly vectors of cutaneous leishmaniasis in Chitral district: a leishmanial focal point of mount Tirich Mir, Pakistan

OBJECTIVE

To provide baseline information about suspected vectors and the incidence, distribution and an active zone of transmission for cutaneous leishmaniasis (CL) in Chitral, Pakistan, using GIS tools; and to investigate the role of environmental factors in the disease dynamics.

METHOD

Two surveys in 2014 and 2016 as a basis for choropleth and environmental risk mapping.

RESULTS

A total of 769 captured specimens yielded 14 Phlebotomus and six Sergentomyia species including two potential vectors of CL, i.e. Phlebotomus papatasi and Phlebotomus sergenti. P. papatasi (71%) was dominant, followed by P. sergenti (18%). A choropleth map generated in Arcmap 10.1 based on 1560 CL case reports displayed maximum prevalence (0.92-2.5%) in Ayun, Broz, Charun, Chitral 1 and 2 and Darosh 1 and 2 union councils. An environmental risk map constructed by MaxEnt 3.3.3 defined an active zone of transmission based on leishmaniasis occurrence records (n = 315). The analysis of variable contribution in MaxEnt indicates significance of elevation (54.4%), population density (23.3%) and land use/land cover (6.6%) in CL disease dynamics.

CONCLUSION

The probability of CL increases (0.6-1 on logistic scale) in severely deforested areas, in lowland valleys and in regions with high-population density.

Eco-epidemiological aspects, natural detection and molecular identification of Leishmania spp. in Lutzomyia reburra, Lutzomyia barrettoi majuscula and Lutzomyia trapidoi

Introducción. La provincia de Pichincha, Ecuador, es un área endémica de leishmaniasis cutánea, en donde se han determinado como vectores los flebotomíneos antropofílicos con infección natural por Leishmania spp. Sin embargo, no se ha evaluado el papel en la transmisión de las especies zoofílicas.Objetivo. Evaluar la infección natural por Leishmania en dos especies de flebotomíneos zoofílicos, Lutzomyia reburra y Lu. barrettoi majuscula, y en una antropofílica, Lu. trapidoi, así como la endofagia y la sinantropía de estas especies en el noroccidente de Pichincha.Materiales y métodos. Los flebotomíneos se recolectaron en trampas de luz CDC colocadas en diferentes hábitats y altitudes en sitios que son focos de leishmaniasis cutánea. La infección con Leishmania spp. se detectó en el ADN genómico de hembras de las especies de flebotomíneos de interés. Se amplificó el gen espaciador interno de la transcripción del ARN ribosómico, unidad I (ITS1), y los genes de las topoiso-merasas mitocondrial II (mtTOPOII) y nuclear II (TopoII). Se determinaron los porcentajes de positividad para Leishmania a escala espaciotemporal, la proporción de endofagia y el índice de sinantropía.Resultados. Se determinó la presencia de infección natural por Le. amazonensis en Lu. reburra (9,5 %) y Lu. b. majuscula (23,8 %); en Lu. trapidoi se detectaron Le. amazonensis, Le. brazilienis y Le. naiffi-lainsoni. Los flebotomíneos eran asinantrópicos y con baja endofagia.Conclusión. Se registró por primera vez la presencia de infección natural en Lu. reburra y Lu. barrettoi majuscula por Le. amazonensis, y se demostró la importancia de los flebotomíneos zoofílicos en el mantenimiento del ciclo de transmisión de Leishmania spp. en focos endémicos.

First description of Leishmania (Viannia) infection in Evandromyia saulensis, Pressatia sp. and Trichophoromyia auraensis (Psychodidae: Phlebotominae) in a transmission area of cutaneous leishmaniasis in Acre state, Amazon Basin, Brazil

Studies on the sandfly fauna to evaluate natural infection indexes are still limited in the Brazilian Amazon, a region with an increasing incidence of cutaneous leishmaniasis. Here, by using a multiplex polymerase chain reaction directed to Leishmania kDNA and hybridisation, we were able to identify L. (Viannia) subgenus in 12 out of 173 sandflies captured in the municipality of Rio Branco, Acre state, revealing a positivity of 6.94%. By sequencing the Leishmania 234 bp-hsp70 amplified products from positive samples, infection by L. (V.) braziliensis was confirmed in five sandflies: one Evandromyia saulensis, three Trichophoromyia auraensis and one Pressatia sp. The finding of L. (Viannia) DNA in two Ev. saulensis corresponds to the first record of possible infection associated with this sandfly. Moreover, our study reveals for the first time in Brazil, Th. auraensis and Pressatia sp. infected by L. (Viannia) parasites.

Evidence for anthropophily in five species of phlebotomine sand flies (Diptera: Psychodidae) from northern Colombia, revealed by molecular identification of bloodmeals

Identification of the bloodmeal sources of phlebotomine sand flies is fundamental to determining which species are anthropophilic and understanding the transmission of Leishmania parasites in natural epidemiological settings. The objective of this study was to identify sand fly bloodmeals in the mixed leishmaniasis focus of the department of Sucre, northern Colombia. In all 141 engorged female sand flies were analyzed, after being captured in intradomiciliary, peridomiciliary and extradomiciliary habitats with Shannon and CDC traps and by active searching in diurnal resting sites. Bloodmeals were identified by sequencing and analysis of a 358bp fragment of the mitochondrial gene Cytochrome b (CYB) and a 330bp fragment of the nuclear gene prepronociceptin (PNOC). Using both genes 105 vertebrate bloodmeals were identified, with an efficiency of 72% for CYB but only 7% for PNOC. Ten species of vertebrates were identified as providing bloodmeal sources for 8 sand fly species: Homo sapiens (Lutzomyia evansi, Lutzomyia panamensis, Lutzomyia micropyga, Lutzomyia shannoni and Lutzomyia atroclavata), Equus caballus (L. evansi, L. panamensis and Lutzomyia cayennensis cayennensis), Equus asinus (L. evansi and L. panamensis), Bos taurus (L. evansi, L. panamensis and L. c. cayennensis), Tamandua mexicana (L. shannoni and Lutzomyia trinidadensis), Proechimys guyanensis (L. evansi, L. panamensis and L. c. cayennensis), Mabuya sp. (Lutzomyia micropyga), Anolissp. (L. micropyga), Sus scrofa (L. evansi and Lutzomyia gomezi) and Gallus gallus (L. evansi). Cattle, donkeys, humans and pigs were significantly more important than other animals (P=0.0001) as hosts of L. evansi, this being the most abundant sand fly species. The five Lutzomyia species in which blood samples of human origin were detected included L. micropyga and L. atroclavata, constituting the first evidence of anthropophily in both species.

Spatial Distribution of Sand Fly Vectors and Eco-Epidemiology of Cutaneous Leishmaniasis Transmission in Colombia

Background

Leishmania is transmitted by Phlebotominae insects that maintain the enzootic cycle by circulating between sylvatic and domestic mammals; humans enter the cycles as accidental hosts due to the vector’s search for blood source. In Colombia, leishmaniasis is an endemic disease and 95% of all cases are cutaneous (CL), these cases have been reported in several regions of the country where the intervention of sylvatic areas by the introduction of agriculture seem to have an impact on the rearrangement of new transmission cycles. Our study aimed to update vector species distribution in the country and to analyze the relationship between vectors’ distribution, climate, land use and CL prevalence.

Methods

A database with geographic information was assembled, and ecological niche modeling was performed to explore the potential distribution of each of the 21 species of medical importance in Colombia, using thirteen bioclimatic variables, three topographic and three principal components derived from NDVI. Binary models for each species were obtained and related to both land use coverage, and a CL prevalence map with available epidemiological data. Finally, maps of species potential distribution were summed to define potential species richness in the country.

Results

In total, 673 single records were obtained with Lutzomyia gomezi, Lutzomyia longipalpis, Psychodopygus panamensis, Psathyromyia shannoni and Pintomyia evansi the species with the highest number of records. Eighteen species had significant models, considering the area under the curve and the jackknife results: L. gomezi and P. panamensis had the widest potential distribution. All sand fly species except for Nyssomyia antunesi are mainly distributed in regions with rates of prevalence between 0.33 to 101.35 cases per 100,000 inhabitants and 76% of collection data points fall into transformed ecosystems.

Discussion

Distribution ranges of sand flies with medical importance in Colombia correspond predominantly to disturbed areas, where the original land coverage is missing therefore increasing the domiciliation potential. We highlight the importance of the use of distribution maps as a tool for the development of strategies for prevention and control of diseases.

Leishmaniasis in travelers: a literature review

Leishmaniasis is a vector-borne protozoan infection whose clinical spectrum ranges from asymptomatic infection to fatal visceral leishmaniasis. Over the last decades, an increase in imported leishmaniasis cases in developed, non-endemic countries, have been pointed-out from a review of the international literature. Among the possible causes are increasing international tourism, influx of immigrants from endemic regions and military operations. The main area for the acquisition of cutaneous leishmaniasis, especially for adventure travelers on long-term trips in highly-endemic forested areas, is represented from South America, whereas popular Mediterranean destinations are emerging as the main areas to acquire visceral variant. Leishmaniasis should be considered in the diagnostic assessment of patients presenting with a compatible clinical syndrome and a history of travel to an endemic area, even if this occurred several months or years before. Adventure travelers, researchers, military personnel, and other groups of travelers likely to be exposed to sand flies in endemic areas, should receive counseling regarding leishmaniasis and appropriate protective measures.

Sand fly fauna (Diptera: Psychodidae: Phlebotominae) in an area of leishmaniasis transmission in the municipality of Rio Branco, state of Acre, Brazil

BACKGROUND

Notifications concerning American Cutaneous Leishmaniasis have increased in recent years in the state of Acre, Brazil. Despite identification of distinct Leishmania species isolated from cutaneous lesions, there are still no records of visceral leishmaniasis in the state. However, studies on the sand fly fauna in this region are still limited.

FINDINGS

Insects were collected from April 2011 to April 2012, using HP light traps distributed in four residential areas and one recreational area in Rio Branco, Capital of the State of Acre in the Amazon region of Brazil. A total of 456 sand flies were collected, comprising 256 females and 200 males. Taxonomic identification revealed 16 Phlebotominae genera and 23 species, as follows: Trichophoromyia auraensis, Nyssomyia whitmani, Nyssomyia antunesi, Pressatia choti, Evandromyia saulensis, Evandromyia walkeri, Evandromyia begonae, Migonemyia migonei, Pintomyia serrana, Psychodopygus paraensis, Sciopemyia sordelii, Migonemyia pusilla, Pintomyia nevesi, Brumptomyia avellari, Micropygomyia acanthopharynx, Micropygomyia micropyga, Pintomyia odax, Lutzomyia sherlocki, Pressatia calcarata, Pressatia duncanae, Bichromomyia flaviscutellata, Evandromyia bourrouli and Evandromyia bacula. From this group, Tr. auraensis and Ny. whitmani were the most abundant species in both forested areas and the peridomiciliary environment.

CONCLUSIONS

We find that the sand fly fauna in the urban and peri urban areas of Rio Branco is very diverse comprising 23 species, as diverse as that in areas of primary forest. Some species, such as Nyssomyia whitmani, Ny. antunesi and Bichromomyia flaviscutellata are known vectors of parasites responsible for cutaneous leishmaniasis, and Trichophoromyia auraensis is a putative vector in this Amazonian region.

Phylogeography of the Lutzomyia gomezi (Diptera: Phlebotominae) on the Panama Isthmus

BACKGROUND

Lutzomyia gomezi (Nitzulescu, 1931) is one of the main Leishmania (Vianna) panamensis vectors in Panama, and despite its medical significance, there are no population genetic studies regarding this species. In this study, we used the sequences of the mitochondrial gene cytochrome b/start of NADH1 and the nuclear elongation gene α-1 in order to analyze genetic variation and phylogeographic structure of the Lu. gomezi populations.

METHODS

A total of 86 Lu. gomezi individuals were captured in 38 locations where cutaneous leishmaniasis occurred. DNA was extracted with phenol/chloroform methods and amplification of genes was performed using PCR primers for mitochondrial and nuclear markers.

RESULTS

We found a total of 37 and 26 haplotypes of mitochondrial and nuclear genes, high haplotype diversity (h) for all three populations were detected with both molecular markers. Nucleotide diversity (π) was estimated to be high for all three populations with the mitochondrial marker, which was opposite to the estimate with the nuclear marker. In the AMOVA Φst recorded moderate (mitochondrial) and small (nuclear) population structure with statistical significance among populations. The analysis of the fixation index (Fst) used to measure the differentiation of populations showed that with the exception of the population located in the region of Bocas del Toro, the other populations presented with minor genetic differentiation. The median-Joining network of the mitochondrial marker reveled three clusters and recorded four haplotypes exclusively of localities sampled from Western Panama, demonstrating strong divergence. We found demographic population expansion with Fu´s Fs neutrality test. In the analysis mismatch distribution was observed as a bimodal curve.

CONCLUSION

Lu. gomezi is a species with higher genetic pool or variability and mild population structure, due to possible capacity migration and local adaptation to environmental changes or colonization potential. Thus, knowledge of the genetic population and evolutionary history is useful to understand the implications of different population genetic structures for cutaneous leishmaniasis epidemiology.

Climatic factors and population density of Lutzomyia longipalpis (Lutz & Neiva, 1912) in an urban endemic area of visceral leishmaniasis in midwest Brazil

The life cycle of vectors and the reservoirs that participate in the chain of infectious diseases have a strong relationship with the environmental dynamics of the ecosystems in which they live. Oscillations in population abundance and seasonality of insects can be explained by factors inherent in each region and time period. Therefore, knowledge of the relationship and influence of environmental factors on the population of Lutzomyia longipalpis is necessary because of the high incidence of visceral leishmaniasis (VL) in Brazil. This study evaluates the influence of abiotic variables on the population density and seasonal behavior of L. longipalpis in an urban endemic area of VL in Brazil. The sand fly captures were performed every two months between November, 2009 and November, 2010 in the peridomicile of 13 randomly selected residences. We captured 1,367 specimens of L. longipalpis, and the ratio of male/female flies was 2.86:1. The comparison of the total male specimens in the two seasons showed a statistical difference in the wet season, but there was no significant difference when considering the total females. With respect to climatic variables, a significant negative association was observed only with wind speed. During periods of high wind speeds, the population density of this vector decreased. The presence of L. longipalpis was found in all months of the study with bimodal behavior and population peaks during the wet season.

Current and future niche of North and Central American sand flies (Diptera: psychodidae) in climate change scenarios

Ecological niche models are useful tools to infer potential spatial and temporal distributions in vector species and to measure epidemiological risk for infectious diseases such as the Leishmaniases. The ecological niche of 28 North and Central American sand fly species, including those with epidemiological relevance, can be used to analyze the vector's ecology and its association with transmission risk, and plan integrated regional vector surveillance and control programs. In this study, we model the environmental requirements of the principal North and Central American phlebotomine species and analyze three niche characteristics over future climate change scenarios: i) potential change in niche breadth, ii) direction and magnitude of niche centroid shifts, iii) shifts in elevation range. Niche identity between confirmed or incriminated Leishmania vector sand flies in Mexico, and human cases were analyzed. Niche models were constructed using sand fly occurrence datapoints from Canada, USA, Mexico, Guatemala and Belize. Nine non-correlated bioclimatic and four topographic data layers were used as niche components using GARP in OpenModeller. Both B2 and A2 climate change scenarios were used with two general circulation models for each scenario (CSIRO and HadCM3), for 2020, 2050 and 2080. There was an increase in niche breadth to 2080 in both scenarios for all species with the exception of Lutzomyia vexator. The principal direction of niche centroid displacement was to the northwest (64%), while the elevation range decreased greatest for tropical, and least for broad-range species. Lutzomyia cruciata is the only epidemiologically important species with high niche identity with that of Leishmania spp. in Mexico. Continued landscape modification in future climate change will provide an increased opportunity for the geographic expansion of NCA sand flys' ENM and human exposure to vectors of Leishmaniases.

Phlebotomine sandflies and the spreading of leishmaniases and other diseases of public health concern

Phlebotomine sandflies transmit pathogens that affect humans and animals worldwide. We review the roles of phlebotomines in the spreading of leishmaniases, sandfly fever, summer meningitis, vesicular stomatitis, Chandipura virus encephalitis and Carrión's disease. Among over 800 species of sandfly recorded, 98 are proven or suspected vectors of human leishmaniases; these include 42 Phlebotomus species in the Old World and 56 Lutzomyia species in the New World (all: Diptera: Psychodidae). Based on incrimination criteria, we provide an updated list of proven or suspected vector species by endemic country where data are available. Increases in sandfly diffusion and density resulting from increases in breeding sites and blood sources, and the interruption of vector control activities contribute to the spreading of leishmaniasis in the settings of human migration, deforestation, urbanization and conflict. In addition, climatic changes can be expected to affect the density and dispersion of sandflies. Phlebovirus infections and diseases are present in large areas of the Old World, especially in the Mediterranean subregion, in which virus diversity has proven to be higher than initially suspected. Vesiculovirus diseases are important to livestock and humans in the southeastern U.S.A. and Latin America, and represent emerging human threats in parts of India. Carrión's disease, formerly restricted to regions of elevated altitude in Peru, Ecuador and Colombia, has shown recent expansion to non-endemic areas of the Amazon basin.

Genetic structure and divergence in populations of Lutzomyia cruciata, a phlebotomine sand fly (Diptera: Psychodidae) vector of Leishmania mexicana in southeastern Mexico

The low dispersal capacity of sand flies could lead to population isolation due to geographic barriers, climate variation, or to population fragmentation associated with specific local habitats due to landscape modification. The phlebotomine sand fly Lutzomyia cruciata has a wide distribution throughout Mexico and is a vector of Leishmania mexicana in the southeast. The aim of this study was to evaluate the genetic diversity, structure, and divergence within and among populations of Lu. cruciata in the state of Chiapas, and to infer the intra-specific phylogeny using the 3' end of the mitochondrial cytochrome b gene. We analyzed 62 sequences from four Lu. cruciata populations and found 26 haplotypes, high genetic differentiation and restricted gene flow among populations (Fst=0.416, Nm=0.701, p<0.001). The highest diversity values were recorded in populations from Loma Bonita and Guadalupe Miramar. Three lineages (100% bootstrap and 7% overall divergence) were identified using a maximum likelihood phylogenetic analysis which showed high genetic divergence (17.2-22.7%). A minimum spanning haplotype network also supported separation into three lineages. Genetic structure and divergence within and among Lu. cruciata populations are hence affected by geographic heterogeneity and evolutionary background. Data obtained in the present study suggest that Lu. cruciata in the state of Chiapas consists of at least three lineages. Such findings may have implications for vector capacity and hence for vector control strategies.

[Molecular analysis of natural infection of Lutzomyia longipalpis in an endemic area for visceral leishmaniasis in Brazil]

The main purpose of this study was to investigate natural infection by Leishmania chagasi in female sand flies in a visceral leishmaniasis (VL) focus on São Luís Island, Maranhão State, Brazil. Molecular analysis by polymerase chain reaction (PCR) was applied to determine the rate of natural infection of Lutzomyia longipalpis by L. chagasi in areas of old and recent human settlement on São Luís Island. Based on a sample of 800 female specimens captured from March to August 2005, the natural infection rate was 1.25% in an area of old settlement and 0.25% in two recently settled areas. Infection of L. longipalpis was detected in both areas, regardless of the number of reported human VL cases, indicating that other factors modulating infection in the wild need to be investigated. The results confirm PCR as a specific technique and an important tool for epidemiological surveillance.

Diversity of phlebotomine sand flies (Diptera: Psychodidae) in Ibitipoca State Park, Minas Gerais, Brazil

Leishmaniasis is a complex of zoonotic diseases that are endemic to many Brazilian states. They are transmitted to the vertebrates by the bite of the hematophagous female sand fly (Diptera: Psychodidae) vectors. Despite the increasing occurrence of visceral and cutaneous leishmaniasis cases in large urban centers, their transmission continues to occur primarily in a wild environment and may be associated with professional activities, ecotourism activities, or both. This study investigates the ecological parameters of the sand flies present in Ibitipoca State Park, Minas Gerais, Brazil. During 2009, systematic collections of sand flies were made monthly using HP light traps installed at five sites, including three natural settings (a cave, riparian vegetation, and a rain forest), the tourist and researchers' accommodations, and a surrounding domestic livestock area. In total, 161 sand flies (seven species) were collected, the most abundant, particularly in the surrounding domestic livestock area, being Lutzomyia (Psychodopygus) lloydi (Antunes, 1937). Furthermore, a previously unidentified Lutzomyia (Sciopemyia) sp. was prevalent in the cave environment. There are no existing records of the occurrence of leishmaniasis in Ibitipoca State Park; however, the some species of the subgenus Psychodopygus are known vectors of Leishmania spp in Brazil. Hence, the presence of a species of this genus in areas surrounding the park may represent a risk to ecotourism and the local inhabitants. Our study shows the importance of regular monitoring of the various areas used by humans to determine the distribution and spread of sand fly vectors for preventive management to forestall potential risk to health and consequent effect on ecotourists.

Autochthonous visceral leishmaniasis in Brasília, Federal District, Brazil

INTRODUCTION: Visceral leishmaniasis is a public health threat in Brazil considering the high lethality rates and increasing geographical dispersion to large urban conglomerates over the past 25 years. This study aimed to confirm suspected autochthonous cases of visceral leishmaniasis reported from 2005 to 2009 among individuals living in Brasilia, Federal District. METHODS: A retrospective review of the surveillance data obtained on a regular basis and clinical records of the reported cases were performed in 2009. RESULTS: Data from entomological and canine surveys revealed the presence of both Lutzomyia longipalpis and positive serology for Leishmania in dogs within 19 of the 21 neighborhoods where human cases occurred since 2005. The review of surveillance data and medical records, together with the entomological and canine survey data, permitted confirmation of 21 autochthonous human cases in the Federal District. The disease predominantly affected children (12/21) and those from the Sobradinho region (16/21); the typical presentation of fever, hepatosplenomegaly and pancytopenia was observed in 67% of cases. Three deaths occurred during the study period. Leishmania (Leishmania) chagasi was successfully isolated from one human case and twelve canine cases. CONCLUSIONS: Visceral leishmaniasis should be considered endemic in Brasilia based on the documented epidemiological behavior herein described and the confirmed autochthony of human cases.

Nuevos registros de flebotomíneos (Diptera: Psychodidae), con el hallazgode Lutzomyia longipalpis (Lutz & Neiva, 1912), en los alrededoresde la Ciudad de Sincelejo, Colombia

Se registra por primera vez, para la Costa Caribe de Colombia, la presencia de Lutzomyia longipalpis (Lutz & Neiva, 1912), L. shannoni (Dyar, 1929), L. micropyga (Mangabeira, 1942) y L. atroclavata (Knab, 1913), en los alrededores de un núcleo urbano. Los flebotomíneos se recolectaron mediante búsqueda activa con trampas de succión y aspiradores bucales en árboles, en las proximidades de la ciudad de Sincelejo, capital del departamento de Sucre. Se enfatiza en las posibles implicaciones que se pueden derivar del hallazgo de L. longipalpis, debido a la capacidad vectorial de este flebotomíneo, vector natural de Leishmania infantum Nicolle, 1908, en América.

Detection of Leishmania DNA in phlebotomines captured in Campo Grande, Mato Grosso do Sul, Brazil

Over the past years, leishmaniases have become a public health issue in the Brazilian state of Mato Grosso do Sul, particularly in Campo Grande, the state capital. The purpose of this study was to detect the presence of Leishmania DNA in the population of phlebotomine sandflies using DNA amplification by PCR. Insect captures were carried out from 4 pm. to 7 am for 4 consecutive days each month from October 2005 to September 2006 in 16 neighborhoods located in 7 urban regions of Campo Grande. Traps were placed indoors and in the vicinity of households. As many as 971 males and 203 females were collected. One hundred and five naturally fed females were identified and grouped as 1- to 4-specimen pools. DNA extraction was carried out using whole insects. Lutzomyia longipalpis predominated, accounting for 99.15% of the phlebotomines captured. Also found was Nyssomyia whitmani, the vector of tegumentary leishmaniasis. Abundance was greatest in the vicinity of households (69.8% of the phlebotomines captured). As revealed by PCR, parasites were present in 1.9% of the Leishmania spp. specimens investigated and confirmed for visceral leishmaniasis.

Comportamento de Lutzomyia longipalpis, vetor principal da leishmaniose visceral americana, em Campo Grande, Estado do Mato Grosso do Sul

O município de Campo Grande, Estado de Mato Grosso do Sul, Brasil, apresenta ocorrência de casos humanos e caninos de leishmaniose visceral desde 2002 e é classificado como área com transmissão intensa. O estudo foi realizado no período de maio de 2003 a abril de 2005, em parceria com a Fundação Nacional de Saúde e a Secretaria de Saúde do Estado, com o objetivo de conhecer o comportamento e a sazonalidade da espécie Lutzomyia longipalpis. As capturas foram realizadas com armadilhas luminosas, tipo CDC, em doze estações distribuídas na zona urbana. As estações com maior densidade situam-se na parte sul da cidade e a abundância relativa aumentou durante, ou logo após, as precipitações pluviométricas. Nos meses frios e secos a quantidade foi reduzida e a abundância relativa foi maior no peridomicílio. A borrifação com alphacypermetrina, em intervalos de quatro meses, contribuiu para a diminuição do vetor em três das quatro estações borrifadas e, das oito que não sofreram intervenção química, cinco tiveram aumento.

Tegumentary leishmaniasis outbreak in Bella Vista City, Corrientes, Argentina during 2003

Bella Vista City, Corrientes, Argentina, reported an epidemic outbreak of tegumentary leishmaniasis during 2003. The mean age of the 31 cases was 25.0 +/- 13.7 years old, with a sex ratio male:female 1.8, and without mucosal involvement. They clustered in two contiguous neighbourhoods, 96% in the periurban border and 4% in the peripheral outskirts. The transmission peak was estimated to have occurred during April 2003. Four species (3608 sand flies) were captured in nine sites: Lutzomyia neivai (90.1%), Lu. pessoai (8.9%), Lu. migonei (0.8 %), and Brumptomyia avellari (0.2 %). The outskirts/rural capture ratio of Lu. neivai was up to 3, and the outskirts/periurban up to 200. Therefore, the 'urban' transmission in this southernmost known focus is still an ecotone-border associated risk. The changes in human distribution or activities, patches of the secondary vegetation, periurban streams, rainfall of the previous year, and river period floods could all contribute to 'urban' outbreaks in the region. Tegumentary leishmaniasis risk should be assessed for any project that involves changes in land use throughout an endemic area.

New world cutaneous leishmaniasis in travellers

As travel to Latin America has become increasingly common, cutaneous leishmaniasis is increasingly seen among returning travellers--eg, the number of observed cases has doubled in the Netherlands and tripled in the UK in the past decade. A surprisingly high proportion of cases were acquired in rural or jungle areas of the Amazon basin in Bolivia. The clinical manifestations range from ulcerative skin lesions (cutaneous leishmaniasis) to a destructive mucosal inflammation (mucocutaneous leishmaniasis), the latter usually being a complication of infection with Leishmania (Viannia) braziliensis. PCR is now the diagnostic method of choice, since it has a high sensitivity and gives a species-specific diagnosis, allowing species-specific treatment. Treatment of cutaneous leishmaniasis aims to prevent mucosal invasion, to accelerate the healing of the skin lesion(s), and to avoid disfiguring scars. Pentavalent antimonials drugs are still the drug of choice for many patients. However, a high rate of adverse events, length of treatment, and relapses in up to 25% of cases highlight the limitations of these drugs. Although only used in a small number of patients thus far, liposomal amphotericin B shows promising results. Further studies are needed to find efficacious and better-tolerated drugs for new world leishmaniasis.

Importance of Lutzomyia longipalpis in the dynamics of transmission of canine visceral leishmaniasis in the endemic area of Porteirinha Municipality, Minas Gerais, Brazil

A study of Lutzomyia longipalpis (Lutz and Neiva, 1912) (Diptera: Psychodidae), the primary vector of American visceral leishmaniasis (AVL), and the canine form of the disease, was carried out in Porteirinha. The city is situated in the northern part of the Brazilian State of Minas Gerais and is an endemic area of AVL. Systematic phlebotomine captures were performed in seven districts with previously reported cases of canine visceral leishmaniasis, during 2 years (January 2000--December 2001). A total of 2328 specimens of L. longipalpis were captured. The association between the local climate variables and the population density of L. longipalpis was evaluated and rainfall was determined to be a major factor, with increased populations during the rainy season (October--March). At the same time period, blood samples from every dog domiciled in the same seven districts, in total 14,077 animals, were analyzed for infection by viscerotropic Leishmania using indirect immunofluorescence assay (IFA). Accumulated incidence rates of canine VL per district varied from 3.40 to 14.34 for the 2-year period. A positive correlation between the population density of L. longipalpis and the canine cases of visceral leishmaniasis in Porteirinha was observed.

Leishmaniose visceral: estudo de flebotomíneos e infecção canina em Montes Claros, Minas Gerais

A leishmaniose visceral no Brasil estava inicialmente associada a áreas rurais, mas devido às diversas alterações no ambiente como, desmatamentos, urbanização e intenso processo migratório, ocorreu a expansão das áreas endêmicas, levando à urbanização da doença, principalmente nas regiões Sudeste e Centro Oeste do país. No município de Montes Claros, situado ao norte de Minas Gerais, foi feito um estudo para verificação da situação da LV. No ano de 2002 foi realizado inquérito sorológico canino e no período de setembro de 2002 a agosto de 2003 foi feito levantamento entomológico, utilizando armadilhas luminosas de CDC. A prevalência da LV canina apresentou taxa média de infecção em torno de 5%. A fauna de flebotomíneos estimada foi de 16 espécies, totalizando 1043 exemplares. Lutzomyia longipalpis foi a espécie predominante com 74%, o que sugere a sua participação na transmissão de LV em Montes Claros.

Phlebotomine sand flies in Porteirinha, an area of American visceral leishmaniasis transmission in the State of Minas Gerais, Brazil

A study of the phlebotomine sand fly fauna was carried out in an endemic area of American visceral leishmaniasis (AVL) in the municipality of Porteirinha, in the Brazilian state of Minas Gerais. Captures were performed with CDC light traps in 7 districts, 5 days per month, during 2 consecutive years (January 2000 to December 2001). A total of 3240 sand flies were captured and identified. Sixteen species were found, among which 15 belonged to the genus Lutzomyia and one to the genus Brumptomyia. Lutzomyia longipalpis, a proven vector of AVL, was the predominant species (71.85%) throughout the time period. The interference of climatic factors (temperature, humidity, and rainfall) over the populational dynamics of the sand flies was determined. Statistical analysis of the data showed a significant correlation among the number of phlebotomine sand flies collected, rainfall, and humidity, whereas the effect of temperature was negligible, in that particular region. The amount of collected phlebotomine, the number of human cases, and the prevalence of canine AVL in the districts of Porteirinha are discussed.