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

Abstract

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.MethodsA 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.ResultsIn 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.DiscussionDistribution 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.

Climate change is likely to affect the distribution but not parapatry of the Brazilian marmoset monkeys (Callithrix spp.)

“…There are two studies focused on predicting likely future impacts of climate change on Neotropical primates, with results predicting future range contraction (Gouveia et al, ; Meyer, Pie, & Passos, ). This range contraction has also been predicted for other taxa in several biomes in the region, such as trees (e.g., Siqueira & Peterson, ), other vertebrates (Loyola, Lemes, Faleiro, Trindade‐Filho, & Machado, ; Marini, Barbet‐Massin, Lopes, & Jiguet, ; Souza, Lorini, Alves, Cordeiro, & Vale, ; Vale, Lorini, & Cerqueira, ) and invertebrates (Ferro et al, ; Giannini et al, ). If this trend of species’ distribution contraction also holds for the genus Callithrix , depending on its location, it may lead to either (a) a reduction in the overlap between distributions, changing the genus's pattern of distribution from parapatric to allopatric; or (b) a convergence of species’ distributions to some more climatically stable areas, moving the genus's distribution to a sympatric pattern in future.…”

Evaluation of a Multilocus Sequence Typing (MLST) scheme for Leishmania (Viannia) braziliensis and Leishmania (Viannia) panamensis in Colombia

“…When these dispersions are compared with the geographical distribution of Leishmania vectors in Colombia reported by Ferro et al [36], we observed that L. braziliensis DSTs 6 and 7 are restricted to the department of Norte de Santander overlapping with the distribution of Pintomyia spinicrassa in that department; and no other DSTs were found in the other departments (Cundinamarca and Boyacá) [36]. Likewise, a slight overlap of L. panamensis DST 3 was observed with the vector P. ovallesi in the department of Cundinamarca [36], indicating that this sandfly species might be a potential vector of L. panamensis [37]. This suggests a possible selection by the vector of some genetic variants.…”

Species of sand flies (Diptera: Psychodidae) collected from natural reserves in the Pacific and Darien regions of Colombia

“…trapidoi puede pasar de ser un vector secundario a ser vector primario en ausencia de Lu. panamensis, lo cual es de importancia en salud pública porque la superposición de especies de vectores y la alternancia estacional implican una mayor complejidad en los ciclos de transmisión de la leishmaniasis (35 En conclusión, el análisis integrador de los caracteres morfológicos y moleculares es indispensable para un registro más preciso de los inventarios de flebotomíneos (37), ya que las hembras de algunas especies carecen de caracteres morfológicos distintivos (38). Asimismo, es necesario llevar a cabo curadurías sistemáticas de las secuencias registradas en GenBank, sobre todo cuando provienen de áreas geográficas cuya diversidad es poco conocida.…”