Spatial distribution of immatures and adults of Lutzomyia spp. in a periurban focus of leishmaniasis in the Caribbean region of Colombia

CADENA, HORACIO; ESTRADA, LUIS GREGORIO; VELEZ-MIRA, ANDRES; ORTEGA, EDGAR; ACOSTA, LUZ ADRIANA; VIVERO, RAFAEL JOSÉ; URIBE-SOTO, SANDRA; BEJARANO, EDUAR ELÍAS

San Cristobal - Galápagos

Simposio; 10th International Symposium on Phlebotomine Sandflies ISOPS; 2019

Institute of Microbiology of the San Francisco de Quito University and Galapagos Academic Institute for the Arts and the Sciences (GAIAS)

Phlebotomine sand flies are responsible for the transmission of diseases of medical importance, such as bartonellosis, some arboviruses and leishmaniasis. The distribution and abundance of vectors as well as the reporting of new cases of leishmaniasis are affected in combination by climatic factors and some human activities such as deforestation, road construction and unplanned urbanization. The replacement of natural vegetation by agricultural crops has also been proposed as modulators of the distribution and composition of the vectors and a risk factor for leishmaniasis. In Colombia, in the last two decades several studies have described the risk of infection by Leishmania associated with deforestation and the replacement of native vegetation by coffee, cocoa and fruit tree crops. The objective of this study was to describe the spatial distribution of adults and the immature forms of sand flies in the periurban vegetation of an endemic area for leishmaniasis. The study was carried out in three zones of the periurban area of the municipality of Ovejas, department of Sucre, located in a tropical dry forest life zone. The capture of adults at rest, the search for immatures and characterization of the vegetation was carried out at a maximum distance of 200 meters from the dwellings every two months during 2013-2014. Adults at rest were collected on trees with a trunk circumference greater than 30 cm for three consecutive days. The search for immatures was conducted on the base of trees, litter and pens of domestic animals. Plots of 100 m2 each were designed for the floristic characterization of the vegetation in the three study zones. The spatial representation of the sand flies, immature forms and vegetation were constructed with the program QGis version 3.4.4-Madeira.The Shannon-Wiener and Jaccard indexes were used to determine the diversity and similarity of thevegetation. A total of nine field trips were made and 717 phlebotominees were collected at rest in 13 arboreal species. Of the 10 species of sand flies that were collected at rest, Lu. evansi and Lu. cayennensis were the dominant species with 58 and 46% respectively. Cordia alba, Guazuma ulmifolia and Ceiba petandra congregated 86.7% of the sand flies collected at rest. 230 immature forms were recovered from 14 tree species. 66% (n = 152) of the immature were isolated from Cordia alba of which Lu. evansi accounted for 40% (n = 93). The plant community of the three zones was heterogeneous. 95% of the vegetation identified as breeding and resting sites of the phlebotomine was located 100 meters from the houses. The highest frequency and relative dominance of species corresponded to Cordia alba in zones 1 and 3. In this context, the chance of the population coming into contact with sand flies may be greater due to the proximity of the vegetation. The high density of Cordia alba and in turn breeding site of Lu. evansi, recognized vector of visceral and cutaneous leishmaniasis, could favor the intra and peridomiciliar transmission of leishmaniasis. These results suggest considering the role of Cordia alba and its proximity to housing as an ecological marker of risk in this peri-urban focus and include peridomiciliar vegetation in the disease control program.