Diversity of sand flies and Leishmania parasites in an active cutaneous leishmaniasis transmission site in rural Guatemala, 2022

Abstract

Background Cutaneous leishmaniasis (CL) is a parasitic vector borne disease endemic in 90 countries, including Guatemala. Despite the endemicity of the disease in the country, the most important factors that contribute to its transmission remain unknown. To address these knowledge gaps, we characterized the sand fly populations and Leishmania parasites circulating in patients and sand flies in an endemic community in Guatemala. Methods From March to August 2022, we visited the households of 23 patients recently diagnosed with CL to collect sand flies in three environments: indoors, outdoors in animal sheds and in the surrounding forest. The sand fly species were identified using end-point PCR targeting the cytochrome C gene followed by sequencing, and screened for Leishmania DNA by heat-shock protein 70 gene PCR and sequencing. Using the same methodology on lesion tissue smear material from patients, we identified the species of parasites causing infections in the community. Results We collected 93 sand flies (79% females) of at least five species, three of which have been previously associated with Leishmania transmission: Nyssomyia ylephiletor, Bichromomyia olmeca and Lutzomyia cruciata. The highly anthropophilic Ny. ylpehiletor, of which only females were captured, was the most common species (28%) and was primarily collected indoors (73.1%). Four female sand flies were positive for Leishmania DNA, and one of them (Ny. ylephiletor) was captured indoors. The parasite complex L. guyanensis (L. guyanensis and L. panamensis) was found in both sand flies and patients’ samples. In patients we also detected L. braziliensis and a cutaneous form of L. infantum. Three engorged Ny. ylephiletor were screened for blood meal identification, finding humans and domestic pig’s blood. Conclusions This is the first report in Guatemala of the presence of L. guyanensis in patients, and the first characterization of Leishmania infections in humans and sand flies that concur in time and geographical area. The capture of anthropophilic sand flies indoors, some with Leishmania DNA, could suggest indoor transmission of CL, but further studies are needed to confirm our results. These findings are key to local health authorities for decision-making on the appropriate prevention measures, such as the use of insecticide treated bed nets.