Seasonal variation and natural infection of Lutzomyia antunesi (Diptera: Psychodidae: Phlebotominae), an endemic species in the Orinoquia region of Colombia.

Lutzomyia antunesi has been commonly reported in outbreaks of cutaneous leishmaniasis (CL) in the Orinoquia region of Colombia. The bionomics of this species were studied in the municipality of Villavicencio (Meta, Colombia). Sandflies were captured over the course of one week per month for one year in intradomiciliary, peridomiciliary and extradomiciliary housing areas. The captures were performed from 06:00 pm-06:00 am using CDC light traps and the females were processed for polymerase chain reaction (PCR) to detect Leishmania spp. A total of 22,097 specimens and 19 species were captured of which Lu. antunesi (89%) and Lutzomyia walkeri (5%) were the most abundant. Other species recognised as anthropophilic (Lutzomyia panamensis, Lutzomyia gomezi, Lutzomyia flaviscutellata and Lutzomyia fairtigi) were present in very low abundance (< 2%). Natural infection with Leishmania spp was detected using PCR in Lu. antunesi, Lu. panamensis and Lu. flavicutellata, showing infection rates of 1%, 4.8% and 7.5%, respectively. The present paper provides information on various ecological aspects of Lu. antunesi. An analysis of seasonality shows that this species increases in abundance in the hottest months (December, January and February), directly correlating with the maximum temperature and inversely correlating with precipitation. The natural infection rate is associated with the peaks of highest abundance.

Lutzomyia antunesi, probable vector de leishmaniasis cutánea en el área rural de Villavicencio / Lutzomyia antunesi as suspected vector of cutaneous leishmaniasis in the Orinoquian region of Colombia

Objetivo Definir los posibles vectores de leishmaniasis, teniendo en cuenta su abundancia e infección natural con Leishmania spp. en un área endémica de la zona rural de Villavicencio, Meta. Materiales y Métodos En la vereda La Reforma, donde se presentaron casos de leishmaniasis cutánea en caninos y humanos, se recolectaron con trampas CDC los flebótomos en el intra, peri y extradomicilio de 15 viviendas. Grupos de 1 a 3 hembras de la misma especie fueron procesados por PCR para la detección de parásitos de Leishmania spp. Resultados Se capturaron 1 304 flebótomos distribuidos en 9 especies de las cuales L. antunesi (75,6 por ciento) y L. walkeri (19,2 por ciento) fueron las más abundantes. Otras especies reconocidas como antropofílicas (L. panamensis y L. gomezi), se presentaron con abundancias muy bajas (< 2,4). La PCR detectó infección con Leishmania spp. en dos grupos de L. antunesi (total= 123 hembras procesadas). Conclusiones L. antunesi por su abundancia e infección natural con Leishmania spp. podría estar involucrada en la transmisión de la leishmaniasis cutánea en un área rural al suroeste del municipio de Villavicencio.

Objective Identifying probable cutaneous leishmaniasis vectors in a rural area a few kilometres from the city of Villavicencio, taking the relative abundance of sand-flies and their natural infection with Leishmania spphaving into account. Materials and Methods A CDC trap was used for sampling sand-flies in and around 15 dwellings. Pools of three females from the most abundant Lutzomyia species were used for identifying Leishmania spp. by PCR, with OL1 and OL2 primers. Results 1 304 sand-flies from nine species were captured, of which L. antunesi (75,6 percent) and L. walkeri (19,2 percent) were the most abundant. These was a low abundance of L. panamensis and L. gomezi anthropophilic species (<2,4 percent). PCR detected Leishmania spp. infection in two L. antunesi groups (total=123 processed females). Conclusions Due to the fact that L. antunesi was the most abundant species and was found to have Leishmania infection, it may be considered to be the main suspected cutaneous leishmaniasis vector in the rural area being studied. It is recommended that detailed studies of this species’ biology (including biting and resting behaviour) should be carried out, aimed at furthering vector control measures.

[Lutzomyia antunesi as suspected vector of cutaneous leishmaniasis in the Orinoquian region of Colombia]. / Lutzomyia antunesi, probable vector de leishmaniasis cutánea en el area rural de villavicencio.

OBJECTIVE: Identifying probable cutaneous leishmaniasis vectors in a rural area a few kilometres from the city of Villavicencio, taking the relative abundance of sand-flies and their natural infection with Leishmania spphaving into account. MATERIALS AND METHODS: A CDC trap was used for sampling sand-flies in and around 15 dwellings. Pools of three females from the most abundant Lutzomyia species were used for identifying Leishmania spp. by PCR, with OL1 and OL2 primers. RESULTS: 1 304 sand-flies from nine species were captured, of which L. antunesi (75,6 %) and L. walkeri (19,2 %) were the most abundant. These was a low abundance of L. panamensis and L. gomezi anthropophilic species (<2,4 %). PCR detected Leishmania spp. infection in two L. antunesi groups (total=123 processed females). CONCLUSIONS: Due to the fact that L. antunesi was the most abundant species and was found to have Leishmania infection, it may be considered to be the main suspected cutaneous leishmaniasis vector in the rural area being studied. It is recommended that detailed studies of this species' biology (including biting and resting behaviour) should be carried out, aimed at furthering vector control measures.