Altitudinal distribution and species richness of triatomines (Hemiptera:Reduviidae) in Colombia.

Background: Chagas disease is considered to be endemic in up to 40% of the territory of Colombia, and to date 27 triatomine species have been reported the country. The purpose of this study was to update the geographical distribution of triatomine species in Colombia and assess the species richness patterns and their altitudinal distribution.

Methods: Occurrence data were compiled between 2007 and 2020, including from reports of entomological surveillance from the Instituto Nacional de Salud (INS), the Centro de Investigaciones en Microbiología y Parasitología Tropical (CIMPAT) at Universidad de Los Andes and a review of the literature. Geographic Information Systems (GIS) were used to describe general species richness patterns of the Triatominae subfamily. To establish the altitudinal distribution of the triatomine species, ranges were obtained from reports with unique elevation values. A generalized linear model was fitted, based on a Poisson distribution, to test the relation between triatomine species richness and Chagas disease cases (2012-2019).

Results: An updated geographical and altitudinal distribution for triatomine species in Colombia was established, with 507 municipalities added to the previously known distributions. The greatest triatomine richness in Colombia was found to be concentrated in the northeastern region of the country, extending towards the center to the departments of Arauca, Casanare and Meta. Regarding the altitudinal distribution, the study revealed that the species Rhodnius prolixus and Triatoma dimidiata have the greatest altitudinal ranges. The data also suggest a positive relation between species richness and number of Chagas disease cases reported per department.

Conclusions: Altitudinal ranges for 17 triatomine species found in Colombia are presented. Species richness and species composition patterns are also described, and areas with a higher risk of transmission based on the relation found with Chagas disease cases are highlighted. This updated distribution reveals that Panstrongylus geniculatus is the triatomine with the largest presence by municipalities in Colombia, being reported in 284 municipalities, followed by Rhodnius prolixus in 277 municipalities.