Pathogens, reservoirs, and vectors involved in the transmission of vector-borne and zoonotic diseases in a Colombian region.

The ecology of vector-borne diseases (VBDs) is an important system of great complexity, which involves the knowledge about the pathogens and animal species entailed in maintaining transmission cycles in a given locality, including those that act as vectors and reservoirs for the transmitted pathogens. To understand the ecology of some VBDs, we studied vectors, reservoirs, and pathogens of different VBDs, including dengue, leishmaniasis, Chagas disease, malaria, Zika, and chikungunya in the municipality of La Mesa, Cundinamarca, Colombia, a locality close to the capital, Bogotá. Vectors and mammals were sampled in urban and rural areas between May and August 2019. Molecular analyses were performed for the detection of pathogens in mammals and vectors, and of blood-meal sources in insects. Several vectors and mammals collected in this study have been involved in pathogen transmission cycles or may have a potential role in them. The findings of this study suggest that in the municipality of La Mesa, there are both vector and potential reservoir species, which are or could be implicated in the maintenance of the cycles of vector-borne diseases such as leishmaniasis and Chagas disease. Although arbovirus infections, such as dengue, are reported in the municipality, arbovirus presence was not detected. These findings highlight the importance of ongoing surveillance of vectors and associated control operations in La Mesa, of relevance to other locations where vectors and animal hosts also occur.

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.