Environmental and anthropic factors influencingAedes aegyptiandAedes albopictus(Diptera: Culicidae), with emphasis on natural infection and dissemination: Implications for an emerging vector in Colombia
Authors: Juan S Mantilla-Granados , Karol Montilla-López , Diana Sarmiento-Senior , Elver Chapal-Arcos , Myriam Lucía Velandia-Romero , Eliana Calvo , Andrés Morales Carlos , Jaime E Castellanos 
Published: October 2024

Background

Viruses such as dengue virus (DENV), Zika virus (ZIKV), and chikungunya virus (CHIKV) pose major threats to human health, causing endemic, emerging, and reemerging diseases. These arboviruses have complex life cycles involvingAedesmosquitoes, driven by environmental, ecological, socioeconomic, and cultural factors. In Colombia,Aedes aegyptiis the primary vector, butAedes albopictusis expanding across the country. Understanding the unique characteristics of each species is crucial for managing arbovirus spread, particularly in areas where they coexist.

Methodology/Principal Findings

We conducted an entomological survey ofA. aegyptiandA. albopictus(larvae, pupae, and adults) in urban and rural areas of four municipalities across different elevations (200–2200 meters above sea level) in Colombia. Household conditions and knowledge of DENV were assessed through interviews. FemaleA. albopictuswere tested individually for arbovirus RNA, whileA. aegyptiwere tested in pools. Both species were found up to 2100 masl.A. aegypticomprised 78% of the immature forms collected, whileA. albopictusmade up 22%. Larvae from both species coexisted in common artificial breeding sites in urban and rural areas, with no evidence of competition.A. albopictuspreferred rural areas, lower elevations (<1500 masl), high precipitation (>270 mm), and poor household conditions, whileA. aegyptiwas more abundant in urban areas, intradomicile environments, and areas with moderate precipitation (100–400 mm). Biting risk was higher forA. aegypti(0.02–0.22 females per person), particularly in urban areas, whileA. albopictusexhibited lower biting risk (0.001–0.08), with the highest values in rural Patía. Natural infections of DENV (12.4%) and CHIKV (12.4%) were found inA. aegypti, whileA. albopictusshowed CHIKV (41.2%) and DENV (23%) infections, with virus dissemination to the legs and salivary glands.

Conclusions/Significance

Integrating household conditions and community knowledge with environmental data can enhance predictive models for vector presence and guide surveillance and educational strategies. Our findings highlight the need to considerA. albopictusas a potentially significant arbovirus vector in Colombia, especially given the presence of arboviruses in its salivary glands, its use of artificial breeding sites, its biting risk inside homes, and its differing ecological preferences and seasonal associations compared toA. aegypti.

AUTHOR SUMMARY

In this study, we investigated the ecological and epidemiological dynamics ofAedes aegyptiandAedes albopictusand their natural infection with DENV, ZIKV, and CHIKV in Colombia. An entomological survey conducted across four municipalities revealed distinct environmental and human-related factors influencing the distribution and abundance of these species.A. aegyptiwas more abundant in urban environments, favoring areas with lowest precipitation and a range of household conditions, whileA. albopictuswas more common in rural areas with higher precipitation and poorer household conditions. Both species were naturally infected with DENV and CHIKV, withA. albopictusshowing the ability to disseminate, as indicated by their presence in the legs and salivary glands. Our findings underscore the importance of understanding species-specific ecological characteristics and incorporating community knowledge into predictive models to improve vector surveillance and control strategies, particularly in regions where both species coexist and contribute to arbovirus transmission.