Mosquito Diversity and Public Health Risk in Kerala, India: A Synthesis of a Multi-District Survey
Source: Mathiarasan, L., Natarajan, R., Aswin, A. et al. Diversity and spatiotemporal distribution of mosquitoes (Diptera: Culicidae) with emphasis on disease vectors across agroecological areas of Kerala, India. Sci Rep 15, 30603 (2025). https://doi.org/10.1038/s41598-025-16357-y
Date: Received - 29 May 2025 | Accepted - 14 August 2025 | Published - 20 August 2025
Executive Summary
This document synthesizes the findings of an extensive entomological survey conducted across five agroecological districts of Kerala, India. The research reveals a remarkably diverse mosquito fauna, identifying 108 species, including 14 known disease vectors, which underscores the region's complex public health challenges. The study highlights the overwhelming predominance of Stegomyia albopicta (54.82% of all collected specimens), a highly adaptable vector for dengue and chikungunya, posing a significant and ongoing threat.
Key findings indicate that artificial, human-made habitats—such as discarded tires, plastic containers, and latex collection cups—are the primary breeding grounds, supporting greater species diversity than natural habitats and pointing to critical deficiencies in solid waste management. The Wayanad district was identified as a major biodiversity hotspot for mosquitoes, attributed to its unique ecological niches. The investigation also yielded significant scientific discoveries, including the description of a new species, Heizmannia rajagopalani, and the first regional records of several other species. The co-existence of multiple vectors for arboviruses, malaria, and filariasis creates a complex risk profile that necessitates comprehensive surveillance and targeted, ecologically-informed control strategies.
1. Overview of the Entomological Survey
The study was designed to conduct a comprehensive assessment of mosquito biodiversity, spatiotemporal distribution, and habitat preferences across diverse ecological settings in Kerala, India, a state known for its unique agro-geographical features and history of mosquito-borne disease (MBD) outbreaks.
2. Species Composition and Abundance
The survey revealed a rich and diverse mosquito fauna, highlighting a complex ecosystem of both nuisance species and medically important vectors.
Overall Diversity
A total of 108 mosquito species belonging to 28 genera were identified. The genus Culex exhibited the highest species richness (25.0%), followed by Anopheles (12.9%) and Stegomyia (10.2%).
Dominant Species
The vast majority of collected specimens were dominated by a few highly prevalent species:
| Species | Percentage of Total Collection | Known Significance
| Stegomyia albopicta | 54.82% | Primary vector for dengue, chikungunya, Zika
| Culex quinquefasciatus | 6.92% | Vector for lymphatic filariasis
| Hulecoeteomyia chrysolineata | 6.33% | Noted for diverse breeding patterns
| Armigeres subalbatus | 5.03% | Nuisance mosquito, prefers polluted water
Identified Disease Vectors
The study identified 14 known disease vector species, creating a multifaceted public health risk. The co-existence of primary and secondary vectors for various diseases complicates transmission dynamics.
While St. albopicta was abundant, other primary vectors were found in extremely low numbers, such as St. aegypti(1.43%), An. stephensi (0.06%), and An. culicifacies (0.01%). However, the study emphasizes that even low-density vector populations can sustain pathogen transmission cycles and cause outbreaks under favorable conditions.
3. Spatiotemporal Distribution and Biodiversity Hotspots
The distribution of mosquito species varied significantly across the five surveyed districts, revealing distinct biodiversity patterns influenced by local ecology.
District-Level Diversity
A core group of 19 species was found across all five districts, indicating shared environmental determinants that support widespread mosquito populations.
Prevalence Patterns
Stegomyia albopicta was the predominant species in all five districts. In the Thiruvananthapuram district, it accounted for an exceptionally high 77.29% of collected mosquitoes. The second-most dominant species varied by district, suggesting that "one-size-fits-all" vector control methods would be ineffective and require tailored, localized strategies.