Title : Modeling climate effects on mosquito abundance in an arid environment: Link to vector-borne disease risk
Abstract:
Background: Vector-borne diseases (VBDs) are increasingly recognized in Qatar, where mosquito-borne diseases have been reported more frequently in recent years. Qatar’s arid climate, with occasional rain, high humidity, and mild winters, creates windows suitable for mosquito activity and transmission. Unlike tropical regions where VBDs are well studied, Qatar’s unique desert climate remains underexplored, yet evidence shows that all major genera (Aedes, Anopheles, Culex) can find viable transmission periods, raising concern for future VBD risks under climate change.
Methods: We applied a Distributed Lag Nonlinear Model (DLNM) within a Zero-Inflated Negative Binomial framework to monthly mosquito surveillance data (2022-2024) across multiple sites in Qatar. Average monthly climate data included minimum, mean, and maximum temperature, relative humidity (RH), and rainfall. The DLNM assessed nonlinear and delayed climate effects on mosquito abundance, adjusting for location, seasonality, and trap effort, using the dlnm package in R.
Results: Temperature showed nonlinear effects on mosquito abundance, with moderate mean and minimum temperatures immediately increasing mosquito abundance and sustaining higher risk over the longer term, while extreme summer heat consistently suppressed abundance. Relative humidity strongly influenced mosquito populations, with low RH (33-45%) significantly suppressing counts and high RH (62-66%) increasing risk over the longer term. Rainfall, even at low to moderate levels (>0-3 mm), triggered sharp short-term increases in abundance, highlighting the sensitivity of mosquito populations to occasional rain in arid environments. Higher rainfall also had a positive but weaker effect compared to lower rainfall. Rainfall effects declined over time, indicating rainfall drives immediate but not sustained increases in mosquito populations.
Conclusion: This model identifies climatic thresholds and lag periods where mosquito abundance peaks, providing evidence to anticipate periods of elevated risk. These findings support climate-based preparedness by informing vector control planning, strengthening surveillance, guiding public health policy, and anticipating future mosquito abundance and VBD risk across Qatar and the wider MENA region.
