スリランカの都市部における野外調査：ネッタイシマカの産卵に対するセメントの種類の影響

Dengue is a rapidly expanding vector-borne disease transmitted primarily by Aedes mosquitoes, which often breed in artificial containers. Urban construction sites, with their abundance of water-holding surfaces, are increasingly recognized as key breeding habitats. This study presents the first field-based evaluations of how specific construction materials, particularly cement types, influence mosquito oviposition behavior.

A seven-month field-based, randomized controlled experiment (September 2024-March 2025) was conducted across three Grama Niladhari divisions (Kolonnawa, Salamulla, and Orugodawatta) in Colombo District, Sri Lanka. A total of 480 ovitraps using four substrate types, Control (plastic), Blended Hydraulic Cement (BHC), Ordinary Portland Cement (OPC), and Portland Limestone Cement (PCC), were deployed in indoor (n = 4) and outdoor (n = 4) settings at 20 randomly selected households per GN division. Water quality parameters (pH, turbidity, conductivity) were recorded at trap placement. Egg counts were analyzed using a Zero-Inflated Negative Binomial (ZINB) regression model.

Traps containing BHC and PCC substrates had significantly fewer eggs than controls (BHC: β = -0.402, P = 0.014; PCC: β = -0.527, P = 0.001) and showed a higher likelihood of zero-egg presence (BHC: β = 1.025, P = 0.002; PCC: β = 0.941, P = 0.003). Outdoor traps had higher egg counts than indoor ones (β = 0.326, P = 0.021). Among water quality factors, only conductivity was significantly associated with egg counts (P = 0.036).

The BHC and PCC cement types significantly deterred Aedes oviposition compared to other substrates, indicating that construction materials can influence mosquito breeding behavior.