Spatial distribution, larval density and physicochemical characteristics of mosquito breeding sites in Delta State, Nigeria

The spread of mosquito breeding sites and physicochemical characteristics (PCC) of the sites in selected Local Government Areas (LGAs) in Delta State were spatially mapped. PCC of the site was read using multiple parameter device and GPS devices were used to determine spatial distribution of mosquito larvae breeding sites (April, 2020 - July, 2022). A total of 715 breeding sites were evaluated and only 466 were positive of mosquito larvae. Mosquito density was calculated in situ using 350 ml deep ladles. Results revealed that 1) mosquito densities were highest in Isoko North LGA; 2) mosquito density was high in the western communities of all LGAs except in Ukwani and Aniocha South; 3) pH was slightly acidic in all LGAs except in Isoko North; 4) Water in Ukwani and Ika North were turbid (62 and 70%), puddles (37 and 40%) and had more of Anopheles mosquitoes whereas in other LGAs, water was clear, of diverse habitats and equally had more of Anopheles mosquitoes. Result of geospatial model show that mosquito density, temperature and pH were within the ranges of 1.60-29.95, 0.00-37.4oC, and 0.0-9.0 respectively. Ika North East accounted for the lowest temperature and pH recorded in patches on the map of spread. Water temperature (To), pH, total dissolve solids and conductivity were optimum for mosquito density. To and pH were highest in breeding sites where Anopheles, and Culex, or Culex and Aedes mosquitoes coexisted. In conclusion, vector control programs should focus on manipulating these breeding site factors to minimize mosquito abundance.