Describing and analysing the association between meteorological variables and adult 'Aedes aegypti' mosquitoes

The aim of this study was to describe the association between meteorological factors and the abundance of adult 'Aedes aegypti' mosquitoes, over 5 year period, from 2006 to 2010 in Jeddah, Saudi Arabia. Daily meteorological data and the adult 'Aedes' mosquito counts and identification were collected and retrieved from the Presidency of Meteorology and Environment (PME) and the laboratory of mosquitoes, which belongs to Jeddah Municipality. Different methods were used to verify the associations. Descriptive analysis provided a comparative view of adult 'Aedes' mosquitoes and meteorological variables. Spearman correlation analysis was used to examine the association. The meteorological data were related to adult 'Aedes' mosquito numbers on a weekly basis. The number of adult 'Aedes' mosquitoes increased rapidly about two weeks after the week of rainfall, and sometimes after one week. Most of the meteorological variables associated negatively with the number of mosquitoes in most of the years of epidemic except 2007. In 2007, all meteorological variables considered in this study were positively correlated with the number of mosquitoes, and the most significant correlation was between the weekly averages of maximum relative humidity and the number of mosquitoes (P = 0.49). It was found that average weekly maximum temperature, average weekly minimum relative humidity and average weekly maximum relative humidity were not the main determinant factors in the abundance of adult 'Aedes' mosquitoes, while rainfall and average weekly minimum temperature played determining roles in the abundance of adult 'Aedes' mosquitoes. The study findings can help to improve current dengue fever surveillance system in Jeddah for more accurate forecasting. Every trap that is used to capture adult mosquitoes must have devices for measuring temperature and relative humidity to give a better understanding of the impact of climatic conditions on the adult mosquito abundance.