Temporal and Spatial Variations of Some Meteorological Parameters and Malaria Occurrence In Ekiti State, Nigeria

Malaria is a major public health burden in the tropics with the potential to significantly increase in response to weather/climate parameters variations. Some meteorological elements have been widely associated with the dynamics of malaria vector population and, therefore, with spread of the disease. However, at the local scale, there is lack of thorough understanding of the effects of these factors on malaria transmission. Most of the attempts to quantify this effect are based on proxy meteorological data acquired from satellites or interpolated from a different scale. This has led to possible doubt in the contribution of weather variations to malaria prevalence and transmission risk among others. This study makes use of meteorological data measured at the local scale with malaria occurrence collected at the same time and scale to explore the temporal and spatial variations of malaria occurrence with meteorological parameters in Ekiti State; a tropical rain forest, in Nigeria. This work makes use of medical data and meteorological data spanning six years period (2005-2010).The medical data collected include monthly diagnosed cases of malaria for ages less than 5years, above 5years, and those in pregnancy while meteorological data collected were monthly values of relative humidity (%), minimum and maximum temperature (°C) and rainfall (mm) for six local government areas of the State. Descriptive, quantitative and time series analysis were carried out on the dataset. Also, temperature and relative humidity threshold were assumed to know which threshold the occurrence of the disease is at maximum. The results show that, there was a weak correlation between weather parameters and number of malaria occurrence in pregnancy. While the correlations are strong with children (below 5yrs) and adults (above 5yrs). Malaria prevalence among children was higher in the rainy season and has a good correlation of 0.76 which shows that, children <5 years old, are more susceptible to malaria occurrence than those >5 years old as their correlation coefficient with rainfall is 0.70. Also, the results from temperature and relative humidity threshold shows significantly that malaria parasite develop more between the temperature range of (30.1-32)°c with corresponding relative humidity of (60.1-80)% than any other temperature and relative humidity threshold. These results further show that the inhabitants of these areas are susceptible to malaria occurrence as the weather conditions in the areas are favorable to development of malaria parasite. Keywords: Weather, malaria prevalence, time series, threshold