Climatic Variables and the Persistence in Malaria Morbidity in Mutale Municipality, South Africa: A 19-year Data Analysis

Statement of the Problem: The malaria control program community of South Africa received a seemly blow as an awakening call on the reality of the country’s target to eliminate malaria in the year 2018. The north-eastern part of the country, comprising of the Limpopo Province, have recorded a sudden rise in the number of malaria morbidity and mortality in the 2017 malaria season. This paper aims at retrospectively and prospectively exploring the impact of climate variability, among other factors, driving the persistent transmission of malaria in the Limpopo Province of South Africa. Methodology & Theoretical Orientation: A time series and multivariate analysis was performed on monthly total rainfall, monthly mean maximum and minimum temperature and monthly case data of malaria in the Limpopo Province for the period of 2000 to 2017. The Rossby Centre Regional Climate Model (RCA₄ RCM) was used to perform climate change projections for rainfall and near-surface (2m) temperature. Findings: The time series analysis indicated that an average of 629.5mm of rainfall was received over the period of study. The rainfall has an annual variation of about 0.46%. Both maximum and minimum temperature showed a positive increasing trend in their mean. Spearman’s correlation analysis indicated that all climatic variables are positively correlated with malaria morbidity. Further analysis revealed that total monthly rainfall and monthly minimum temperature, with one month lag, were the most significant climatic variable influencing malaria transmission. More particularly, malaria morbidity showed a strong relationship with episodes of rainfall above 800 mm and above 5-year running mean of rainfall. Furthermore, the RCA₄ RCM projections indicated that annual rainfall in the province might become 0% - 15% drier. Seasonally, the western part of the province might become 5% wetter in December – February (DJF) and 5% drier in the eastern part in March – May (MAM), June – August (JJA) as well as <20% dryer in September – November (SON). Near-surface temperature is projected to increase between +1.5°C - +2.5°C in 29-year period. Conclusion & Significance: Adequate understanding of climatic variables dynamics retrospectively and prospectively is imperative in seeking answers to malaria morbidity, among other factors, particularly in the wake of the sudden spike of the disease in the province.