Retrospective study of seasonal trends of malaria reported cases in Kano State, Nigeria

Abstract

Malaria is one of the leading causes of morbidity and mortality in Nigeria. Incidence of the disease varies over the space and time. This study investigates the seasonal trend of malaria incidence in Kano State. Data for four years (January 2010 to December 2013) was extracted from the routine consultation and recorded case sheets. A 12x4x2 three-way Analysis of Variance (3-way ANOVA) between subject effects factor design was performed on the raw data to explore the significance mean differences of malaria over time. Result revealed that there were 3,062,812 confirmed malaria cases reported during the period under study. The highest recorded cases were in the year 2011 with 858,061 cases or 28.02%. Mean monthly cases showed that incidence concentrate during the rainy season between May and October with the peak month being September of the years under investigation. For forms of malaria, uncomplicated cases accounts 90.7% and severe malaria constitutes the remaining 9.3%. Further, results from Analysis of Variance (3-way ANOVA) showed strong statistical main effect for months (F = 3.27, P = 0.0001); strong statistical significant main effect for years under study (F = 1.03, P = 0.0001) and strong statistical significant main effect for forms of malaria (F = 8.80, P = 0.0001). In addition, the interaction effect between the three independent variables (Months, Years and Form of Malaria) was found to be significant (F = 2.19, P = 0.0001). This interaction was followed up by conducting multiple comparison tests using Bonferroni correction. Results confirmed that the mean differences of months and years were statistically significantly difference. The study indicates that malaria is a common illness occurring all year round and therefore recommends for urgent intervention strategies to arrest the burden of the disease.

Keywords: Burden, Morbidity, Mortality, Severe Malaria, Uncomplicated Malaria