Keywords
Malaria, Seasonal Variation, annual trend, IDSR, Sierra Leone.
Abstract
Background: Malaria is the world’s deadliest mosquito-borne parasitic disease. An endemic disease in Sierra Leone it poses severe public health problems with stable and perennial transmission in all parts of the country. Worldwide, there were an estimated 241 million cases and 627,000 deaths from malaria in 2020. Many of these cases were caused by P. vivax which is rare in sub-Saharan Africa. The whole population in Sierra Leone is at risk of malaria and 22% of deaths among children and adults less than 70 years in 2020 were caused by malaria, mostly caused by P.falciparum. This study aimed to estimate malaria trends and seasonal variation using the Integrated Disease Surveillance and Response (IDSR) data (2012 – 2020) in six districts across the four regions.
Methods: The IDSR data that was collected and stored in the District Health Information System (DHIS-2) database over ten years (2011-2020) was used for this study. Statistical analysis was performed using R software for Time Series Analysis (TSA) on data from six districts across the four regions in Sierra Leone.
Results: The upward trend in positive malaria cases was statistically significant. The upward trend in positive cases was about 0.55% per year; compared to an estimated population growth of 2.1%, cases per 100,000 appeared to be declining, even though the total number of cases was increasing. Cases reported at hospitals and PHU (public health units) was highest in 2013 (1,007,356 cases in a population of 3,164,498) and least in 2020 (943,214 cases in a population of 4,222,328).
Seasonal variation in cases varied geographically with peak numbers recorded in the second quarter (beginning of the rainy season) in South-East and Northern Districts, but a peak in the third quarter (late rainy season) in the Western Area Urban.
Conclusion: The study found a high disease burden over the ten-year period in which the upward trend in positive malaria cases was statistically significant. There are seasonal variations across the four regions. The Sierra Leone National Malaria Control Program (NMCP) should be robust in monitoring the intervention activities to ensure compliance. Consistent support and regular refresher training on IDSR are also needed.
Citation
George AM, Kargbou A, Wadsworth R, Kangbai JB (2023) Trends and Seasonal Variations for Confirmed Malaria Cases for Sierra Leone for 2012 – 2020. SM J Public Health Epidemiol 6: 4.