Seasonal Prevalence of Malaria, Fever, Anaemia and Factors Associated with Malaria Prevalence among Children Less than Five in an Area with Prolonged Malaria Transmission in Ghana

Background: Globally, malaria and anaemia are major causes of morbidity and mortality among children. As part of the millennium declaration, countries enjoined themselves to have halted and begun to reverse the incidence of malaria and other diseases by 2015. In 2006, Ghana started implementing malaria control strategies that involved free distribution of Long Lasting Insecticide Nets (LLINs), early detection and prompt appropriate treatment with Artemisinin-based combination therapies (ACTs). This study was set out to assess the prevalence of malaria, anaemia, ownership and use of LLINs at the end of the low transmission (pre-rainy season) and high transmission (post-rainy season) seasons in 2015. It also reported on factors associated with malaria prevalence in the Hohoe municipality of Ghana.

Methods: Two community-based cross-sectional surveys were undertaken among children less than five years in 30 communities. Information was collected on the background of the children, ownership and use of LLINs, history of fever and antimalarial drug used at home. Anthropometric indices and axillary temperature were measured, as well as blood film for malaria parasites and haemoglobin levels. Data analysis was done using z test to compare differences in proportions, t-test to compare differences in means and multiple linear regression to determine association between dependent and independent variables.

Results: A total of 1915 and 1697 children were screened. The prevalence of malaria by RDT in the pre- and post-rainy seasons were 217 (11.3%) and 676 (39.8%) respectively, and using microscopy were 148 (7.7%) and 451(26.6%) respectively. Malaria parasitaemia prevalence was significantly lower in the pre- compared to post-rainy season (7.7% vs. 26.6%; p<0.001). Ownership of LLIN was high, however, similar in the pre- and post-rainy seasons (83.2% vs. 84.1%; p= 0.466). Usage of LLIN was significantly lower in the pre- than the post-rainy season (68.3% vs. 72.8%; p=0.003). Anaemia (Hb<8.0 g/dl) was significantly higher in the pre- compared to the post-rainy season (11.1% vs. 8.9% p=0.028). Gametocyte prevalence was similar in pre- and post-rainy seasons (0.4% vs. 0.3%, p=0.677) respectively. Malaria prevalence was found to be associated with fever (temperature≥37.5°C) (p=0.029), and ACTs use for suspected malaria during the pre-rainy season (p=0.027).

Conclusion: Gametocyte prevalence is an indication that malaria is transmitted throughout the year though highly seasonal. Treatment of suspected malaria with ACTs can reduce malaria prevalence. Overall, LLIN ownership and use was high but did not meet the millennium targets of 100% ownership and 85% usage. Our findings suggest that in the low transmission season, introduction of systematic detection and treatment of asymptomatic carriers and in the high transmission season, Seasonal Malaria Chemoprevention (SMC) together with the existing interventions could impact on malaria burden to such a level that elimination can be considered. Further studies are required to determine why lower usage of LLINs and higher prevalence of anaemia in the low transmission season.