Malaria Test Positivity, Plasmodium Species Distribution, and Risk Factors in Ho Municipality, Ghana: A Retrospective Analysis of Seasonal and Demographic Trends (2020–2022)

Background: Malaria remains a major public health challenge in Ghana. However, heterogeneous transmission necessitates localized data for effective subnational targeting of control measures. The Ho Municipality, characterized by high rainfall and humidity ideal for year-round mosquito breeding, exemplifies a setting where such detailed epidemiological intelligence is needed but currently scarce. This study aimed to bridge this gap by analyzing facility-based trends to inform precision public health interventions in this vulnerable region.Methods: We conducted a retrospective cross-sectional study, performing a census of all available malaria microscopy records from three major healthcare facilities in Ho Municipality over 36 months (January 2020–December 2022). Data were extracted from both paper-based logbooks and electronic health records. We employed descriptive statistics and multivariable regression analyses—specifically, a log-linear model to identify factors associated with parasite density (presented as Geometric Mean Ratios, GMR) and a Poisson regression model to identify factors associated with test positivity (presented as Adjusted Prevalence Ratios, APR). All models were adjusted for age, sex, facility, and year.Results: Among 27,171 tests, the overall test positivity rate (TPR) was 8.8%, showing a decline from 9.9% in 2020 to 7.2% in 2022. Significant disparities were observed: school-age children (5-12 years) had the highest TPR (18.0%), and a fourfold disparity existed between Ho Municipal Hospital (21.0% TPR) and Ho Teaching Hospital (5.2% TPR). Transmission peaked seasonally in August (13.9% TPR). Plasmodium falciparum was dominant (79.9% of confirmed cases). School-age children and adolescents demonstrated significantly higher parasite densities than adults (aGMR=3.69 and aGMR=3.57, respectively). Regression confirmed school-age children (aPR=3.26) and adolescents (aPR=3.49) as the highest-risk groups, with a significant age-sex interaction revealing elderly females were also at markedly increased risk (aPR=2.15).Conclusion: This study identifies persistent, significant disparities in malaria burden linked to specific age groups, sex, and health facilities in Ho Municipality. These findings underline the urgent need for a targeted intervention strategy, including school-based chemoprevention programs, enhanced diagnostic support and staffing for high-burden facilities, and pre-emptive vector control ahead of peak rainfall seasons to accelerate progress towards malaria elimination.