Asymptomatic Plasmodium infection in selected Low Transmission Setting of Dedo District, South-west Ethiopia

Abstract

Background: Regardless of decades of sustained control efforts, malaria remains a major cause of morbidity, mortality and socio-economic problems in Ethiopia. Even though it shows a remarkable decline in the last decade and given that elimination efforts are underway, asymptomatic infections may pose major challenges to the aimed elimination program of the country by 2030. Objective: The aim of this study was to determine prevalence of asymptomatic Plasmodium infection and assess trends of malaria in selected low transmission setting of Dedo District, Ethiopia. Methods: Repeated, community based cross-sectional surveys were conducted among 150 households (743 study participants) in May and October 2018 in Waro Kolobo kebele of Dedo district, Ethiopia. Pre-tested semi-structured questionnaire was used to collect data on socio-demographic characteristics of the study participants and the associated risk factors. Finger prick blood samples were taken from all study subjects to detect malaria parasite by microscopy and rapid diagnostic tests (RDT). Additionally, a retrospective study was conducted in offele health center to assess a five-year malaria trend (2014-2018) in the study area. Data were entered to Epi-data and Statistical analysis was performed using SPSS version 20. Descriptive statistics were utilized to summarize demographic profile of the study participants. Bivariate and multivariable logistic regression analysis were employed to determine the association between independent variables and the outcome/dependent variable. P-value ≤ 0.05 were considered as statistically significant. Results: In the two cross-sectional surveys, a total of 743 study participants were included. In the first survey, which included 370 study participants, none of the blood samples collected and analyzed by microscopy and RDT were positive for Plasmodium infection. In the second cross-sectional survey, (6/373) of the blood samples were positive using microscopy but were negative by the RDT. Almost all the households included in the surveys had at least one LLIN. However, only 62.4 and 69.4% of the study participants used LLIN the previous night before the survey in the first and the second survey respectively. Educational status AOR (2.4, 95% CI: 1.297-4.617; p=0.006), age group (AOR 2.3, 95% CI: 1.307-4.237; p=0.004) and LLIN utilization (AOR 3.5, 95% CI: 1.964-6.266; p<0.001) were significantly associated with history of malaria in the preceding one year. Conclusion: The prevalence of asymptomatic malaria infection was 6/373 in the study area. Although the LLINs coverage is high, about a third of the residents did not use LLIN the previous night before the survey. Long lasting insecticide nets utilization assessment is required to further suppress the transmission of malaria.