Microscopic prevalence and risk factors of asymptomatic malaria in Gorgora, western Dembia, Northwest Ethiopia: exploring hidden threats during minor transmission season

Abstract Background Malaria poses a significant public health threat globally, particularly in African regions, where asymptomatic malaria is a considerable logistic problem. Individuals with asymptomatic malaria do not seek treatment, and thus they are invisible to health facilities and represent a substantial hidden reservoir of Plasmodium species. This study aimed to determine the prevalence of asymptomatic malaria and its associated factors in Gorgora, western Dembia district, Northwest Ethiopia. Methods A community-based cross-sectional study was conducted from May to June 2023 in the Gorgora area, Western Dembia district, Northwest Ethiopia. Data were collected using a semi-structured questionnaire. Giemsa-stained blood smear microscopy was employed for the diagnosis of Plasmodium species. The data were entered into Epi Data version 4.6 and exported to SPSS version 25 for analysis. Bivariate and multivariable binary logistic regression analyses were conducted to identify associated factors. Results Among the 357 individuals who participated in this study, 9.2% (33/357) [95% CI 6.40–12.70: p = 0.000] were confirmed to be infected with Plasmodium species. Plasmodium falciparum and Plasmodium vivax accounted for 66.7% and 33.3%, respectively. Not using bed nets [AOR = 7.3, 95% CI 2.08–23.46, p = 0.006)], previous malaria history [AOR = 2.6, 95% CI 1.01–6.45, p = 0.041], outdoor activities at night [AOR = 8.3, 95% CI 3.21–21.30, p = 0.000], and family size [AOR = 3.3, 95% CI 1.18–9.22, p = 0.023] were significantly associated with asymptomatic malaria (p < 0.05). Conclusions A considerable proportion of asymptomatic Plasmodium infections was found which likely act as a reservoir of transmission. This has implications for ongoing malaria control programmes that are based on the treatment of symptomatic patients and highlight the need for intervention strategies targeting asymptomatic carriers. Not using bed nets, engaging in outdoor activities at night, and having a family size of more than five increased the odds of developing asymptomatic malaria. The district health office and health extension workers should collaborate to promote the regular use of mosquito bed nets among community residents.