Prevalence of Infection and Associated Factors After a Decade of Mass Drug Administration in the Amhara Regional State, Northwest Ethiopia: A Cross-Sectional Study

BACKGROUND:

Schistosoma mansoni remains a significant public health problem in Ethiopia despite over a decade of deworming targeting school-aged children (SACs), often neglecting adults. Prevalence surveys relying on the Kato-Katz (KK) technique may underestimate infection, highlighting the need for updated data using more sensitive diagnostics.

METHODS:

A cross-sectional study was conducted from February to June 2023 among 634 SACs and 558 adults in the Amhara Regional State. Data on risk factors were collected via structured questionnaires. infection was assessed using KK and real-time polymerase chain reaction (RT-PCR) on stool, and point-of-care circulating cathodic antigen (POC-CCA) on urine. Egg counts from 2 KK readers were averaged to determine final eggs per gram (epg). Data were analyzed using Statistical Package for the Social Sciences version 21; descriptive statistics and poisson regression model with cluster-robust standard errors were analyzed.

RESULTS:

A total of 452 SACs (71.3%) and 330 adults (59.1%) were tested positive for at least by one diagnostic method. Prevalence in low-, moderate-, and high-transmission settings was 56.9%, 81.5%, and 95.5% among SACs, while it was 50.5%, 55.5% and 96.5% among adults, respectively. KK detected light, moderate and heavy infections among 170 (26.8%), 62 (9.8%) and 29 (4.6%) SACs, respectively, while it was 96 (17.2%), 38 (6.8%) and 3 (0.5%) in adults, respectively. SACs had higher epg than adults (148.0 vs 96.6; ). School-aged children who swam or bathed in surface water had a significantly higher prevalence of infection (prevalence ratio (PR) = 2.679,  = .002). Similarly, SACs who always participated in agricultural activities (PR = 1.266,  = .037) and those who were not aware of schistosomiasis (PR = 1.364,  = .038) had a higher prevalence of infection compared with their counterparts. Among adults, crossing surface water barefoot was significantly associated with a higher prevalence of infection (PR = 1.481,  = 0.018).

CONCLUSIONS:

S. infection remains highly prevalent among both SACs and adults in the study area. In SACs, key risk factors included swimming or bathing in surface water, participation in agricultural activities and lack of awareness about the disease, while in adults, crossing water barefoot increased infection risk. These findings highlight the need to expand deworming programs to adults and implement targeted interventions, including health education and improved water access, to reduce transmission in endemic areas.