Serological and parasitological assessment of onchocerciasis transmission and associated factors at Abeshige district, Guragae zone, Southwest Ethiopia: Cross-sectional study
Authors: Arega Sisay Dagnew , Feleke Sindew Mekasha , Zeleke Tadesse Kebede , Mekonnin Wuletaw Tadesse 
Published: February 2023

Abstract

Background: One of the crippling neglected tropical diseases, onchocerciasis (river blindness), is caused on by the skin-dwelling filarial nematode Onchocerca volvulus, an important vector-borne neglected tropical disease transmitted by the bite of infected black fly. The adult worm lives in the subcutaneous tissues producing thousands of microfilariae that cause skin and eye disease. In Ethiopia, onchocerciasis elimination program has been under way for more than two decades and has been mainly targeting hyper-endemic districts. However, the transmission status in hypoendemic areas wasn’t assessed and targeted for intervention. This study was therefore carried out to assess onchocerciasis transmission status and associated factors in the hypoendemic Abeshige district and generate evidence for program decision making.
Objective: This study assessed onchocerciasis transmission status and associated factors in first line villages of Abeshige districts.
Method: A community-based cross-sectional study was conducted in three purposively selected first line villages of the Abeshige district from April to May 2022. The study participants (n=300, 100 for each village) were randomly selected and enrolled using single proportion formula. Demographic information and participant’s knowledge, attitude and practices data were collected using a standard questionnaire. Finger prick blood sample for serologic test and skin snip samples for microfilariae examination were collected and examined. Data was entered into Epi-info software version 7.1, and imported to SPSS version 26 software for analysis. The association between dependent and independent variables was done using bivariate logistic regression and the P-value <0.05% was considered statistically significant.
Result: out of the 300 examined study participants, 31 (10.1%), 17 (5.7%), 1 (0.33%) were positive by Ov-16 ELISA, Ov-16 RDT and skin snip microscopy, respectively. The participants have poor knowledge, attitude and practice about disease causation, transmission and prevention. None of the study participants have demonstrated palpable nodules, skin depigmentation, blindness, eye inflammation and itching. Age, sex and distance from the river were the independent variables those had significant associations with positivity for Ov-16 ELISA results (P<0.05).
Conclusion: the serological prevalence of onchocerciasis was above the WHO recommended threshold (5%) for the implementation of elimination programs. Age, sex and distance from the fast-flowing rivers had significantly associated with positivity of Ov-16 ELISA test. The majority of the population had poor knowledge, attitude and practice about onchocerciasis. Therefore, ivermectin treatment intervention is recommended to be implemented in the district to eliminate the disease. Inclusion of health education in the intervention program is also very important.