Prevalence and assemblage of Giardia duodenalis in a case-control study of children under 5 years from Jimma, Southwest Ethiopia.

Giardia duodenalis is a common pathogenic intestinal protozoan parasite with high prevalence in developing countries, especially among children. The distribution of giardia assemblages among humans and their clinical relevance remains controversial. This study aimed to determine the prevalence and assemblage of Giardia among children under 5 years of age in Jimma, Southwest Ethiopia. Employing a case-control design, 606 children presenting with diarrhea at Jimma university medical center and Serbo Health Center were enrolled from December 2016 to July 2018 along with 617 matched controls without diarrhea. Giardia was detected and typed using real-time PCR. Univariate and multivariate regression analysis was performed. The total prevalence of Giardia was 41% (501/1223) and did not differ significantly between cases and controls (40% vs 42%). Prevalence increased by age, with the highest prevalence seen in children aged ≥ 25 months. Children without diarrhea with a history of diarrhea during the last month were more likely to be Giardia positive compared to children with no history diarrhea (OR 1.8 and 95%CI; 1.1-2.9). Regardless of current diarrhea symptoms, assemblage B predominated with 89%, followed by assemblage A (8%) and mixed infection assemblage A and B (3%). We report a high prevalence of Giardia by PCR detection in Jimma, Ethiopia, with assemblage B being predominant. There was a similar distribution of Giardia assemblages between children with and without diarrhea. Increasing age was a risk factor for Giardia infection. Community-based prevention and control strategies need to be employed to decrease the risk of giardia infection.