Bacterial and parasitic etiologies of diarrhea and the emerging role of Aeromonas spp. among children aged under 5 years in Addis Ababa, Ethiopia: a case-control study

Abstract

Objectives This study aimed to identify bacterial and parasitic etiologies, associated risk factors, and the contribution of Aeromonas spp. to under-five diarrhea in Addis Ababa, Ethiopia. Methods A health facility–based unmatched case–control study was conducted from October 2022 to April 2023 in four selected health centers. Stool samples from 163 diarrheal cases and 163 controls were examined for bacterial and parasitic pathogens. Sociodemographic, environmental, and behavioral data were collected using structured questionnaires. Logistic regression was used to assess associations, and attributable fractions were calculated to estimate pathogen-specific contributions to diarrhea. Results Enteric pathogens were detected more frequently among cases than controls (39.3% vs. 18.4%, p<0.005). Aeromonas spp. (14.4%) were the most commonly identified bacteria and were strongly associated with diarrhea (AOR =16.86). Giardia lamblia was also significantly associated (AOR = 7.47). The attributable fraction among the exposed was 94.1% for Aeromonas spp. and 86.6% for G. lamblia , with population attributable fractions of 13.6% and 4.8%, respectively. Larger household size, shared toilet use, and pet ownership were significant risk factors. Conclusions Aeromonas spp. may represent an emerging cause of childhood diarrhea in Ethiopia, underscoring the need for improved diagnostic consideration and targeted public health interventions.