Prevalence and Risk Factors of Waterborne and Foodborne Protozoan Pathogens in Kenya: A One Health Perspective.

Intestinal infections affect approximately 450 million people globally, predominantly impacting children and immunocompromised individuals in low- and middle-income countries (LMICs) due to inadequate water, sanitation, and hygiene (WASH) conditions, poverty, malnutrition, and low literacy. In Kenya, the prevalence of intestinal infections is elevated by warm tropical climates and socioeconomic factors. This scoping review evaluates the national prevalence, risk factors, and contamination sources of intestinal protozoa in Kenya, using a One Health approach to synthesize existing data from various human, animal, and environmental studies. A comprehensive literature search identified 292 studies, of which 67 met the inclusion criteria, covering the period from 1966 to 2024. The review found that most studies utilized stool microscopy, a method with limited sensitivity, and largely focused on vulnerable human populations, with minimal investigation into environmental reservoirs. Key protozoa identified included Entamoeba histolytica, Cryptosporidium, and Giardia, with transmission driven by poor WASH conditions, environmental factors, and close human-animal interactions. The findings highlight significant gaps in environmental surveillance and suggest the need for a robust, integrated One Health approach to better understand and control protozoan infections in Kenya.