Etiology and Epidemiology of Travelers' Diarrhea among US Military and Adult Travelers, 2018-2023.

Travelers' diarrhea has a high incidence rate among deployed US military personnel and can hinder operational readiness. The Global Travelers' Diarrhea study is a US Department of Defense--funded multisite surveillance effort to investigate the etiology and epidemiology of travelers' diarrhea. During 2018-2023, we enrolled 512 participants at partner institutions in 6 countries: Djibouti, Georgia, Egypt, Honduras, Nepal, and Peru. Harmonized laboratory methods conducted at each partner institution identified >1 pathogens, including Escherichia coli (67%-82%), norovirus (4%-29%), and Campylobacter jejuni (2%-20%), in 403 (79%) cases. Among cases, 79.7% were single infections, 19.6% were double infections, and 0.7% were triple infections. The most common enterotoxigenic E. coli colonization factors identified were CS3 (25%) and CS21 (25%), followed by CS2 (18%) and CS6 (15%). These data can inform best treatment practices for travelers' diarrhea and support US military health readiness.