David Lindholm

Background We evaluated the impact of infectious disease (ID) syndromes on US active duty (AD) servicemembers returning from overseas deployment (DEP), military training exercises (EXR), or short-term military travel (eg, temporary assignment of duty [TDY]). Methods We conducted a survey-based assessment of US AD servicemembers returning from DEP, EXR, or TDY between 2015 and 2019. Subjects completed a post-travel survey capturing symptoms of travelers’ diarrhea (TD), influenza-like illness (ILI), and febrile illness (FI). Risk factors associated with any ID syndrome (ie, either TD, ILI, or FI) that impacted daily activities were assessed using a logistic regression model with backward selection. Results One-third of servicemembers (654/1822) experienced an ID syndrome, and 26% (471/1822) reported a ≥50% reduction in activity level due to an ID syndrome (median duration, 3 days). TD was the most common ID syndrome experienced and accounted for 73% (346/471) of ID syndromes impacting daily activities. The greatest impact of ID syndromes was observed in servicemembers on DEP. Compared with servicemembers on EXR or TDY, those on DEP had a longer duration of travel and a delayed period of risk for ID syndromes. Multivariate analysis identified high-risk exposures (ie, environmental exposures, close contact with locals, consuming food from street vendors) and behaviors (ie, inability to sanitize hands before meals) that could be used to inform mitigation strategies. Conclusions ID syndromes result in a significant loss of productivity during military travel. Addressing modifiable risk factors and access to TD self-treatment in high-risk settings may help mitigate the impact of ID threats during military travel.