A cross-sectional analysis of clinical presentations of and risk factors for enteric protozoan Infections in an Active Duty Population during Operation Iraqi Freedom.

John W Downs,Mark S Riddle,Marshal R Monteville,James Herbst,Shannon D Putnam,Manal Mostafa,Louis E Antosek,David R Tribble,David M Rockabrand,John W Sanders,Gamal El Okla

doi:10.1186/s40794-015-0005-6

Abstract

BackgroundInfectious travelers’ diarrhea (TD) is a well-appreciated problem among service members serving abroad, particularly where infrastructure is limited due to ongoing combat operations, and efforts at sanitation and hygiene may not be considered an immediate priority. Bacterial and viral causes of travelers’ diarrhea are well-described among deployed service members, however, gastrointestinal protozoan infections among deployed service members are less well documented. This study’s purpose was to identify potential risk factors for, and clinical presentations of, enteric protozoan infections in an active duty military population deployed to combat operations in the Southwest Asia.MethodsA cross-sectional study of enteric protozoan infections among US service members deployed in Al-Asad Air Base, Iraq in support of Operation Iraqi Freedom (OIF) was conducted in summer 2004. Subjects were obtained through a randomized sector sampling scheme, and through presentations for care at the air base medical facilities. All study participants provided a stool sample, either diarrhea or solid, upon study entry and completed a questionnaire documenting demographic information, clinical symptoms of any prior diarrheal episodes, and health risk behaviors. Basic diagnostic microscopy for protozoa was conducted to include acid-fast and modified trichrome staining.ResultsFour hundred thirty-seven subjects were included in the analysis, and 75 (17.1 %) subjects were found to have enteric protozoan infections as identified by diagnostic stool microscopy. Blastocystis hominis (n = 36), Entamoeba coli (n = 25), Endolimax nana (n = 20), and Entamoeba histolytica (n = 5) were the predominant organisms isolated. Crude incidence of prior episodes of diarrhea was greater among subjects from whom enteric protozoa were isolated compared to those without (IRR 1.66, 95 % CI 1.47-1.87). Bivariate analysis of health risk and hygiene behaviors found increased odds for presence of Blastocystis hominis among those service members who reported off base ice (OR 3.61, 95 % CI 1.40-9.28) and raw vegetable consumption (OR 8.18, 95 % CI 1.40-47.5).ConclusionsThis study suggests that US service members deployed to the early stages of OIF were at greater risk of acquiring enteric protozoa than previously understood. The noted prevalence of enteric protozoa among US service members in this study is higher than in prior reports, approaching prevalence expected in the general host nation population, suggesting that US service members operating at Al-Asad Air Base in early OIF were exposed to greater degrees of fecally contaminated food and water, and poor hygienic and sanitation practices. Consumption of food and water prepared by host nation parties in Southwest Asia may place US service members at risk for acquiring intestinal protozoa.

Highlights

Infectious travelers’ diarrhea (TD) is a well-appreciated problem among service members serving abroad, where infrastructure is limited due to ongoing combat operations, and efforts at sanitation and hygiene may not be considered an immediate priority
Reports of stool samples from service members in the early stages of the most recent war in Iraq yielded pathogens typically associated with infectious diarrhea such as Shigella, enterotoxigenic E. coli (ETEC), enteroaggregative E. coli (EAEC), and norovirus
This is the only study to date that attempts to determine health risk behavior associations with the presence of enteric protozoa among deployed US service members

Summary

Introduction

Infectious travelers’ diarrhea (TD) is a well-appreciated problem among service members serving abroad, where infrastructure is limited due to ongoing combat operations, and efforts at sanitation and hygiene may not be considered an immediate priority. This study’s purpose was to identify potential risk factors for, and clinical presentations of, enteric protozoan infections in an active duty military population deployed to combat operations in the Southwest Asia. Infectious diarrhea has remained a problem for service members serving abroad for centuries, in those settings where infrastructure is still limited due to ongoing combat operations, and efforts at sanitation and hygiene may not be considered an immediate priority [1]. This study’s purpose was to identify potential risk factors for and clinical presentations of enteric protozoan infections in an active duty military population deployed to combat operations in the Southwest Asia, Iraq. An improved understanding of protozoan associations with infectious diarrhea may lead to understanding the risk, optimization of empiric therapy, and identification of potential methods for prevention

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