NHRC Population-Based Surveillance Among U.S. Military Recruits

The Enteric Disease Surveillance Program (EDSP), part of the Naval Health Research Center (NHRC) Operational Infectious Diseases Department, is focused on describing the epidemiology of enteric diseases among at-risk U.S. military populations, including recruits and operational forces. The program establishes acute gastroenteritis (AGE) surveillance with the specific goals of quantifying disease burden and operational impact, developing a diagnostics platform, and evaluating therapeutic and prophylactic products to limit the impact of gastroenteritis on U.S. forces afloat and ashore. 

Enteric diseases are the most commonly reported health care issues among troops; one of the most debilitating is AGE. AGE is the rapid onset of diarrheal disease with or without accompanying symptoms (nausea, vomiting, fever or abdominal pain). AGE is commonly reported among deployed military populations, and studies show that most cases are likely caused by norovirus (NoV), which causes approximately 90 percent of reported nonbacterial AGE outbreaks in Western countries. NoVs are highly contagious and are transmitted via ingestion of contaminated food and drink as well as person-to-person via aerosols. 

EDSP’s initial focus was to describe the etiology and epidemiology of AGE among military recruits at Marine Corps Recruit Depot (MCRD) San Diego, MCRD Parris Island, and Recruit Training Command Great Lakes. Surveillance was designed as clinic-based, where researchers enrolled, collected and conducted laboratory testing on specimens from recruits seeking medical care for AGE. Researchers also tested clinical specimens collected from personnel deployed on USNS COMFORT (T-AH20) during Operation Continuing Promise 2011 and specimens collected during a large AGE outbreak at the U.S. Air Force Academy in Colorado Springs, Colo., in 2011. 

Through February 2012, EDSP enrolled 239 AGE cases. In 38 percent of the cases, an enteric pathogen was identified. NoV was the most common, present in 32 percent of the cases. Overall, a total of 16 Salmonella strains were isolated from study participants, 11 from MCRD San Diego and 5 from MCRD Parris Island. 

Of special note, from November to December 2011, EDSP, in collaboration with San Diego County Public Health and the California State Laboratory, identified and typed 10 Salmonella cases, defining a unique cluster of cases among recruits stationed only at MCRD San Diego. 

These cases prompted the Naval Medical Center San Diego Preventive Medicine Department to conduct inspections, leading to modifications in berthing and kitchen areas to control further spread. 

AGE significantly impacts military personnel, and NoV is a primary etiological agent. NoV is an important health threat to the Department of Defense, and it affects both deployed ground and shipboard populations and recruits. 

NHRC also works closely with operational units by conducting medical modeling and simulation analysis, monitoring the effects of combat exposure on psychological health, managing career-span deployment health and readiness programs, improving warfighter performance and assisting in the implementation of military-specific HIV prevention programs around the world. 

Article provided courtesy of Naval Medical Research & Development News. Author credit: Dr. Shan Putnam and Dr. Ramona McCaffrey, NHRC Enteric Disease Research Surveillance Program.