A military medical surveillance system that collects, analyzes, and disseminates health information facilitates DOD’s ability to intervene in a timely manner to address health care problems experienced by military personnel. DOD believes such a system is one of the principal means to ensure a fit and healthy force and to prevent disease and injuries from degrading warfighting capabilities. Based on our review of the Presidential Advisory Committee and the Institute of Medicine reports and discussions with DOD officials, for the purposes of this report we identified four major elements of a military medical surveillance system, as shown in table 1. The Presidential Advisory Committee and the Institute of Medicine investigations into the causes of illnesses experienced by Gulf War veterans confirmed the need for effective medical surveillance capabilities. Research efforts to determine the causes of what has become known as veterans’ Gulf War illnesses have been hampered due to incomplete medical surveillance data on (1) the names and locations of personnel deployed to the Persian Gulf, (2) exposure of personnel to environmental health hazards, (3) changes in the health status of personnel deployed in the theater, and (4) records of immunizations and other health services provided to the individuals while deployed. In essence, the data available were poorly suited to support epidemiologicaland health outcome studies related to veterans’ Gulf War illnesses. For over 2 years, DOD officials have been working to develop a DOD-wide joint medical surveillance directive and instruction that establish policy and assign responsibility for improving DOD’s medical surveillance for deployments. The intent of the policy is to expand the concept of medical surveillance during deployments to a more comprehensive approach for monitoring and assessing the health consequences related to servicemembers’ participation in deployments. We reviewed this draft policy and found that it addresses the types of medical surveillance problems experienced during the Gulf War—the lack of personnel deployment information and medical assessments, the failure to monitor environmental and disease health threats, and the failure to meet record-keeping requirements. Specifically, the draft policy instruction assigns responsibilities as follows: Assigns to the Defense Manpower Data Center (DMDC) the responsibility for collecting and maintaining information, available for dissemination on a daily basis, on each servicemember deployed to a theater, the length of time the servicemember was deployed, and the exact location within the theater of that member’s unit. Specifies that the Commander in Chief (CINC) and the Joint Task Force (JTF) Surgeon deploy technically specialized units with the capability and expertise required to identify infectious and environmental diseases, make health hazard assessments, and do advanced diagnostic testing. Requires the military services and the CINCs to conduct predeployment medical assessments, to include assessing mental health and drawing blood samples. Requires the CINC Surgeon and the JTF Surgeon to conduct postdeployment medical assessments at the time of redeployment or within 30 days of final departure, to include assessing mental health and drawing blood samples. For both the predeployment and the postdeployment medical assessments, the policy calls for the assessment forms to be forwarded to a single office within DOD for centralized collection purposes and to allow future analyses. Directs the CINC Surgeon and the JTF Surgeon to ensure that medical records are accurately kept and health-related events are documented during deployment. Specifically suggested are records of predeployment and postdeployment assessments and all health interventions (which would include all immunizations). The draft directive and implementing instruction are currently under review by various offices within DOD. DOD officials expect the directive and instruction to be issued by September 1997. The responsible offices are required to develop the necessary implementing documents within 180 days of the directive’s effective date. While DOD was still developing its joint medical surveillance policy for deployments, the Assistant Secretary of Defense for Health Affairs issued, in January 1996, a medical surveillance plan for U.S. forces deploying to Bosnia-Herzegovina, Croatia, and Hungary under Operation Joint Endeavor. This medical surveillance plan encompassed the concepts under consideration in the draft joint policy, was developed by a triservice working group, and was coordinated by the Joint Staff with the services. It was designed to reflect the lessons learned from the Gulf War and to address the potential health risks in the Bosnian theater. According to DOD officials, this DOD-wide, centrally managed medical surveillance plan was the first DOD had developed for a deployment of U.S. forces. The strategy for implementing the plan was determined by the service Surgeons General, the Joint Staff, and the European Command Surgeon. Using the four major elements of a military medical surveillance system described earlier, we examined DOD’s and the services’ implementation of the Operation Joint Endeavor medical surveillance plan. The ability to identify the population at risk is an essential part of an effective military medical surveillance system. It is important to know which servicemembers deployed to the theater and where they were located within the theater during the deployment. This information is needed to facilitate monitoring and analysis of how changes in the servicemembers’ health status is related to various environmental, biological, chemical, or other health threats. Our review indicated that DOD continues to experience problems with its capability to track the population at risk during deployments. In researching the Persian Gulf War illnesses, the Institute of Medicine and the Presidential Advisory Committee reported that inaccurate information on the location of servicemembers in the theater presented problems in identifying exposures to various health threats. Both recommended that DOD improve its ability to track the location of units in the theater. DOD established systems to identify the location of units during the Gulf War; however, the research groups reported that their use for epidemiological studies was limited because the systems did not provide information at the individual servicemember level. During the Gulf War, servicemembers frequently did not remain with their units. DOD established a system, used in Operation Joint Endeavor, to identify which servicemembers deployed to the theater. The services are required to supply deployment data to the DMDC in Monterey, California, which is responsible for maintaining a database on those servicemembers who are deployed. In determining the extent to which the services had done the required postdeployment medical assessments, we used the Army’s deployment data and did not find any errors about which servicemembers had deployed. However, DOD officials expressed their concerns about the accuracy of the deployment database for Air Force and Navy personnel. Air Force officials told us that the Air Force had supplied information to DMDC on servicemembers it planned to deploy. These servicemembers were added to the DMDC database, but many never actually deployed. We were also told that the Navy’s personnel deployment data were inaccurate because elements of two construction battalions (at least 200 servicemembers) that deployed to Operation Joint Endeavor do not appear in the DMDC database. DOD officials told us that they have also frequently heard concerns about the accuracy of the deployment database and met in mid-March 1997 with representatives from the services, DMDC, and other offices to discuss ways to correct the problems. While the DMDC database provides information on which units and which personnel within those units deploy to a theater, DOD has not yet developed a system for accurately tracking the movement of individual servicemembers in units within the theater. This capability is important for accurately identifying exposures of servicemembers to health hazards in the theater. A military medical surveillance program should contain mechanisms for identifying the potential health and environmental hazards that deploying troops will encounter in the theater. Such information can then be used to develop effective preventive countermeasures and identify those exposed to these threats. During the Gulf War, DOD did little prospective monitoring of environmental health threats in the theater and had no systematic means of tracking and centrally reporting the occurrence of diseases and nonbattle injuries during the war. In its 1996 report, the Institute of Medicine recommended that, in preparing for deployments, DOD should monitor the environment for possible health threats and prepare for rapid response and investigation and collect accurate data on exposures to those threats in the theater of operations. Prior to deployments, DOD identifies diseases/illnesses common to the environment in the theater and informs medical personnel and deploying troops on ways to avoid or protect themselves from these diseases/illnesses. According to DOD officials, a predeployment assessment of potential health hazards in the Operation Joint Endeavor theater indicated that diseases such as tick-borne encephalitis, hemorrhagic fever, typhus, and lyme disease could be problems. A tick-borne encephalitis vaccine was offered to those military personnel who might be in danger of contracting the disease because of their proximity to ticks. In addition, troops were advised on ways to best protect themselves from the other diseases, and medical personnel were instructed to be particularly alert for symptoms that might indicate that a servicemember had one of the diseases/conditions. Of the potential diseases/illnesses identified, only one case of hemorrhagic fever was diagnosed, and the patient was successfully treated. The establishment in 1994 of the U.S. Army Center for Health Promotion and Preventive Medicine (USACHPPM) has been a major enhancement to DOD’s ability to perform environmental monitoring and tracking since the Gulf War. This capability was augmented in October 1995 with the establishment of the 520th Theater Army Medical Laboratory. This laboratory is a deployable public health laboratory that can provide environmental sampling and analysis in theater. The sampling results can then be used to determine what specific preventive measures and safeguards should be taken to protect troops from harmful exposures and to develop procedures to treat anyone exposed to health hazards. Early in the planning for Operation Joint Endeavor, the Armed Forces Medical Intelligence Center identified potential environmental health threats in Bosnia-Herzegovina as coming primarily from exposures to air, water, and soils contaminated by hazardous industrial waste.