Reportable Medical Events (RMEs) are documented in the Disease Reporting System internet (DRSi) by health care providers and public health officials throughout the Military Health System (MHS) for monitoring, controlling, and preventing the occurrence and spread of diseases of public health interest or readiness importance. These reports are reviewed by a team of validators from Defense Centers for Public Health (DCPH). The DRSi collects reports on over 70 different RMEs, including infectious and non-infectious conditions, outbreak reports, sexually transmitted infection (STI) risk surveys, and tuberculosis contact investigation reports. A complete list of RMEs is available in the 2022 Armed Forces Reportable Medical Events Guidelines and Case Definitions.1 Data reported in these tables are considered provisional and do not represent conclusive evidence until case reports are fully validated.
Total cases among active component service members (ACSMs) reported per week are displayed in the graph for the 5 RMEs for the prior year, or preceding 52 weeks. Each quarter, the graph is updated and presented with the quarter’s (Q2, 2026) 5 most frequently reported RMEs, which may differ from previous quarters.
The DRSi requires the reporting of numerous gastrointestinal (GI) illnesses.1 In Q2 2026, the most frequently reported GI illnesses among U.S. ACSMs were norovirus, campylobacteriosis, and giardiasis. This is a change from the previous quarter, which involved a large cryptosporidiosis outbreak.
The number of reports for norovirus in DRSi were lower during April and May of 2026 than in their respective months in 2025, while the number of norovirus reports in June 2026 was slightly higher than June 2025. One norovirus outbreak report was submitted in June 2026 that included ACSMs. Additionally, campylobacteriosis and giardiasis reports in DRSi during Q2 2026 remained similar to the numbers of reports in the months of Q2 2025. One outbreak of campylobacteriosis was reported in May 2026 that affected ACSMs.
DCPH-A developed the Communicable Disease Toolkit to provide guidance for reporting RME cases and outbreaks to DRSi.2 Tools like investigation worksheets and case definition flowcharts are available in the Communicable Disease Toolkit for all RMEs, including reportable GI illnesses.
For questions about this report, please contact the Disease Epidemiology Branch at DCPH–Aberdeen. Email: dha.apg.pub-health-a.mbx.disease-epidemiologyprogram13@health.mil
References
- Armed Forces Health Surveillance Division. Armed Forces Reportable Medical Events. Accessed Aug. 26, 2026. https://health.mil/reference-center/publications/2022/11/01/armed-forces-reportable-medical-events-guidelines
- Defense Health Agency-Public Health. Communicable Disease Toolkit. Accessed Aug. 26, 2026. https://ph.health.mil/topics/healthsurv/de/Pages/cdt.aspx