Skip main navigation

Military Health System

Clear Your Cache

Health.mil has undergone a recent update. For the best user experience we recommend clearing your browser cache.

Marines with combined anti-armor team conduct weapon familiarization training June 3 at the North Training Area at Combined Arms Training Center Camp Fuji. It was the first time for many of the Marines to fire the AT-4 light anti-armor weapon. The Marines are with the CAAT of Weapons Company, 3rd Battalion, 6th Marine Regiment, which is currently assigned to 4th Marine Regiment, 3rd Marine Division, III Marine Expeditionary Force, under the unit deployment program. The combat correspondent captured the photo at a shutter speed of 1/160th of a second, creating a multiple-exposure effect of the AT-4 gunner, as well as capturing the dust being shaken from the Marines’ helmets as a result of the shockwave created from the concussion of the weapon’s back-blast. (U.S. Marine Corps photo by Cpl. Adam B. Miller/Released)
Need larger text?
Skip subpage navigation

Anomalous Health Incidents

The Department of Defense and Defense Health Agency are committed to preventing, treatment, and recovering patients who report symptoms of an Anomalous Health Incident. DHA is actively developing a standard care pathway for both DOD and non-DOD beneficiaries to receive appropriate medical care as quickly as possible. To support this, patient resources have been developed to provide information on how to seek medical attention within the Military Health System and an overview of medical care coverage. Additionally, multiple provider resources are available to support care management and ensure proper documentation of treatment. This site will continue to be updated with products, trainings, and resources as they become available.

Overview and Symptoms

Previously referred to as Havanna Syndrome or as an Unconventional Brain Injury, AHI is the term used to describe a group of sudden symptoms that occur after an unexplained sensory event or events that are not associated with a history of head trauma. AHI events have been reported by several DOD and Federal Agency personnel since 2016.

Possible symptoms that are associated with an AHI event may include but are not limited to:

  • Auditory Symptoms
  • Balance Problems 
  • Cognitive complaints 
  • Difficulty concentrating
  • Head Pressure
  • Headache
  • Hearing Changes
  • Memory Problems 
  • Nausea
  • Dizziness

You also may be interested in...

Last Updated: March 19, 2025
Follow us on Instagram Follow us on LinkedIn Follow us on Facebook Follow us on X Follow us on YouTube Subscribe to updates from the MHS