An outbreak of type A viral hepatitis at the Naval Training Center, San Diego: epidemiologic evaluation.

In October 1974, a large foodborne outbreak of hepatitis occurred among naval personnel undergoing basic training at the Naval Training Center, San Diego, California. Of the 2781 recruits eating at the implicated dining hall on the day disease transmission occurred, 133 developed clinical or laboratory evidence of hepatitis for an attack rate of 47.8/1000. The epidemiologic investigation suggested that hepatitis A virus was the etiologic agent, and this was subsequently confirmed by laboratory examination. The index and source case was a recuit food-handler who experienced prodromal symptoms of hepatitis while preparing salads and fresh fruit 32 days prior to the outbreak. A food preference questionnaire implicated tossed salad and fresh grapefruit as the specific vehicles of transmission.