A tuberculosis event on a Navy assault ship.

ABSTRACT

A tuberculosis event occurred on a U.S. Navy amphibious assault ship in September 2003. The event was signaled by a jump in monthly purified protein derivative positivity rates. A baseline new reactor rate of 0 to 1% suddenly jumped to 6.3%, prompting screening of the entire crew and embarked Marines. Ultimately, a total of 31 Navy and 17 Marine new reactors was identified. This represented 2.4% of the Navy crew and 1.2% of embarked Marines. Only 1 of 31 Navy cases involved an officer. Two Navy, male, enlisted berthing areas showed a statistically significantly increased odds ratio for infection risk. Despite intensive investigation, no active case of tuberculosis was ever identified. After treatment of new reactors with isoniazid, the ship's monthly new reactor rate returned to baseline. This case illustrates the principles and pitfalls of respiratory disease control at sea.