Outbreak of tropical rat mite dermatitis in laboratory personnel.

An outbreak of tropical rate mite (Ornithonyssus bacoti) dermatitis occurred in a group of research and animal technicians. The technicians were affected with an intense pruritic dermatitis after exposure to asymptomatic laboratory mice infested with the mite. Locating the resident host of the mite is critical in the successful elimination of the mite from the premises and in preventing further contact with and irritation to human occupants.