Experimental tuberculosis infection of guinea pigs in the necropsy room and examination of infection risk using guinea pigs with tuberculosis

Abstract

The high incidence of tuberculosis among necropsy workers is well known and several problems related to their working conditions have been pointed out. We investigated the possibility of infection with tubercle bacilli under necropsy working conditions using guinea pigs housed in a necropsy room in which about 2,000 necropsies per year were carried out. Tuberculosis infection developed in one out of five guinea pigs. In addition, we exposed five guinea pigs to tubercle bacilli and sacrificed them in a safety cabinet. The lungs, livers, and spleens were resected, flattened, and sliced finely on a cutting board. Detection of tubercle bacilli from filtered air and the surfaces of the room was attempted, however, no bacilli were cultured. The resected tuberculous lungs were intra-tracheally treated with formalin or physiological saline and the viability of the bacilli in the lung was assessed. Bacilli survived up to two hours after physiological saline injection but no viable organisms were detected after 15 minutes of formalin treatment. These findings indicate that the necropsy room workers were exposed to tuberculosis infection. As a preventive control measure, we recommend to treat tuberculous organs in the safety cabinet and to slice lungs after formalin treatment.