FOOD-BORNE OUTBREAK OF STREPTOCOCCAL PHARYNGITIS IN AN ISRAELI AIRFORCE BASE

A food-borne outbreak of group A beta hemolytic streptococcus (GAS) ph aryngitis occurred in an Israeli airforce base between 15 and 18 April , 1992. An epidemiologic investigation was conducted in a random sampl e of the base personnel. The effectiveness of prophylactic administrat ion of penicillin to healthy individuals during the outbreak in preven ting secondary spread of the disease was evaluated. 197 patients with pharyngitis were seen at the base clinic during the outbreak. The epid emiologic investigation indicated that the outbreak was food-borne. Co nsumption of processed white cheese that had been prepared without usi ng a proper hand washing technique, 24 h before lunch on 15 April 1992 , and subsequently kept at room temperature for 5 h, was significantly associated with GAS infection of the epidemic strain (p < 0.05), The food handler who processed the cheese had anterior cervical lymphadeno pathy and GAS T type 8/25/Imp19 (the epidemic type) was found in his t hroat culture. The secondary respiratory attack rate among the healthy base personnel (n > 1,000) was 1.6%. 40 base personnel were treated b y penicillin prophylaxis and had a secondary attack rate of 0%. The me dical personnel who were on duty during the outbreak had a secondary a ttack rate of 75% (p < 0.001). The use of penicillin prophylaxis did n ot have an advantage in preventing secondary respiratory spread of str eptococcal pharyngitis. Penicillin prophylaxis might reduce the high s econdary attack rate of the disease in risk groups such as the medical personnel.