Foodborne botulism outbreaks following consumption of home-canned bamboo shoots in Northern Thailand.

We report epidemiological investigations of 2 outbreaks of foodborne botulism following consumption of home-canned bamboo shoots in northern Thailand. The first outbreak affecting 4 female and 2 male cases occurred in Mae Sot District, Tak Province, in December 1997. All 6 cases were hospitalized, 4 of whom required mechanical ventilation. All cases experienced neurological features and 4 had gastrointestinal symptoms. One case died, giving a case-fatality rate of 16.7 per cent. A case-control study revealed a significant association (p < 0.01) between the disease and consumption of home-canned bamboo shoots purchased from the same foodshop in the village. The second outbreak of a similar clinical syndrome occurred in Thawangpha District, Nan Province, in April 1998. A total of 13 cases were identified, 9 (69.2%) of whom were female. Nine cases (69.2%) were hospitalized, 4 (30.8%) of whom required mechanical ventilation. Two early hospitalized cases died due to ventilatory failure, giving a case-fatality rate of 15.4 per cent. A case-control study indicated that home-canned bamboo shoots prepared by a local foodshop served as the vehicle for the disease transmission. One bamboo shoot specimen from one affected house was positive for botulinum toxin type A by enzyme-linked immunosorbent assay and mouse antitoxin bioassay. Improper home-canning procedures for bamboo shoot preservation were similarly detected in both outbreaks although performed by different merchants. Prompt recognition and treatment of the disease are essential in reducing the fatality rate. Safe home-canning procedures should be widely distributed and instructed to persons who perform bamboo shoot preservation for sale.

A report of an outbreak of postoperative endophthalmitis.

We report an outbreak of endophthalmitis following cataract extraction or secondary intraocular lens (IOL) implantation in a 400-bed general hospital in northern Thailand. From December 1997 to September 1998, of 329 patients who had undergone cataract extraction or secondary IOL implantation in the hospital, 31 (9.4%) developed postoperative endophthalmitis. The interval between the operation and the clinical diagnosis of endophthalmitis ranged from 5 to 74 days with a median of 15 days. Of the 31 cases of endophthalmitis, 18 occurred in phacoemulsification (PE) with IOL, 11 in extracapsular cataract extraction (ECCE) with IOL, and 2 in secondary IOL implantation. Patients who had undergone PE with IOL had a significantly higher rate (12.4%) than those of ECCE with IOL (6.3%). The infection rates also increased with the order of the operations within each operation period (morning or afternoon); later operations were at higher risk. Our findings detected defects in sterilization for the surgeries including possible inadequacy in the autoclave sterilization of surgical instruments, insufficient exposure time with 2 per cent activated glutaraldehyde solution (about 15-30 minutes) for sterilizing some surgical instruments, and the use of multiple-dose intraocular irrigating solution. This outbreak of endophthalmitis emphasizes the necessity to monitor regularly the practice of sterilization/disinfection in hospitals for prevention and control of nosocomial infections.