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.
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[Show abstract][Hide abstract] ABSTRACT: Northern Thailand's biggest botulism outbreak to date occurred on 14 March 2006 and affected 209 people. Of these, 42 developed respiratory failure, and 25 of those who developed respiratory failure were referred to 9 high facility hospitals for treatment of severe respiratory failure and autonomic nervous system involvement. Among these patients, we aimed to assess the relationship between the rate of ventilator dependence and the occurrence of treatment by day 4 versus day 6 after exposure to bamboo shoots (the source of the botulism outbreak), as well as the relationship between ventilator dependence and negative inspiratory pressure.
We reviewed the circumstances and timing of symptoms following exposure. Mobile teams treated patients with botulinum antitoxin on day 4 or day 6 after exposure in Nan Hospital (Nan, Thailand). Eighteen patients (in 7 high facility hospitals) with severe respiratory failure received a low- and high-rate repetitive nerve stimulation test, and negative inspiratory pressure was measured.
Within 1-65 h after exposure, 18 of the patients with severe respiratory failure had become ill. The typical clinical sequence was abdominal pain, nausea and/or vomiting, diarrhea, dysphagia and/or dysarthria, ptosis, diplopia, generalized weakness, urinary retention, and respiratory failure. Most patients exhibited fluctuating pulse and blood pressure. Repetitive nerve stimulation test showed no response in the most severe stage. In the moderately severe stage, there was a low-amplitude compound muscle action potential with a low-rate incremented/high-rate decremented response. In the early recovery phase, there was a low-amplitude compound muscle action potential with low- and high-rate incremented response. In the ventilator-weaning stage, there was a normal-amplitude compound muscle action potential. Negative inspiratory pressure variation among 14 patients undergoing weaning from mechanical ventilation was observed. Kaplan-Meier survival analysis identified a shorter period of ventilator dependency among patients receiving botulinum antitoxin on day 4 (P=.02).
Patients receiving botulinum antitoxin on day 4 had decreased ventilator dependency. In addition, for patients with foodborne botulism, an effective referral system and team of specialists are needed.
[Show abstract][Hide abstract] ABSTRACT: We conducted a clinical study of 137 patients with home-canned bamboo shoot botulism at Nan Hospital, northern Thailand. The median age of the patients was 44 years (range = 14-74 years) and 36.2% were male. The median incubation period was 2 days (range = 1-8 days). Forty-three patients (31.4%) developed respiratory failure, but there were no deaths. Patients who did not have either nausea or vomiting and did not have urinary retention that required Foley catheterization was less likely to develop respiratory failure. This clinical predictor rule had a sensitivity of 75.5% and a specificity of 90.7%. The clinical syndrome most predictive of respiratory failure was nausea or vomiting and any cranial neuropathy with urinary retention or difficulty swallowing. This clinical syndrome had a sensitivity of 69.8% and a specificity of 93.6%. These clinical characteristics could help triage large numbers of patient in the event of a future outbreak.
The American journal of tropical medicine and hygiene 09/2007; 77(2):386-9. · 2.70 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this study we describe the electrophysiological findings in botulism patients with neuromuscular respiratory failure from major botulism outbreaks in Thailand. High-rate repetitive nerve stimulation testing (RNST) of the abductor digiti minimi (ADM) muscle of 17 botulism patients with neuromuscular respiratory failure showed mostly incremental responses, especially in response to >20-HZ stimulation. In the most severe stage of neuromuscular respiratory failure, RNST failed to elicit a compound muscle action potential (CMAP) of the ADM muscle. In the moderately severe stage, the initial CMAPs were of very low amplitude, and a 3-HZ RNST elicited incremental or decremental responses. A 10-HZ RNST elicited mainly decremental responses. In the early recovery stage, the initial CMAP amplitudes of the ADM muscle improved, with initially low amplitudes and an incremental response to 3- and 10-HZ RNSTs. Improved electrophysiological patterns of the ADM muscle correlated with improved respiratory muscle function. Incremental responses to 20-HZ RNST were most useful for diagnosis. The initial electrodiagnostic sign of recovery following treatment of neuromuscular respiratory failure was an increased CMAP amplitude and an incremental response to 10-20-HZ RNST. Muscle Nerve 40: 271-278, 2009.