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Foodborne botulism from home-canned bamboo shoots Thailand, 1998. Wongwatcharapaiboon P Sriprasert P Leksririvili S . Thaikruea L Nanthavas S Thanawong A. Thai FETP. Acknowledgements. Nan Provincial Health Office and Hospital National Institute of Health - PowerPoint PPT Presentation
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Foodborne botulism from home-canned bamboo shoots
Thailand, 1998
• Wongwatcharapaiboon P • Sriprasert P • Leksririvili S
• Thaikruea L• Nanthavas S • Thanawong A
Thai FETP
Acknowledgements• Nan Provincial Health Office and Hospital
• National Institute of Health
• Armed Force Research Institute of Medical Science
• US Army Medical Research Institute for infectious
Disease
Thai FETP
Objective• Confirm and describe the outbreak
• Verify diagnosis
• Identify the source
• Develop control and prevention strategies
Thai FETP
To
Methodology• Reviewed medical records
• Interviewed patients in the hospital
• Performed– Active case finding
– Case-control study
– Laboratory investigation
– Environmental survey
Thai FETP
Case definition• Resident of village A or B • At least 3 symptoms between April 8 -
17, 1998– Ptosis - Dysphagia– Dysarthria - Dysphonia– Dry mouth - Sore throat– Diarrhea - Vomiting– Symmetrical flaccid paralysis
Thai FETP
Descriptive results • 13 cases with 2 deaths (CFR 15%)
– 12 (92%) lived in village A
– 9 (69%) were hospitalized
– 9 (69%) were female
– Median age 44 years (range: 38-68)
Thai FETP
Clinical manifestations (N=13)
23%
31%
31%
38%
54%
54%
62%
85%
0% 20% 40% 60% 80% 100%
Ptosis
Paralysis
Dysarthria
Diarrhea
Dysphonia
Vomiting
Dry mouth
Dysphagia
Thai FETP
Epidemic curve Villages A and B, April, 8-17, 1998 (n= 12)
01234567
8 9 10 11 12 13 14 15 16 17
No.cases
April 1998
Date of onsetThai FETP
01234567
8 9 10 11 12 13 14 15 16 17
Epidemic curve Villages A and B, April, 8-17, 1998 (n= 12)No.c
ases Ate breakfast together, April 10
April 1998
Date of onsetThai FETP
Family XFamily Y
Food history of cases (N=13)
Food Number ofcases
Attack rate%
Home-cannedbamboo shoot
13 100
Distilled alcoholicbeverage
6 46
Undistilled alcoholicbeverage
8 62
Mushroom 3 23
Thai FETP
Case-control study
• Control definition–Person who participated in cremation
of 2 dead cases
Thai FETP
Case-control study
• 66 controls,
• All were female
• 28 lived in village A
Thai FETP
Case-control studyHome-cannedbamboo shoots
case control
ate 13 4
not ate 0 62
OR = undetermined
Thai FETP
Case control study Suspected Foods OR 95% CI
Home-cannedbamboo shoots
undetermined
-
Distilled alcoholicbeverage
8.57 2.2 - 33.9
Undistilled alcoholicbeverage
2.62 0.8 - 8.9
Mushroom 0.94 0.2 - 3.8
Thai FETP
Case-control studyHeated
Home-cannedbamboo shoots
case control
ate 1 3
not ate 12 1
OR = 0.03 (95 % CI = 0.00 -0.95)
Thai FETP
Laboratory result
• EMG of 2 cases - consistent with botulism
• Stool culture -negative C. botulinum
• Home-canned bamboo shoots
– negative culture
– positive botulinum toxin type A by ELISA and
mouse antitoxin bioassay
Thai FETP
Laboratory result
• Soil samples from houses
surrounding that of the home- canned
bamboo shoots manufacturer
– negative for C. botulinum
Thai FETP
Botulism• Caused by toxin of anaerobic bacteria
• Outbreak usually due to home- canned
low acid foods ( pH < 4.5)
• Toxin is heat labile (100 oC, 10 min)
• Spores are destroyed in 120 oC, 30 min
Thai FETP
Interventions• Prohibited sale of remaining 650 cans
• Extended loans
• Educated people to heat bamboo shoots
• Enforced high temperature processing
• Strengthened surveillanceThai FETP
Discussion• Confirmed botulism outbreak• Common source
–Home-canned bamboo shoots
• Improper process– Low acid– 100 oC
• Aware of other home-canned foodsThai FETP
Limitation
• Selection of controls – only women
• Sample not collected under strictly anaerobic condition
Thai FETP
Recommendation• Quality control of home-canned food
• Clinical and laboratory surveillance
– Case and Toxin detection
• Antitoxin should be available
Thai FETP
Thank youfor your kind
attentionThai FETP
Why did it not occur in the past? • Culture of Thai people ate fresh foods • Home canning was promoted in only past 2 years• Screening abnormal can
– Air detection by percussion– Abnormal smell or taste
• Depend on chance – To find spores in soils– To wash bamboo shoots incompletely
Result of EMG• Normal nerve conduction velocities
• Low amplitude response to single stimulus
• Decremental trend in amplitude to repetitive low-frequency stimulation (2-5 Hz)
• Incremental (facilitation) trend to rapid repetitive stimulation (20-50 Hz)
Thai FETP