title: Botulism from chopped garlic: delayed recognition of a major outbreak.
abstract: Diagnosis of botulism in two teenaged sisters in Montreal led to the identification of 36 previously unrecognized cases of type B botulism in persons who had eaten at a restaurant in Vancouver, British Columbia, during the preceding 6 weeks. A case-control study implicated a new vehicle for botulism, commercial chopped garlic in soybean oil (P less than 10(-4)). Relatively mild and slowly progressive illness, dispersion of patients over at least eight provinces and states in three countries, and a previously unsuspected vehicle had contributed to prolonged misdiagnoses, including myasthenia gravis (six patients), psychiatric disorders (four), stroke (three), and others. Ethnic background influenced severity of illness: 60% of Chinese patients but only 4% of others needed mechanical ventilation (P less than 10(-3]. Trypsinization of serum was needed to show toxemia in one patient. Electromyography results with high-frequency repetitive stimulation corroborated the diagnosis of botulism up to 2 months after onset. Although botulism is a life-threatening disease, misdiagnosis may be common and large outbreaks can escape recognition completely.
authors.affiliation: Enteric Diseases Branch, Centers for Disease Control, Atlanta, Georgia.
authors.forename: M E
authors.initials: ME
authors.lastname: St Louis
authors.forename: S H
authors.initials: SH
authors.lastname: Peck
authors.forename: D
authors.initials: D
authors.lastname: Bowering
authors.forename: G B
authors.initials: GB
authors.lastname: Morgan
authors.forename: J
authors.initials: J
authors.lastname: Blatherwick
authors.forename: S
authors.initials: S
authors.lastname: Banerjee
authors.forename: G D
authors.initials: GD
authors.lastname: Kettyls
authors.forename: W A
authors.initials: WA
authors.lastname: Black
authors.forename: M E
authors.initials: ME
authors.lastname: Milling
authors.forename: A H
authors.initials: AH
authors.lastname: Hauschild
mesh_terms: D001905:Botulinum Toxins / Q000097:blood; D001906:Botulism / Q000150:complications / Q000453:epidemiology / Q000208:ethnology / Q000209:etiology*; D001955:British Columbia; D002681:China / Q000208:ethnology; D004196:Disease Outbreaks; D005511:Food Handling; D005737:Garlic / Q000009:adverse effects*; D006801:Humans; D009422:Nervous System Diseases / Q000209:etiology; D010946:Plants, Medicinal; D012131:Respiratory Insufficiency / Q000209:etiology; D012147:Restaurants; D013029:Space-Time Clustering; D013696:Temperature
chemical_list: D001905:Botulinum Toxins