Botulism from chopped garlic: delayed recognition of a major outbreak.

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.

Prevalence of hepatitis B in anaesthesia personnel.

Hepatitis B virus (HBV) infection, an occupational risk to anaesthetists, varies widely in incidence throughout the world. This study was undertaken to define the prevalence of previous HBV infection in anaesthesia personnel in the teaching hospitals of metropolitan Vancouver. Participants donated a blood sample and completed a questionnaire. Overall participation rate was 90.4 per cent. No participants were HBV carriers. Ten of 83 anaesthetists (12 per cent) had antibodies to HBV while all anaesthesia residents were seronegative. Anaesthetists with HBV antibodies tended to be either older or foreign born. Standard precautions taken by anaesthetists such as use of preoperative questioning of a patient's hepatitis status or the use of gloves when handling body fluids of a suspected or proven HBV carrier could not be shown to affect this seropositivity rate. This study, consistent with others, suggests that anaesthetists are at risk for acquiring HBV infection from occupational exposure. This risk appears to be somewhat less than that for surgeons, dentists, and staff of dialysis and urban emergency units.

Rubella-associated arthritis. I. Comparative study of joint manifestations associated with natural rubella infection and RA 27/3 rubella immunisation.

Joint manifestations observed during the course of a prospective RA 27/3 rubella immunisation trial were compared with those observed during an intercurrent wild rubella epidemic in an outlying community. Among 44 rubella haemagglutination inhibition (HAI) negative females ranging in age from 17 to 33 years who received rubella vaccine, six (13.6%) developed acute polyarticular arthritis within two to four weeks postvaccine and two (4.5%) had continuing or recurrent arthropathy lasting longer than 18 months. In contrast, among 23 females ranging in age from 11 to 39 years undergoing wild rubella infection, 12 (52.2%) developed acute polyarticular arthritis and seven (30.4%) had recurrent arthropathy 18 months postinfection. Among 23 males ranging in age from 13 to 54 years undergoing wild rubella infection, only two (8.7%) developed acute arthritis and both individuals had continuing joint manifestations 18 months postinfection. Wild rubella infection in adult populations is associated with a higher incidence, increased severity, and more prolonged duration of joint manifestations than is seen after RA 27/3 rubella immunisation.

Failed rubella immunization in adults: association with immunologic and virological abnormalities.

Immunologic and virological studies were performed in 13 adults (12 women and one man) who failed to seroconvert (as shown by rubella hemagglutination-inhibition [HAI] techniques) after single or repeated courses of HPV-77 DE/5 or RA 27/3 rubella virus vaccine. Immunologic sensitization to rubella virus was assessed from six months to eight years (mean, 3.0 years) after the last course of rubella virus vaccine by using HAI, enzyme-linked immunosorbent assay (ELISA), single radial hemolysis (SRH), neutralization, and virus-specific lymphoproliferative techniques. Despite HAI seronegativity, 11 of 13 subjects demonstrated significant sensitization to rubella virus proteins, as indicated by ELISA (10 of 13), neutralization (9 of 11), SRH (4 of 11), and rubella lymphocyte stimulation techniques (9 of 13). In addition, rubella virus was isolated from three individuals by using cocultivation techniques with peripheral blood mononuclear cells. Failed rubella immunization in adults may have more significance than previously recognized in view of altered patterns of virus-specific immunity and the association of this failure with the rubella virus carrier state.

Prospective immunological assessment of arthritis induced by rubella vaccine.

A prospective study was carried out to correlate the development of joint symptoms after rubella immunization with pre- and post-immunization rubella-specific immunological responses. Arthralgia or arthritis or both occurred in 10 of 37 adult female volunteers at a mean time of 17.0 days after immunization with the RA 27/3 rubella vaccine. All individuals studied before immunization were seronegative for rubella by either the hemagglutination inhibition or the single radial hemolysis technique. In contrast, rubella enzyme-linked immunosorbent assay or lymphoproliferative responses or both were positive in 27 of 37 (73%) individuals tested before receiving the vaccine. Rubella enzyme-linked immuno-sorbent assays carried out before immunization were positive at high levels (mean E = 0.536) in four individuals who developed recurrent episodes of arthritis after administration of the vaccine while remaining at low levels preimmunization in subjects who developed transient arthralgia (E = 0.238) or no joint manifestations at all (E = 0.288). These data provide preliminary evidence suggesting that rubella vaccine-associated arthritis may occur as a consequence of secondary, rather than primary, infection with rubella virus and that the presence of circulating, nonneutralizing rubella antibody may enhance the development or severity (or both) of the associated postinfection joint manifestations. Assessment of rubella hemagglutination inhibition, hemagglutination inhibition (immunoglobulin M), and enzyme-linked immunosorbent assay serological responses at 6 weeks and 6 months post-immunization revealed no significant differences between patients who developed and those who did not develop joint manifestations. Rubella lymphoproliferative responses were elevated at 6 weeks post-immunization in the group developing arthralgia or arthritis or both, with no difference between the groups observed at 6 months post-immunization.

Studies on vaccine-induced rubella arthritis. Serologic findings before and after immunization.

Rubella hemagglutination inhibition (HI) antibody responses were measured before and after immunization with HPV-77 DE/5 vaccine in 7 adult females with recurrent arthritis following rubella immunization and 24 hospital personnel studied prospectively while undergoing routine rubella immunization. The only distinctive serologic characteristic observed in all subjects developing rubella arthritis was a preimmunization HI titer of less than 1 : 8. No association was observed between the development of arthritis after immunization and prolongation of rubella HI IgM responses or elevation of rubella HI IgG responses.

Arbovirus infections in man in British Columbia.

During the summer of 1971, the first laboratory-proved cases of acute encephalitis in man due to any of the known arboviruses occurred in the south-central region of British Columbia. Five human cases of encephalitis with two deaths were diagnosed; three of these patients, including one of the fatalities, were proven in the laboratory to have contracted western equine encephalitis.During 1968 and 1969, a human serum survey undertaken in approximately 2000 life-long residents of the province discovered low levels of hemagglutinin-inhibiting and/or complement-fixing as well as neutralizing antibodies for western equine encephalitis, St. Louis encephalitis, Powassan encephalitis, California encephalitis and Colorado tick fever. Evidence of recent sub-clinical infection was detected in some cases.