An outbreak of appendectomies in La Désirade, Guadeloupe, August 1995-July 1996

BACKGROUND: In October 1995, over 50 cases of appendectomies among the 1.605 residents of the island La Désirade (Guadeloupe) were reported by the only island clinician to the local health authority. We describe the outbreak investigations which were implemented in order to describe the phenomenon and generate hypotheses on its cause. METHODS: An exhaustive case finding of residents having undergone appendectomy between 10 August 1995 and 22 July 1996 was conducted. We reviewed the medical charts of the cases; read pathology slides; interviewed cases and their families to retrieve detailed clinical history; studied the prevalence of markers of infection and of stool pathogens and analysed water supply quality data. RESULTS: We identified 226 cases of appendectomy (14% of the island population), 40% in May-June 1996, 46% in males and 40% under 15 years of age. Clinical, biological and pathological findings were heterogeneous and did not support the hypothesis of an outbreak of appendicitis. The study of abdominal symptoms in the families of the cases did not support person to person transmission but revealed frequent, subacute or chronic abdominal complaints. The analysis of markers of infection or of stool bacteria and parasites in a self selected sample of the island population was not suggestive. Water supply did not show any bacterial or chemical contamination. CONCLUSION: The investigation of a large outbreak of appendectomies was unable to find a single infectious or toxic origin to a high prevalence of chronic abdominal symptoms in an isolated population. An inappropriate medical answer in an isolated population probably turned heterogeneous complaints into an outbreak with major public health consequences.     

Seroepidemiological survey for influenza virus in Belém, Pará, Brazil, 1992-1993

A seroepidemiological study was carried out from 1992 to 1993 to estimate the prevalence of antibody to prevailing influenza virus strains circulating among patients attending the IEC Virology Laboratory in Belem, Northern Brazil. A total of 179 (11%) of serum samples were obtained during the post-epidemic period and processed by the hemagglutination inhibition test against the A/Taiwan/1/86 (H1N1), A/Beijing/353/89 (H3N2), and B/Yamagata/16/88 types of influenza virus. The serological results indicate circulation of viruses antigenically related to all three strains during the two-year study period. In 1992, the overall prevalence rates of HI antibodies to H1N1 and H3N2 were 84% and 56%, respectively. Presence of antibodies to both strains was detected in all age groups, suggesting intense viral activity that year. Antibodies to influenza B were detected at lower levels in all patients during this period. Similar prevalence to the H1N1 virus was noted in 1993, indicating that this strain occurred in both years. However, an increase in prevalence rates for the H3N2 virus was seen in 1993, suggesting that this strain (or a related virus) circulated intensively during this year. Influenza B activity also increased in 1993, causing infection mainly among young adults.     

Work-related mesothelioma in Québec, 1967-1990.

Prior surveys of malignant mesothelioma in Québec have noted that almost all the excess in occupational exposure related mesothelioma was in the manufacture and industrial application of asbestos rather than in the mining and milling operations. To evaluate the current status of malignant pleural mesothelioma in the Québec workforce, we reviewed all cases of pleural mesothelioma seen and accepted by the Québec Workman's Compensation Board (CSST) for work related compensation of industrial disease. We identified 120 cases, 7 of whom were females. They were of an average age of 59 +/- 8.5 yrs (sd) (range 42-84); they were exposed to asbestos dust in the workplace for an average of 26 +/- 14.3 yrs (range 0.5-50). The cases were subdivided into 3 groups according to workplace asbestos exposures. There were 49 cases originating in the mines and mills of the Québec Eastern Township region (primary industry, group 1), 50 cases from the manufacture and industrial application sector (secondary industry, group 2), and 21 cases from industries where asbestos was not a major work material, often an "incidental" material (tertiary industry, group 3). Group 1 was of an average age of 62 +/- 8 years, exposed to asbestos dust 31 +/- 14 years and the distribution of exposure time was as follows: 15% cases with < or = 10 year-exposure and 77% > or = 25 year-exposure. In group 2, the age was significantly lower at 57 +/- 9 years; the exposure time was also significantly lower at 22 +/- 14 years, and the distribution of exposure time differed from the above (29% cases with < or = 10 year-exposure and 48% > or = 25 year-exposure). In group 3, the average age was 58 +/- 7 years, the exposure time was also significantly lower at 28 +/- 12 years and the distribution of exposure time differed from the above (33% cases with < or = 10 year-exposure and 62% > or = 25 year-exposure). Analyses of the yearly incidence of new cases in each group documented the general incremental trend in all groups, with the sharpest rises in group 3. In the mining towns of Thetford and Asbestos, the incidence of mesothelioma was proportional to the workforce, thus suggesting that the tremolite air contamination, which is 7.5 x higher in Thetford, may not be a significant determinant of the disease in these workers.(ABSTRACT TRUNCATED AT 400 WORDS)