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A serologically confirmed, case-control study, of a large outbreak of hepatitis a in China, associated with consumption of clams

Published online by Cambridge University Press:  15 May 2009

Y. W. Tang*
Affiliation:
Department of Epidemiology, Shanghai, 200032, People's Republic of China
J. X. Wang
Affiliation:
Department of Epidemiology, Shanghai, 200032, People's Republic of China
Z. Y. Xu
Affiliation:
Department of Epidemiology, Shanghai, 200032, People's Republic of China
Y. F. Guo
Affiliation:
Department of Sanitary Microbiology, School of Public Health, Shanghai Medical University, Shanghai, 200032, People's Republic of China
W. H. Qian
Affiliation:
Anti-Epidemic and Health Station of Changning District, Shanghai, 200032, People's Republic of China
J. X. Xu
Affiliation:
Anti-Epidemic and Health Station of Changning District, Shanghai, 200032, People's Republic of China
*
*Dr Yi Wei Tang. Division of Infectious Diseases. Department of Medicine. Vanderbilt University Medical Center. A3310 MCX. Nashville. TN 37232-2605. USA.
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A matched and serologically confirmed case-control study was carried out to investigate the source of an outbreak of acute hepatitis involving 290000 cases in the suburbs of Shanghai, in January 1988. A total of 132 patients with acute hepatitis from six different hospitals were chosen as cases and the same number of control patients without hepatitis were matched for gender, age, admission date and area of residence. Serum specimens from both case and control patients were detected for specific anti-hepatitis A (HA) IgM antibody and a questionnaire was used to investigate probable risk factors related to the outbreak. The positive rate of anti-HA IgM was 98·48% in the case group and only 0·76% in the control, indicating that the infection was caused by HA virus. The results revealed that the source and mode of transmission were due to the consumption of contaminated and inadequately cooked clams (Anadara subcrenata lischke). There was a highly positive dose-response relationship between the odds ratio of contracting HA and the quantity or frequency of clam consumption. The odds ratios of acquiring HA from clams were up to 62·4–63·4 by both group stratification and multiple unconditional logistic regression analyses.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1991

References

REFERENCES

1Kang, LY, Liu, GY, Hu, SL. An investigation of an epidemic outbreak of hepatitis A. Chinese J Infect Dis 1983; 1: 168–72.Google Scholar
2Qiu, HS. Epidemiologic investigation of an outbreak of hepatitis A due to contaminated blood clams. Chinese J Prev Med 1979; 13: 229–32.Google ScholarPubMed
3Deinhardt, FW. Significance of anti-HAV of the IgM class for the diagnosis of hepatitis A. In Viral hepatitis, ed. Vyas, GN. Philadelphia: Franklin Institute Press. 1978: 736–41.Google Scholar
4Xu, ZY. Detection of specific anti-hepatitis A antibody by using an IgM-capture enzyme linked immunosorbent assay. Shanghai Med J 1982; 5: 406–10.Google Scholar
5Yu, SL, Dai, XD. Application of conditional logistic regression model in the matched case-control study. Chinese J Prev Med 1985; 19: 292–6.Google Scholar
6Miettinen, O. Estimability and estimation in case referent studies. Amer J Epidemiol 1976; 103: 226–34.CrossRefGoogle ScholarPubMed
7McGee, DL. Epidemiologic programs for computers and calculators. A program for logistic regression on the IBM PC. Amer J Epidemiol 1986; 124: 702–9.Google Scholar
8Wang, JX, Xu, ZY. Detection of hepatitis A virus from clinical specimens by cDNA-RNA hybridization. Acta Acad Med Shanghai 1988; 15: 380–3.Google Scholar
9Mosley, JW, Galambos, JT. Viral hepatitis. In Diseases of the liver. Schiff, L. ed. Philadelphia: J B Lippincott. 1975: 500–93.Google Scholar
10Goh, KT, Chen, L, Ding, JL, Oon, CJ. An epidemic of cockles-associated hepatitis A in Singapore. Bull WHO 1984; 62: 893901.Google Scholar
11Ruddy, SJ, Jahnson, RF, Mosley, JW, Atwater, JB, Rossetti, MA, Hart, JC. An epidemic of clam-associated hepatitis. JAMA 1969; 208: 649–61.CrossRefGoogle ScholarPubMed
12Mele, A, Rastelli, MG, Gill, ON, et al. Recurrent epidemic hepatitis A associated with consumption of raw shellfish, probably controlled through public health measures. Amer J Epidemiol 1989; 130: 540–6.Google Scholar
13Mitchell, JR, Presnall, MW, Atkin, EW, Cummins, JM, Liu, OC. Accumulation and elimination of poliovirus by the eastern oyster. Amer J Epidemiol 1966; 84: 4050.CrossRefGoogle ScholarPubMed
14Koff, RS, Sear, HS. Internal temperature of steamed clams. New Engl J Med 1967; 276: 737–9.CrossRefGoogle ScholarPubMed
15Millord, J, Appleton, H, Parry, JV. Studies on heat inactivation of hepatitis A with special reference to shellfish. Epidemiol Infect 1987; 98: 397414.CrossRefGoogle Scholar