Enterohaemorrhagic Escherichia Coli Infection in Radish Sprouts in Japan

Enterohaemorrhagic Escherichia coli Infection 

Food Safety

Weekly Epidemiological Record, No. 35, 30 AUGUST

World Health Organization, Geneva1996, 71, 261-268

Japan. Updated information has been obtained on the outbreak of enterohaemorrhagic Escherichia coli (EHEC) infection in Sakai City in July 1996.1 The outbreak has affected a total of 6 309 schoolchildren and 92 school staff members from 62 municipal elementary schools. Another 160 people, mainly family members of infected schoolchildren, have contracted secondary infections. Since 8 August, no new cases have been reported. The number of hospitalized patients peaked at 534 on 18 July and had decreased to 31 by 26 August. The number of patients suffering from haemolytic uraemic syndrome (HUS) peaked at 101 on 24 July. Two, a 10-year-old girl and a 12-year-old girl, had died by 26 August. E. coli serotype O157:H7 was commonly detected in patients stool samples. 

The epidemiological investigation has revealed that fresh radish sprouts (kaiware-daikon) were among the foods eaten in common by the schoolchildren. Radish sprouts, which are popularly eaten raw in Japan, were served in school lunches either on 8 or 9 July, depending on the school. In another outbreak which occurred also in July 1996 in a home for the elderly in Habikino City (98 people affected) as well as in 3 other small outbreaks in the nearby region, the radish sprouts produced by the same farm have been identified to have also been consumed. The DNA patterns ofE. coli, analysed by the National Institute of Health, Japan, were identical among the isolates from the 5 outbreaks. However, samples of radish seeds and sprouts, water and soil from the environment of the farm concerned and stool samples from the farm workers showed no trace of this organism. 

As of 26 August 1996, a total of 9 578 cases of E. coli serotypes O157:H7 and O157:H- infection, including both outbreaks and sporadic infections, had been reported in Japan this year, resulting in 11 deaths. Although most of the cases are believed to be foodborne, the responsible foods have not been identified with certainty except for a few isolated cases. The analysis of DNA patterns of the isolates from various sources suggests a heterogenous originof contamination. A report on the outbreaks of EHEC infection is available in the Infectious Agents Surveillance Report (IASR)2 from the National Institute of Health, Japan. The Government of Japan is continuing its investigation and has been putting in place a number of preventive measures, with emphasis on guidance and verification to ensure hygienic practice in mass catering facilities in schools as well as other food-handling establishments. 

(Based on: Reports from the Ministry of Health and Welfare, Tokyo.) 

Editorial Note: General information about EHEC is available in a WHO Fact Sheet on Escherichia coli O157:H7 (Fact Sheet No. 125, July 1996). 

1 Available at the WHO WWW site (http://www.who.ch/programmes/inf/facts/ fact125.htm). 

1 See No. 30, 1996, pp. 229-230.

2 Available on the Internet at the following location: http://www.nih.go.jp/yoken/iasr/198/tpc198.html.