In an outbreak of small round structured virus (SRSV) gastroenteritis at an international AIDS conference 67 people were ill with diarrhoea or vomiting, one requiring admission to hospital. Epidemiological investigations demonstrated that the vehicle of infection was food prepared by a foodhandler who was recovering from a mild gastrointestinal illness. The food most strongly associated with illness, coronation chicken, was prepared by the food handler on the second day after symptoms ceased. The investigation confirms the view that foodhandlers may contaminate food with SRSVs after cessation of symptoms and should remain off work until at least 48 h after recovery.

SUMMARYA total of 100 tropical aquaria from six pet shops were sampled for the presence ofSalmonella, CampylobacterandAeromonasspecies. Eight fish tanks contained unusual serotypes of salmonella. None had been used to house terrapins. One hundred and three isolates ofAeromonasspecies were obtained from 98 tanks. One tank containedPlesiomonas shigelloides.NoCampylobacterspecies were isolated. It is suggested that a tropical aquarium may constitute an infection hazard.

SUMMARYIn an outbreak of plasmid-free Salmonella enteritidis phage type 4 (PT4) food poisoning at a hospital for mentally handicapped people in July 1990, 101 residents and 8 staff were affected and a cohort study implicated beef rissoles cooked by deep-fat frying as the vehicle of infection (relative risk 2f92, 95 % confidence interval 1-73-4v93, P < 0-00 1). Replication of the cooking process demonstrated that the rissoles achieved core temperatures of only 48-60 'C despite external temperatures of 91-95 'C and an oil temperature of 142-154 'C. No residual food was available for microbiological testing but plasmid-containing S. enteritidis PT 4 was isolated in shell eggs from the hospital kitchen.

During the second week after the function, all attenders completed a postal questionnaire enquiring about symptoms and asking them to indicate the foods they did and did not eat from a list of the 13 items available. Ten of 11 submitted faecal specimens. Seven, including the five with symptoms, were positive for S enteritidis PT4. All five with symptoms ate cheesecake, compared with only one out of six guests who did not have symptoms (p=0 013 Fisher's exact test-one tailed). The individual who ate cheesecake but remained well was negative for S enteritidis PT4. The two further individuals positive for S enteritidis PT4 said they did not eat cheesecake.

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