a1 Public Health Laboratory Service, Communicable Disease Surveillance Centre (Welsh Unit), Cardiff
a2 Department of Public Health Medicine, South Glamorgan Health Authority, Abton House, Wedal Road, Roath, Cardiff CF4 3QX
An outbreak of non-bacterial food poisoning presumed due to small round, structured viruses (SRSV) occurred at a national conference.
A detailed postal survey of all conference attenders was carried out to ascertain the cause of the outbreak and 355 questionnaires were returned.
Univariate analysis showed that mussels in the seafood cocktail were the likely vehicle of infection. A dose–response relationship between the amount of seafood cocktail consumed and the risk of illness was demonstrated. Dose–response has not previously been documented in a food-borne outbreak due to small round structured virus.
Detailed quantitative food histories can be useful in eliciting dose-response relationships and may be crucial in establishing the vehicle of infection when investigating food poisoning following consumption of a set-menu meal. Their use should be considered in other outbreak situations.
(Accepted November 24 1992)