REPEATERS COUNT - A SENTINEL METHOD FOR ASTHMA OUTBREAKS

Background - Asthma outbreaks have not been detected in Barcelona, Spa in since the epidemic of 1981-7. On 29 October 1994 several subjects a ttended a Barcelona because of acute attacks of and were identified as former soybean epidemic asthma patients (repeaters), raising the poss ibility of an asthma soybean-related episode. The usefulness of counti ng repeaters to evaluate small increases of acute asthma in a nonepide mic period is illustrated. Methods - A retrospective identification of asthma admissions was performed, pollution filters collected before a nd after the index day were analysed for contents of low molecular wei ght soybean allergen, and soybean unloading activities were investigat ed. Results - There was no epidemic increase of asthma patients during this day in the whole of Barcelona, but an unusually high number were repeaters (seven observed v 0.483 expected). A relationship with incr eased levels of low molecular weight soybean allergen (U/m(3)) was det ected in the available pollution filters collected the day before and after the index day. Two ships were unloading soybean in the city harb our on the index day. Conclusion - Soybean unloading at the harbour of Barcelona released soybean dust and produced a small cluster of emerg ency room visits for asthma in patients formerly affected by soybean a sthma epidemics. It is suggested that counting repeaters could provide the basis for a systematic epidemiological surveillance of sensitised populations.