Do changes in the incidence of occupationally-acquired food-borne zoonotic infections precede changes in the wider population

Objectives Recently the WHO estimated that up to 75% of emerging pathogens may be of zoonotic origin. Occupationally acquired zoonoses are of particular concern in food producing sectors because of the possibility of transmission through the food chain. We aim to investigate whether changes in incidence of occupationally-acquired zoonotic infections in agricultural and veterinary workers or food preparation and food retail workers are useful in predicting changes in the incidence of food-borne zoonotic infections in the wider population.

Methods In the UK infectious disease consultants report cases of occupationally acquired infectious disease to the Surveillance of Infectious Diseases at Work (SIDAW) scheme. Cases reported to SIDAW will be analysed using a 2 level negative binomial regression model adjusted for changes in the size of occupational group at risk as described elsewhere1. Following a target set by the UK Health Protection Agency (HPA) in 2001 to reduce the incidence of salmonella in UK produced chicken there has been a declining trend in outbreaks of food-borne salmonellosis. In contrast there has been little change in the number of outbreaks of food-borne camphylobacteriosis reported to the HPA over the same time. These trends reported to the HPA will be compared with SWORD data.

Results Between 1997 and 2010, 244 individual cases (209 outbreaks) of salmonellosis and 577 individual cases (522 outbreaks) of camphylobacterosis were reported to SWORD. Over the same time period 590 foodborne outbreaks of salmonellosis and 105 of camphylobacterosis were reported to the HPA. A simultaneous decline in the incidence of salmonellosis reported to SWORD and food-borne salmonellosis reported to the HPA was observed. These data will be analysed further to compare different occupational sectors.

Conclusion Reporting of occupational infectious diseases in some sectors may be a useful marker for changes in incidence occurring in the wider population.