A case control study comprising 282 cases and 319 matched controls was conducted in Denmark during 1996–7. Two estimates of the odds ratio (OR) were determined for each risk factor with and without ‘protective factors’ fitted into the final model. Consumption of undercooked poultry (OR 4·5; 8·2), consumption of red meat at a barbecue (OR 2·3; 4·1), consumption of grapes (OR 1·6; 2·8) and drinking unpasteurized milk (OR 2·3; 11·8) were identified as risk factors in both models. Frequent consumption of pork chops (OR 4·4) and daily contact with domestic animals and pets were identified as risk factors in one of the two models only. Finally, foreign travel was found to be a significant risk factor (OR 2·5). Seasonal and regional interaction was observed for several risk factors and the time elapsed from interviewing of cases to interviewing of controls seemed to influence the effect of certain seasonal dependent risk factors.

We integrated data on quinolone and macrolide susceptibility patterns with epidemiologic and typing data from Campylobacter jejuni and C. coli infections in two Danish counties. The mean duration of illness was longer for 86 patients with quinolone-resistant C. jejuni infections (median 13.2 days) than for 381 patients with quinolone-sensitive C. jejuni infections (median 10.3 days, p = 0.001). Foreign travel, eating fresh poultry other than chicken and turkey, and swimming were associated with increased risk for quinolone-resistant C. jejuni infection. Eating fresh chicken (of presumably Danish origin) was associated with a decreased risk. Typing data showed an association between strains from retail food products and broiler chickens and quinolone-sensitive domestically acquired C. jejuni infections. An association between treatment with a fluoroquinolone before stool-specimen collection and having a quinolone-resistant C. jejuni infection was not observed.

Increased consumption of fresh poultry in Denmark has contributed substantially to the increasing incidence of human campylobacteriosis.

No abstract

In a prospective case-control study of sporadic Salmonella Enteritidis infection in Denmark (1997-1999), foreign travel was reported by 25% of 455 case patients and 8% of 507 controls (odds ratio (OR) = 3.7, 95% confidence interval (CI): 2.4, 5.5). Among nontravelers, 80% of 335 cases and 81% of 467 controls had consumed eggs or dishes containing raw or undercooked eggs during the week before disease onset or interview, while 35% of cases and 19% of controls had incurred this exposure the day before onset or interview (OR = 2.2, 95% CI: 1.5, 3.1). Specific exposures included consumption of buttermilk dessert (OR = 11.7), homemade ice cream (OR = 4.3), raw eggs (OR = 3.4), and eggs fried "sunny side up" (OR = 2.5). Among persons who had used eggs in the week before disease onset or interview, eggs from battery laying hens were associated with disease (white eggs: OR = 2.4, brown eggs: OR = 1.9), whereas consumption of pasteurized eggs tended to be protective (OR = 0.3). The study confirmed that eggs are the principal source of S. Enteritidis in Denmark. This conclusion was reached through the use of an exposure time window that corresponds to the most relevant incubation period rather than the maximum incubation period. The authors recommend this method in studies that have the objective of determining risk associated with common exposures.