An increase in sporadic and outbreak-associated Salmonella enteritidis infections in Wisconsin: the role of eggs.

In Wisconsin, reported Salmonella enterica serotype enteritidis (SE) infections during 1997 more than doubled compared with the previous 9 years. A case-control study was conducted to determine risk factors for sporadic infections, and results of outbreak investigations were reviewed. Eating raw eggs (matched odds ratio [MOR] = 14.5; 95% confidence interval [CI], 1.7-591.6), eating raw or undercooked eggs (MOR = 5.8; 95% CI, 1.3-28.0), eating any eggs (MOR = 4.2; 95% CI, 1.2-16.2), and dining at a restaurant (MOR = 4.7; 95% CI, 1.4-18.4) were associated with infection in the case-control study. For 3 of the 8 outbreaks, a probable source was identified, in each instance, foods containing eggs. Human infections decreased after eggs were diverted from implicated flocks. This epidemic demonstrates the continuing need for quality assurance on egg farms and enhanced education of consumers and commercial food preparers regarding safe handling of eggs.