During 2005, 580 culture-confirmed cases of Salmonella infection (11.3 per 100,000 population) were reported. This represents a 10% decrease from the 643 cases reported in 2004 and a 7% decrease from the median annual number of cases reported from 1996 to 2004 (median, 626 cases; range, 576 to 693) (Figure 1). Four serotypes, S. Enteritidis (130 cases) S. Typhimurium (120 cases), S. Newport (44 cases), and S. Heidelberg (27 cases) accounted for 55% of cases reported in 2005. There were six cases of S. Typhi infection. Three of the S. Typhi case-patients traveled internationally (India, Pakistan Ethiopia) and developed symptoms during their travel or within 2 weeks of their return; one case-patient arrived in the United States from Thailand approximately 3 months prior to the specimen collection date; one case-patient immigrated from Thailand 15 months prior to specimen collection; and one case-patient was a Hmong immigrant (immigration date unknown). Six percent of salmonellosis case-patients were less than 1 year of age, and 25% were 12 years of age or younger. Twenty-six percent of case-patients were hospitalized for their infection. Of 525 case-patients that were interviewed, 108 (21%) traveled internationally during the week prior to their illness onset.
A 78 year-old case-patient died. The case-patient was hospitalized for nearly 2 months for gastrointestinal symptoms. During her hospitalization, S. Typhimurium was isolated from a diverticular abscess.
Four outbreaks of salmonellosis were identified in 2005. All four outbreaks involved foodborne transmission.
Four S. Heidelberg cases with illness onsets in January through March reported eating frozen, microwaveable stuffed chicken products during the week before illness onset. The implicated product is a raw chicken product coated with a pre-browned breading that gives the appearance of being cooked. Products from a case-patient’s home and product with the same production date purchased at the grocery store tested positive for S. Heidelberg.
A multi-state outbreak of S. Typhimurium infections associated with cake batter flavored ice cream from a national chain of ice cream shops was identified by MDH in June. Twenty-six cases were identified in nine states; five of those cases were Minnesota residents. Case-patients had onsets of illness from May through July. The source of contamination was cake mix that was incorporated in the ice cream without being cooked first.
From June through August, five S. Manhattan cases were identified. A case-control study found that illness was statistically associated with cilantro and pork. Two of the cases attended a funeral where pork and cilantro sandwiches were served. The remaining cases had eaten pork and/or cilantro in their homes.
An outbreak of S. Enteritidis infections associated with eating frozen, microwaveable, stuffed chicken products was identified in 2005. Four case-patients had onsets in August though December. Additional cases with onsets in 2006 are still being reported, so the investigation continues. This was the third outbreak in Minnesota associated with this type of chicken product since 1998. As a result, the United States Department of Agriculture has required label changes to more clearly identify this product as raw, and to have more adequate cooking instructions.
In addition to the four outbreaks in Minnesota, 11 S. Enteritidis cases were part of an outbreak at all-inclusive resorts in Jamaica during January and February. A total of 70 cases from 12 states were identified. The CDC collaborated with Jamaican authorities in the investigation. The outbreak was associated with eggs from a local farm. Pooling of eggs at the resorts, and cross-contamination of other foods most likely contributed to the outbreak. The S. Enteritidis phage-type and PFGE pattern were previously not known to be endemic to Jamaica. Local farms were devastated by Hurricane Ivan in 2004, and may have been repopulated with birds from the United States (where this phage-type and PFGE pattern are endemic). Three additional cases of S. Enteritidis of the same PFGE pattern were identified in Minnesota in travelers to Jamaica from May through October, after the investigation ended.
Note: For up to date information see: Salmonellosis (Salmonella)