Salmonellosis, 2011

During 2011, 701 culture-confirmed cases of Salmonella infection (13.2 per 100,000 population) were reported. This represents a 5% increase from the median annual number of cases reported from 2001 to 2010 (median, 668 cases; range, 578 to 755). Of the 91 serotypes identified in 2011, 5 serotypes, S. Enteritidis (173), S. Typhimurium (105), S. I 4,[5],12:i:- (60), S. Newport (55), and S. Infantis (20) accounted for 59% of cases. Salmonella was isolated from stool in 615 (88%), urine in 44 (6%), and blood in 32 (5%) cases. Other specimen sources included abscesses, bone, endometrium, placenta, tissue, leg laceration, and a toe swab. There were 3 cases of S. Typhi infection; 2 had travelled to India and 1 to Pakistan. There were 3 cases of S. Paratyphi A infection; 1 had travelled internationally (India).

Of the 648 cases interviewed about travel history, 91 (14%) had traveled internationally during the week prior to their illness onset. Cases who reported Asian race had a higher incidence (25.4 per 100,000 population) than any other reported race (Black, 15.7; Native American, 12.8; White, 10.7). One 81-year-old case died of congestive heart failure secondary to type 2 diabetes mellitus 8 days after S. Javiana was isolated from a urine sample. Seventy-three cases were part of 13 Salmonella outbreaks identified in 2011. Eight outbreaks involved cases in multiple states. Ten of the outbreaks involved foodborne transmission and three outbreaks were due to animal contact. The 13 outbreaks resulted in a median of 3 culture-confirmed cases per outbreak (range, 1 to 16 cases). In February, 3 cases of S. Enteritidis infection were part of an outbreak at a wedding reception. An undercooked chicken dish was the suspected vehicle. In February, 3 cases of S. Agona infection were part of a multi-state outbreak of 106 cases in 25 states. Papayas imported from Mexico by a single distributor in Texas were implicated as the vehicle and a national recall was initiated. Sampling of papayas from Mexico during the outbreak showed a 15.6% Salmonella contamination rate.

In April, 2 cases of S. Heidelberg infection were part of a multi-state outbreak involving two strains of S. Heidelberg and 136 cases in 34 states. Commercially distributed ground turkey products were implicated as the vehicle. The outbreak led to a national consumer alert and a ground turkey recall. In May, 1 case of S. Altona infection was associated with a multi-state outbreak that involved 45 cases in 15 states. Contact with baby chicks originating from a single mail order hatchery in Ohio was identified as the cause of the outbreak.

In June, 11 cases of S. Muenchen infection were associated with a multi-state outbreak involving 24 cases in 7 states. Commercially distributed iceberg lettuce was the suspected vehicle.

In June, 1 case of S. Uganda infection was part of a multi-state outbreak of 13 cases in 7 states. Cantaloupe was the likely vehicle, but the source of the cantaloupe was not identified.

In July, 4 cases of S. Newport infection were part of a multi-state outbreak of 6 cases in Minnesota and North Dakota that was associated with sandwich chain restaurants. Epidemiological and traceback investigations suggested that cucumbers or tomatoes were the likely vehicle.

In July, 8 cases of S. Typhimurium infection were associated with an outbreak at a Mexican-style restaurant. The outbreak occurred during the State of Minnesota government shutdown and therefore we were unable to perform an ingredient-specific investigation and analysis. The ultimate source of the outbreak was not identified.

In August, 14 cases of S. Typhimurium infection were likely associated with consumption of seedless watermelon that traced back to companies in the same area in Indiana. Five of the cases attended a family gathering where the watermelon was served.

In August, 1 case of S. I 4,[5],12:i:- infection was associated with an ongoing multi-state outbreak associated with rodents used to feed reptiles. Frozen mice from a pet store in another state where a case purchased mice tested positive for the outbreak strain. The same strain was the cause of a 2010 outbreak associated with feeder rodents; this strain may now be endemic in feeder rodent populations in the United States.

In August, 1 case of S. Sandiego infection was part of a multi-state outbreak involving 5 strains of 3 Salmonella serotypes and a total of 124 cases in 27 states. Small turtles were implicated as the vehicles in the outbreak. In September, 8 cases of S. Enteritidis infection were associated with consumption of shell eggs from an organic egg supplier in Minnesota. Environmental samples from the egg belt at the supplier’s packing plant tested positive for the outbreak strain of Salmonella, and a recall and press release were issued.

From May through December, 16 cases of Salmonella infection (including 14 S. I 4,[5],12:i:- cases, 2 S. Rissen cases, and 1 S. Infantis case) were part of an outbreak associated with exposure to live animal slaughter markets. Environmental samples from one market yielded these 3 Salmonella serotypes as well as 7 additional serotypes. Disease prevention measures at the markets are being implemented.

• For up to date information see>> Salmonellosis (Salmonella)
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2011