CDC Says Salmonella "Over" But Conducting Surveillance
CDC has been working with state, local, and tribal health departments, the Indian Health Service, and the Food and Drug Administration (FDA) to investigate a large, multi-state outbreak of Salmonella Saintpaul. The outbreak appears to be over. However, CDC and state health departments are continuing to conduct surveillance for cases of infection with the outbreak strain. Public health officials also continue to analyze Salmonella data gathered during the investigations.
On May 22, 2008 the New Mexico Department of Health notified CDC of four people ill with the outbreak strain of Salmonella Saintpaul and 15 other persons with Salmonella infection whose isolates had not yet been characterized. In the following weeks, cases of illness with the outbreak strain continued to be reported and the outbreak expanded to include 43 states, the District of Columbia and Canada.
CDC and its public health partners on the federal, state, local, and tribal levels searched for the source of the outbreak and took steps to stop transmission of the infection. The investigators depended on the cooperation of hundreds of ill and well persons across the country who answered questions about what foods they had recently consumed. This allowed investigators to link illness with particular food items. In addition, public health officials in several states, with the assistance of CDC, investigated clusters of ill persons who had eaten at the same restaurants. FDA and state investigators traced the origin of some produce items back through the distribution chain and collected samples to test for the presence of the outbreak strain.
The investigation showed that jalapeño peppers were a major source of contamination and that serrano peppers also were a source. In addition, tomatoes were possibly a source, particularly early in the outbreak. Jalapeño peppers were traced back to distributors in the United States that received produce grown and packed in Mexico. The outbreak strain was isolated from samples of jalapeño peppers collected in a US warehouse and a patient's home and from samples of serrano peppers and water collected on a farm in Mexico. More detailed information about the outbreak investigation and results may be found in the CDC Morbidity and Mortality Weekly Report.
Since April, 1442 persons infected with Salmonella Saintpaul with the same genetic fingerprint have been identified in 43 states, the District of Columbia, and Canada. These were identified because clinical laboratories in all states send Salmonella strains from ill persons to their State public health laboratory for characterization. The number of ill persons identified in each state is as follows: Alabama (8 persons), Arkansas (21), Arizona (59), California (16), Colorado (17), Connecticut (5), Florida (4), Georgia (42), Idaho (6), Illinois (120), Indiana (21), Iowa (2), Kansas (21), Kentucky (2), Louisiana (3), Maine (1), Maryland (39), Massachusetts (31), Michigan (28), Minnesota (31), Mississippi (2), Missouri (20), Montana (1), New Hampshire (6), Nevada (14), New Jersey (16), New Mexico (115), New York (41), North Carolina (28), Ohio (10), Oklahoma (38), Oregon (11), Pennsylvania (15), Rhode Island (3), South Carolina (2), Tennessee (10), Texas (559), Utah (3), Virginia (31), Vermont (2), Washington (18), West Virginia (1), Wisconsin (13), and the District of Columbia (1). Five ill persons are reported from Canada. Four appear to have been infected while traveling in the United States; the travel status of the fifth ill person is unknown.
Among the 1414 persons with information available, illnesses began between April 16 and August 11, 2008 with most becoming ill during May or June; 119 became ill on July 1 or later. These numbers include those with estimated onset dates as well as those with reported onset dates. The latest reported onset date is August 11. The latest estimated onset date is August 7.
Complete demographic information was available for 565 ill people. Of these, 52% were male; 79% were white, 8% were American Indian/Alaska Native, 3% were black, 2% were Asian/Pacific Islander, and 7% reported other or multiple races. Hispanic ethnicity was reported for 22%. Patients ranged in age from <1 to 99 years with a median age of 33 years. The rate of illness was highest among persons 20 to 29 years old. Cases were distributed among 43 states, the District of Columbia, and Canada, with particularly high incidence rates in New Mexico and Texas. At least 286 persons were hospitalized, and the infection might have contributed to two deaths.
The outbreak can be visually described with a chart showing the number of persons who became ill each day. This chart is called an epidemic curve or epi curve. Please see Interpretation of Epidemic Curves During an Active Outbreak. It shows that the number of persons who became ill peaked during May and decreased in June. The average number of persons who became ill in recent weeks continues to decrease, indicating that the outbreak is ending. See the Salmonella Outbreak Investigations: Timeline for Reporting Cases.
Only 18 persons infected with this strain of Salmonella Saintpaul were identified in the country during April through August of 2007. The previous rarity of this strain and the distribution of illnesses in all U.S. regions suggest that the implicated food is distributed throughout much of the country. Because many persons with Salmonella illness do not have a stool specimen tested, it is likely that many more illnesses have occurred than those reported. Some of these unreported illnesses may be in states that are not on today's map.
Clinical features of Salmonella Infection
Most persons infected with Salmonella develop diarrhea, fever, and abdominal cramps 12-72 hours after infection. Infection is usually diagnosed by culture of a stool sample. The illness usually lasts 4-7 days. Although most people recover without treatment, severe infections may occur. Infants, elderly persons, and those with impaired immune systems are more likely than others to develop severe illness. When severe infection occurs, Salmonella may spread from the intestines to the bloodstream and then to other body sites, and can cause death. In these severe cases, antibiotic treatment may be necessary.
Advice to consumers
The U.S. Food and Drug Administration (FDA) has lifted its advice to consumers to avoid eating jalapeño and serrano peppers grown, harvested or packed in Mexico.
The FDA has taken this action consistent with the CDC announcement that the Salmonella Saintpaul outbreak appears to be over, and that jalapeño peppers and serrano peppers grown in Mexico and associated with the Salmonella Saintpaul outbreak are no longer in circulation in the U.S. market.
In July, the FDA lifted its advice to avoid raw red round, red Roma, and red plum tomatoes.
The FDA continues to work with CDC, Mexican authorities, state regulatory agencies and food industry groups to ensure that Americans continue to enjoy one of the safest food supplies in the world.
More information may be found at http://www.fda.gov/oc/opacom/hottopics/tomatoes.html.
Consumers are reminded that vegetables are an important part of a healthy diet and that cooking vegetables kills bacteria, including Salmonella.