Minnesota Department of Health (MDH) Bug Bytes
December 13, 2000
Vol. 1: No. 10
1. Influenza Confirmed in Minnesota
The MDH Public Health Laboratory has confirmed influenza in two Minnesota residents. A 5-year old male Kandiyohi County resident was culture positive for influenza A/New Caledonia-like (H1N1). The specimen was collected on December 4 at Affiliated Medical Center (ACMC) in Willmar. ACMC is part of the Sentinel Influenza Surveillance Network. Health care providers who are interested in learning more about this Network, please contact us at 651-201-5414. Additionally, an infant female resident of Ramsey County was culture positive for influenza B/Yamanashi-like (antigenically similar to B/Beijing); her specimen was collected on December 4 at Children's Hospital in the metropolitan area. Nationwide, A/New Caledonia (H1N1) is the predominant circulating strain. Both A/New Caledonia (H1N1) and B/Beijing influenza strains are included in the 2000-2001 influenza vaccine. Historically, influenza activity peaks 6 to 8 weeks after identification of the first virus, so there is still time to receive an influenza vaccination. The CDC provides weekly updates on influenza activity throughout the nation which can be found on this website: http://www.cdc.gov/ncidod/diseases/flu/weekly.htm. Attention: Non-MDH link
2. E. coli O157:H7 Outbreak Update As Bug Bytes went to press on December 1, we announced preliminary results of an E. coli O157:H7 outbreak investigation. We had evidence of 15 cases, all of the same PFGE subtype. A case-control study demonstrated an association with consumption of ground beef purchased at Cub Foods. We have documented a total of 32 cases with the outbreak strain; 17 patients have been hospitalized and 2 had hemolytic uremic syndrome (HUS). Two additional HUS cases may be associated with this outbreak. Onset of illness ranged from 11/11/00 to 12/2/00. In most instances case-patients reported consumption of ground beef from Cub Foods in the 5 days prior to their illness. E. coli O157:H7 of the same PFGE subtype was isolated from opened and unopened packages of ground beef retrieved from patient's homes and individual Cub Foods stores. The Minnesota Department of Agriculture traced the ground beef back to a meatpacker from Green Bay, Wisconsin. The U.S. Department of Agriculture Food Safety and Inspection Service worked with the packer and initiated a voluntary recall of 1.2 million lbs. ground beef produced at the plant on 11/2/00 and 11/3/00. We continue to investigate the source and extent of the outbreak in order to determine if a wider recall should be initiated. Lessons learned from this outbreak for Bug Bytes readers: 1) Only 12% of the production from 11/2-11/3 went to Minnesota. The rest went to 15 other states; yet, additional cases with the same PFGE subtype have been reported only from Wisconsin (3 cases) and Iowa (1 case). Why weren't cases reported from other states? We suspect it's partly due to your and our efforts. Minnesota clinicians are ordering stool cultures and laboratories are appropriately screening for E. coli O157:H7. Few laboratories have shifted to antigen detection in lieu of stool culturing. Thanks to terrific cooperation, laboratories are submitting isolates to MDH where real-time isolate confirmation and PFGE subtyping is conducted. 2) HUS surveillance is important. A few Minnesota disease reporters have been reluctant to report HUS cases to us. Once again, this outbreak has shown the utility of HUS surveillance. All four HUS cases reported had a history of eating ground beef from Cub (two were interviewed before we recognized the outbreak). Initially, only one of the four had been culture-confirmed as E. coli O157:H7 (same PFGE subtype), included in the initial case-control study. We encouraged stool culturing of the other three; one cultured positive and results are pending for the other two. These cases were an early indicator to us of an outbreak. Furthermore, early stool culturing of any HUS patient is important to determine the source of infection. 3) The cooperation of physicians, laboratories, infection control professionals, local health departments, the Department of Agriculture, and industry officials were key to early recognition and ongoing case reporting, control measures, and public education.
3. Viral Meningitis
Viral or aseptic meningitis cases are winding down for this season. From July through November, 89 cases were reported to the MDH as compared with 63 in 1999 and 303 in 1998. The majority of the CSF isolates sent to the Public Health Lab this year are Coxsackievirus B5. All cases of meningitis are reportable to MDH.
4. E. coli O157:H7 Outbreak Update
Total number of confirmed cases in Minnesota is 38. Two of these are confirmed HUS cases; 2 additional HUS cases are epi-linked but are not confirmed as E. coli O157:H7.
Bug Bytes is a combined effort of the Infectious Disease Epidemiology, Prevention and Control Division and the Public Health Laboratory Division of MDH. We provide Bug Bytes as a way to say THANK YOU to the infection control professionals, laboratorians, local public health professionals, and health care providers who assist us.
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