Minnesota Department of Health (MDH) Bug Bytes

October 7, 2008
Vol. 9: No. 7

Topics in this Issue:

1. Salmonellosis, Frozen Chicken Entrees, and Microwave Ovens, Again
2. Transfusion-Associated Babesiosis, Again
3. Cryptosporidiosis Outbreak, Again
4. Lyme Disease Breaks Record, Again
5. Uncalled For Post-Game Festivities
6. Register Now for Emerging Infections Conference

1. Salmonellosis, Frozen Chicken Entrees, and Microwave Ovens, Again

In the August 5, 2008 Bug Bytes we discussed our discovery and pending publication of a journal article of an emerging problem of salmonellosis associated with frozen stuffed chicken products. During 1998-2006, we investigated four salmonellosis outbreaks associated with raw, frozen, microwaveable, breaded and pre-browned, stuffed chicken products. A range of 3 to 33 confirmed salmonellosis cases occurred in these outbreaks, and the individual outbreak serotype and PFGE subtype of Salmonella was isolated from product in each outbreak. In these outbreaks, most cases thought that the product was pre-cooked due to its breaded and pre-browned nature, most used a microwave oven, most did not follow package cooking instructions, and none took the internal temperature of the cooked product. Inadequate labeling, consumer responses to labeling, and microwave cooking were the key factors in the occurrence of these outbreaks. Modification of labels, verification of cooking instructions by the manufacturer, and notifications to alert the public that these products contain raw poultry, implemented because of the first two outbreaks, did not prevent the other outbreaks. Microwave cooking is not recommended as a preparation method for these types of products, unless they are pre-cooked or irradiated prior to sale. We have been working with distributors and manufacturers of these products on ways to further improve the labeling and instructions to consumers that they should not use microwaves to cook these raw products.

To our dismay, we are currently investigating an outbreak of Salmonella 4, 12: i: - cases associated with the same type of product. Since July 2008, we have seen 14 cases in Minnesota with the same PFGE pattern. Six Minnesota cases with specimen collection dates since August 23, 2008 reported eating Milford Valley Farms Chicken Cordon Bleu and/or Chicken Kiev products (plant code P-2375). Two cases had unopened packages of the product in their freezers with production codes of C8126 and C8133 for the Chicken Cordon Bleu, and C8149 for the Chicken Kiev. S. 4, 12: i: - of the outbreak PFGE subtype was isolated from four packages of the product recovered from the cases’ homes and grocery stores, with the production code of C8133. S. Enteritidis, S. Typhimirium, and S. Infantis were also recovered from additional packages that were tested. Eighteen other cases in 11 other states with matching serotypes and PFGE subtypes have been identified.

This manufacturer had changed its label and the brand is no longer marketed as microwaveable; however, five of our cases reported cooking the product in the microwave. We issued a press release last week to warn consumers.  In turn, the U.S. Department of Agriculture issued a nationwide alert. 

Learn more about: Salmonella>>
Learn more about: Food Recalls>>

2. Transfusion-Associated Babesiosis, Again
Babesiosis is a rare malaria-like disease caused by Babesia microti, an intraerythrocytic protozoan transmitted by the bite of Ixodes scapularis, the blacklegged or deer tick. In 2002, in the journal Transfusion, we reported a case of transfusion-associated babesiosis from a fall 1999 blood donation. Last year, in Bug Bytes, we described a September 2006 investigation of transfusion-associated babesiois. An elderly, asplenic male with cancer and a history of recent blood transfusions was hospitalized for an acute febrile illness. Tests for B. microti DNA, and blood smear were positive, and the patient died within a month of symptom onset. A trace-back of 10 donors of blood transfused into the index case resulted in finding one donor testing positive for B. microti antibody. The implicated donor reported no history of babesiosis symptoms in the past year but frequently traveled to an endemic area in Minnesota.
Another likely case of transfusion-associated babesiosis was recently reported to us. A Twin Cities resident greater than 90 years of age presented to an ED in mid-September with rapidly declining mental status and decreased hemoglobin, and died soon thereafter. The patient was smear-positive for Babesia sp. inclusions and PCR positive for B. microti. The patient had minimal outdoor exposure but had received two units of red cells in late August. The American Red Cross is conducting a donor trace-back. A retained blood sample from one of the two donors tested positive for B. microti by PCR. This donor was likely exposed in an endemic area of Wisconsin.

Although babesiosis is rare in Minnesota (75 reported cases, 2001-2007) compared to the state’s other blacklegged tick-transmitted diseases, Lyme disease and human anaplasmosis, it can be severe or fatal in patients who are asplenic, elderly, or otherwise immune compromised. Most B. microti infections in healthy individuals are sub-clinical, and parasitemia may persist for months. A large volume blood donor screening assay for B. microti does not exist. Therefore, asymptomatic carriers who donate blood are a potential source of transfusion-transmitted babesiosis and transfused patients are at slight risk of acquiring B. microti infection. Physicians should include babesiosis in their rule-out for patients who develop acute febrile illness and hemolytic anemia following a blood transfusion, especially those with asplenia, advanced age, or otherwise immune compromised.

Learn more about: Babesiosis>>


3. Cryptosporidiosis Outbreak, Again

We are investigating an outbreak of cryptosporidiosis at a water park. This is the same water park that had a cryptosporidiosis outbreak in September 2007. This year’s outbreak was identified by molecular subtyping of Cryptosporidium isolates submitted to our laboratory in conjunction with routine surveillance interviews. There are two confirmed cases from separate households who reported swimming at the water park on August 13 and 14 respectively. There were no known fecal incidents or breaches in the system that occurred on the days of interest.

Cryptosporidium oocysts are resistant to and can survive for several days in the chlorine levels typically recommended for swimming pools (1-3 ppm. free chlorine). Therefore, rapid detection and response are needed to prevent ongoing transmission and subsequent expansion to other water venues. The number of cryptosporidiosis outbreaks reported annually in the United States has increased substantially from nine in 1997-1998 to 31 in 2005-2006.  Two thirds of the gastroenteritis waterborne disease outbreaks reported nationally in 2005-2006 were due to cryptosporidiosis. Most outbreaks associated with treated water venues are due to cryptosporidiosis.

Learn more about: Cryptosporidiosis>>


4. Lyme Disease Breaks Record, Again

In last week’s MMWR (at http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5710a1.htm) was an article summarizing Lyme disease surveillance for the United States for 1992-2006. Lyme disease is the most commonly reported vectorborne disease in the United States with over 248,000 cases reported in this time period, with large increases seen in recent years. In Minnesota, in 2007, 1,239 confirmed Lyme disease cases were reported. This is a 36% increase from the 913 cases in 2006, and substantially higher than the 918 cases in 2005 and the previous record number of 1,023 cases in 2004. The frequency of Lyme disease since 2004 has been markedly higher than the median number of cases reported annually from 1996 through 2003 (median, 374 cases; range, 252 to 866).

Learn more about: Lyme Disease>>


5. Uncalled for Post-Game Festivities

On Sunday, September 7, we received an illness complaint associated with a taco party held for a high school football team in a private home after a game on September 5. The celebration included approximately 70 players and parents, and the initial report indicated that most had become ill the following day. 

We interviewed 26 attendees. Of these, 16 (62%) met our illness case definition (diarrhea; at least 3 loose stools in a 24-hour period); 5 (19%) additional individuals reported gastrointestinal illness symptoms but did not meet the case definition. The median incubation period was 8.5 hours (range, 6.5 to 12 hours). The median illness duration was 13.5 hours (range, 5 to 50 hours). All cases reported diarrhea, 11 (73%) reported cramps, and 1 (7%) reported vomiting; none reported fever or bloody diarrhea. None were hospitalized. Clostridium perfringens was isolated from stool samples from all 4 cases who submitted a sample. Two stool samples were positive for C. perfringens enterotoxin A. 

Taco meat was implicated as the vehicle. Consumption of several food items served at party was significantly associated with illness including taco meat (15 of 15 cases consumed taco meat vs. 1 of 4 controls; odds ratio, undefined; lower limit 95% confidence interval, 4.9 to undefined; p = 0.001). C. perfringens was cultured from leftover taco meat at a level of 6.6 x 107 organisms per gram. That’s high: levels of 105 or greater per gram in food indicate that food as a likely vehicle.

The taco meat was prepared on Thursday using 30 lbs. of ground beef. The ground beef was fried, and then the taco seasoning was added. The prepared taco meat was divided into two containers and refrigerated in a home refrigerator until the event the following evening. The taco meat was reheated prior to serving. Temperatures were not taken during the cooking, cooling, or reheating process. 

C. perfringens is ubiquitous and a relatively common cause of foodborne outbreaks. C. perfringens food poisoning is characterized by onset of abdominal cramps and diarrhea 8-16 hours after eating contaminated meat or poultry Outbreak vehicles frequently are meats or meat-based gravies. C. perfringens spores survive normal cooking methods; subsequent temperature abuse of foods allows amplification of the vegetative form of the organism. This vegetative form is susceptible to cooking; it is only when foods are not thoroughly reheated that C. perfringens can survive to produce toxin after it is ingested. A danger zone exists between 70°F and 120°F. Foods need to be cooled rapidly through this zone on their way down to 41°F and lower. If served without adequate reheating, live vegetative forms of C. perfringens may be ingested. The bacteria then elaborate the enterotoxin that causes the characteristic symptoms of diarrhea and abdominal cramping. It is likely here that too much taco meat was placed into each container, preventing rapid cooling of the food and allowing C. perfringens to amplify. The taco meat was then improperly reheated before serving.

Learn more about: Cooking for Groups>>
Learn more about: Foodborne Illness>>

6. Register Now for Emerging Infections Conference

The 14th Annual Emerging Infections in Clinical Practice and Public Health will be held Friday November 14 at the Minneapolis Radisson University Hotel. Come hear about emerging infections and global warming, MRSA, travel medicine, and more. More information and registration information is at https://cme.ahc.umn.edu/Scripts/4Disapi.dll/4DCGI/events/ConferenceList.html?Action=GetEvents


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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Updated Tuesday, June 03, 2014 at 02:35PM