Minnesota Department of Health (MDH) Bug Bytes

April 29, 2010
Vol. 11: No. 4

Topics in This Issue:
1.  Food Pathogens Incidence Update
2.  Salmonella, Shedding, and Sandwiches
3.  2009 STD and HIV Data
4.  Dengue Warning for Workers in Haiti
5.  Lyme Disease Guidelines Upheld

1.  Food Pathogens Incidence Update

A recent MMWR article (http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5914a2.htm) reported on trends in pathogens transmitted commonly through food as documented by the Emerging Infections Program (EIP) FoodNet Surveillance System, of which we are a part.  In 2009, the 10 U.S. EIP FoodNet sites reported 17,468 laboratory-confirmed cases of Campylobacter, Listeria, Salmonella, Shiga toxin-producing Escherichia coli (STEC) O157, Shigella, Vibrio, Yersinia, Cryptosporidium, and Cyclospora.     

Compared to the first 3 years of surveillance (1996-1998), there were declines in the incidence of Campylobacter (30% decline), Listeria (26%), Salmonella (10%), STEC O157 (41%), Shigella (55%), and Yersinia (53%). Vibrio incidence continued to increase (85%). Compared to the last 3 years (2006-2008), significant decreases in Shigella (27%) and STEC O157 (25%) incidence were seen. For most infections, incidence was highest among children aged <4 years; the percentage of persons hospitalized and the case fatality rate were highest among persons aged ≥50 years.

The incidence of infections with specific Salmonella serotypes in 2009, compared to 1996-1998, was lower for Typhimurium, Agona, Heidelberg, and Thompson, and higher for Javiana, Newport, Oranienburg, and Enteritidis. Compared to 2006-2008, only Oranienburg (35% increase) and I 4,[5],12,i:- (42% decrease) were significantly different. The incidence of postdiarrheal HUS in children aged <5 years and in persons aged <18 years did not change significantly in 2008 compared to 2005-2007.

These important trends data, which are helping to shape national prevention policies at the federal government and by industry, all start with the disease report submitted by you the clinician or infection control preventionist, and the isolate submitted by you the microbiologist.  So, thank you all.

Learn more about: Foodborne Illness>>


2. Salmonella, Shedding, and Sandwiches

We recently published an article documenting yet another instance in which an asymptomatic food handler was the source of a restaurant-associated foodborne outbreak (J Food Protection 2009 72;11:2331-6). Salmonella is the most common bacterial cause of foodborne outbreaks in the United States; approximately half of all Salmonella outbreaks occur in restaurant settings.

In February 2008, we investigated an initial cluster of 5 S. Enteritidis cases with indistinguishable PFGE patterns; all 5 had eaten at the same restaurant. We initiated a case control study of 15 cases and 37 controls consisting of well meal companions and well patrons contacted via check stubs. Sandwiches were the only menu item or ingredient significantly associated with illness. Illness histories and stool samples were collected from all restaurant employees. None of the 6 restaurant employees reported experiencing recent gastrointestinal symptoms. The outbreak PFGE subtype of S. Enteritidis was identified in 2 food workers. One of the positive employees began working at the restaurant shortly before the first exposure date reported by a case, and assisted in the preparation of sandwiches and other foods consumed by cases. The other positive employee rarely, if ever, handled food. Illness was also associated with sandwiches served at a catered event; the sandwiches were prepared by the first positive employee and a second employee who tested negative. The restaurant did not have a glove use policy. There was no evidence of ongoing transmission after exclusion of the positive food workers.

Transmission may have been facilitated because the infected food worker was new to food service, prepared ready-to-eat food items during training, and had extensive bare hand contact with these items. Our report emphasizes the importance of following proper hand washing and food handling procedures in food service facilities. Although asymptomatic food workers shed Salmonella for a shorter period on average than those who reported gastrointestinal illness (median of 3 days versus 30 days), shedding occurred for up to 97 days in asymptomatic food workers. Testing of employees, regardless of illness history, is important in restaurant outbreaks of salmonellosis as a means to end transmission to patrons and other employees.

Learn more about: Salmonella>>

3. 2009 STD and HIV Data

The total number of reportable sexually transmitted diseases (STDs; chlamydia, gonorrhea, syphilis, and chancroid) in Minnesota dropped 5% from 2008 to 16,702 in 2009. Chlamydia was the number one reported STD in 2009 with 14,186 cases. Chlamydia occurs statewide with about 1 in 3 cases occurring in the Greater Minnesota areas. Gonorrhea remained the second most commonly reported STD with 2,302 cases reported in 2009, a 24% decrease compared to 2008. Nationally, preliminary data show a 21% drop in gonorrhea cases in 2009. There was a 28% decrease in the number of early syphilis cases reported in 2009 (117 cases), while the percentage of those co-infected with syphilis and HIV rose by 5% to 45%.

There were 370 HIV/AIDS cases reported in 2009, the most in over a dozen years.  As of December 31, 2009, a cumulative total of 9,163 cases of HIV infection have been reported among Minnesota residents including 5,655 AIDS cases and 3,508 HIV, non-AIDS cases. Of these 9,163 HIV/AIDS cases, 3,056 are known to be deceased.

The HIV data are posted at: http://www.health.state.mn.us/divs/idepc/diseases/hiv/hivsurvrpts.html. The STD data are posted at: http://www.health.state.mn.us/divs/idepc/dtopics/stds/stdstatistics.html.

Learn more about: Sexually Transmitted Diseases>>

4. Dengue Warning for Workers in Haiti

Dengue is one of the most commonly reported mosquito-transmitted diseases throughout tropical and subtropical regions of the world. While dengue virus is not endemic to Minnesota, residents may be exposed to infected mosquito vectors when they travel to these regions. From 2005 through 2009, 59 dengue cases (median, 9 cases/yr, range, 6-20 cases) in Minnesota residents were reported to us, including 7 cases in 2008 that traveled to the Dominican Republic as part of a group doing missionary work.

Dengue is endemic in Haiti and the recent earthquake there caused extensive damage and increased opportunities for mosquito breeding. Relief workers responding to previous disasters in Haiti reported high rates of dengue infection. The CDC advises physicians evaluating travelers returning with a febrile illness (or a recent history of febrile illness) from Haiti consider dengue.

Dengue fever (DF) is characterized by high fever and headache, retro-orbital pain, joint pain, muscle or bone pain, rash, mild hemorrhagic manifestations (e.g., nose or gum bleed, petechiae, or easy bruising), and leukopenia. The incubation period for DF ranges from 3 to 14 days but is typically about 1 week. Most DF cases are self-limited but a small proportion develop dengue hemorrhagic fever (DHF), which is characterized by presence of resolving fever or a recent history of fever lasting 2–7 days, hemorrhagic manifestations, thrombocytopenia (platelet count <100,000/mm3), and abnormal vascular permeability evidenced by hemoconcentration, hypoalbuminemia, or abdominal or pleural effusions. DHF can result in circulatory instability or shock, and the risk for these complications may be increased among persons with prior dengue infection.

Physicians seeing a patient who has illness consistent with dengue, as described above, and who has recently traveled to Haiti should seriously consider laboratory testing. Initiation of supportive care should not be delayed pending test results. While some commercial labs offer diagnostic services for dengue, these labs are not always able to provide results that can distinguish recent from past dengue infection. Physicians should collect specimens from patients who have symptoms consistent with dengue infection and who have traveled to Haiti within the past 30 days, and should consult with us to arrange for dengue testing which will be conducted at CDC. Whenever possible, physicians should submit paired acute and convalescent samples to facilitate optimal diagnostic testing.

Learn more about: Mosquito-Transmitted Diseases>>

5. Lyme Disease Guidelines Upheld

In 2006, the Infectious Diseases Society of America (IDSA) released guidelines for the diagnosis and treatment of Lyme disease, anaplasmosis, and babesiosis. Some Lyme disease patient advocacy groups and a minority of physicians disagreed with certain aspects of these guidelines. Particular points of contention included the existence of "chronic Lyme disease" and the merit of long-term antibiotic therapy for persons with persistent complaints after initial treatment. Subsequently, the Connecticut Attorney General (AG) brought an anti-trust lawsuit against IDSA for these guidelines. The case was settled with an agreement to review the guidelines. The IDSA and the AG jointly selected an ombudsman, Dr. Howard Brody, an author and respected medical ethicist at the University of Texas Medical Branch. Dr. Brody screened all potential Review Panel members for conflicts of interest using criteria jointly approved by the AG and IDSA. The Review Panel was comprised of 9 scientists and physicians from relevant disciplines who had not served on any previous Lyme disease guidelines panel. 

On April 22, the IDSA announced that the Review Panel unanimously upheld the guidelines (see http://www.idsociety.org/Content.aspx?id=16501). The Panel stated that all of the 2006 guidelines are medically and scientifically justified in light of the evidence and information provided, including the recommendations that are most contentious: that there is no convincing evidence for the existence of chronic Lyme infection, and that long-term antibiotic treatment of “chronic Lyme disease” is unproven and unwarranted. Inappropriate use of antibiotics (especially given intravenously) has been shown to lead to other infections such as Clostridium difficile, drug reactions, as well as the creation of antibiotic-resistant bacteria.

Learn more about: Lyme Disease (Borrelia burgdorferi)>>


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.

For concerns or questions regarding content, please use our Bug Bytes Feedback Form.

You can also subscribe to the MDH Bug Bytes newsletter.

Updated Wednesday, 30-Mar-2011 13:53:55 CDT