Minnesota Department of Health (MDH) Bug Bytes

July 19, 2003
Vol. 4: No. 8

Topics in this Issue:
1. First 2003 Human West Nile Virus Case
2. E. coli O157:H7 Delivered to Your Door
3. Revised Recommendations for the Treatment of Tuberculosis
4. August is "Submit a Bat for Rabies Testing Month"
5. Legionnaires' Anniversary

1. First 2003 Human West Nile Virus Case
Today we are reporting the first probable human case of West Nile Virus (WNV) in Minnesota for 2003. An 80 year-old male from Faribault County had onset of fatigue, headache, and difficulty walking on June 15 and was hospitalized. Serum was positive for (WNV) IgM antibody at both a hospital laboratory and at MDH.

Arboviral transmission season is still just getting underway in the U.S. with low numbers of reports of WNV-positive birds, mosquitoes, and horses from 32 states. To date, 5 other human WNV cases have been reported this year from South Carolina (1 case), Alabama (1 case) and Texas (3 cases). In Minnesota, we also have had 3 equine cases (in Crow Wing, Sherburne and Washington counties) and 6 positive birds (in Hennepin, Ramsey, Washington, and Dakota counties). The public is encouraged to report dead/dying birds to us via our website (at www.health.state.mn.us/divs/idepc/
). As in past years, we still expect the greatest risk to humans to be from mid-July through mid-September.

Physicians should call us at 651-201-5414 or 1-877-676-5414 to report suspect cases of WNV and/or arrange for laboratory testing with us.

2. E. coli O157:H7 Delivered to Your Door
In late June, we detected a multi-state outbreak of E. coli O157:H7 infections linked to frozen, vacuum-packed steaks sold door-to-door by vendors from Farmers Pride Meat Company. Timely interviewing of all reported cases and pulsed-field gel electrophoresis (PFGE) subtyping of isolates submitted by clinical labs to us were critical to the detection of this outbreak. In Minnesota, there have been 4 culture-confirmed and 2 probable cases of E. coli O157:H7 linked to this outbreak. Three of these case-patients were hospitalized; one adult case-patient developed hemolytic uremic syndrome (HUS) and was hospitalized for over 3 weeks. There also have been outbreak-associated cases confirmed in Kansas, Iowa, Michigan, and North Dakota. E. coli O157:H7 matching the outbreak strain has been isolated from unopened, vacuum-packed bacon-wrapped fillets collected from cases in Minnesota and Michigan.

The investigation led Stampede Meats, Inc. of Chicago, IL to announce a nationwide recall of approximately 739,000 lbs. of meat. The recall information can be viewed at:

Steaks are an unusual vehicle for E. coli O157:H7. The steaks implicated in this outbreak were injected with tenderizers and flavoring solutions; this process likely contributed to the outbreak. If E. coli O157:H7 contamination was transferred to the inside of the steak, cooking the surface would not have been adequate to kill the bacteria.

We would like to remind you to report all suspected or confirmed cases of E. coli O157:H7 or HUS to us at 651-201-5414 or 1-877-676-5414.

3. Revised Recommendations for the Treatment of Tuberculosis
Revised national guidelines for the treatment of tuberculosis (TB) disease were recently published (available at www.cdc.gov/mmwr/preview/
). The guidelines, "Treatment of Tuberculosis," were developed jointly by the American Thoracic Society, the Centers for Disease Control and Prevention, and the Infectious Diseases Society of America. They replace the 1994 guidelines.

The newest aspects of therapy include four recommended regimens for treating persons with drug-susceptible TB. Regimens are rated according to the strength of the evidence supporting their use. Each regimen consists of an initial phase of 2 months followed by the choice of several options for a continuation phase of 4-7 months. Directly observed therapy (DOT) is strongly recommended for all TB patients, based on the high rates of treatment completion that are associated with this intervention. Special attention is given to the need to closely monitor the patient's response to therapy in order to select the appropriate regimen; the choice of regimen for the continuation phase depends, in part, on the presence or absence of cavities on the initial chest x-ray and the patient's sputum culture result after 2 months of treatment.

The guidelines also address the collaborative aspects of organizing and supervising TB treatment for each individual patient. For example, the guidelines address issues pertinent to both clinicians and public health professionals, including the role of the health department in monitoring treatment decisions and outcomes; managing adverse drug effects, treatment interruptions, and relapse/treatment failure; the emerging role of fluoroquinolones in the treatment of TB; drug interactions; and treatment of special populations, including children and adolescents, pregnant women, and persons with HIV infection. Of special note for clinicians in Minnesota, where approximately 80% of TB cases occur among foreign-born individuals, the guidelines include detailed recommendations for treating drug-resistant TB and extra-pulmonary TB and also include an informative comparison of TB diagnosis and treatment practices in low-income countries and industrialized countries.

The new guidelines emphasize that appropriate treatment of TB benefits both the individual patient and the larger community by rapidly rendering the patient noninfectious and preventing the emergence of drug-resistant strains of TB. In a significant philosophical departure from previous guidelines, the responsibility for successful treatment - which includes not only prescribing an appropriate regimen, but also ensuring adherence to the regimen until treatment is completed - is assigned to the private provider or public health department, rather than to the patient. An individualized, patient-centered case management strategy, including initiating DOT at the beginning of TB treatment, is strongly recommended.

For additional information, please contact the MDH TB Prevention and Control Program at 651-201-5414 or www.health.state.mn.us/tb.

4. August is "Submit a Bat for Rabies Testing Month"
Just a reminder that bat exposures constitute a rabies risk; almost all domestically acquired cases of human rabies in the United States are due to bat variants of the virus. You might recall that we had a case of human rabies in 2000 due to a bat bite. Every August we see a very large surge in the number of bats submitted for rabies testing. This is probably due to a combination of factors that increase the likelihood of human-bat contact, i.e., dispersal of immature bats, the beginning stages of migration for migratory bat species, and the process of bats checking out potential winter roosting sites (e.g., houses). Bat bites necessitate rabies postexposure prophylaxis (PEP) (if the bat cannot be tested and shown to be negative for rabies). PEP is also recommended in situations in which a bat bite cannot be reasonably ruled out, such as when a person has physical contact with a bat, a bat is found in a room with a previously unattended child, or a person wakes up to find a bat in the same room. Bat bites cannot always be detected by physical examination. Our telephone (651-201-5414 or 1-877-676-5414) is manned 24 hours a day to provide recommendations for rabies prophylaxis.

5. Legionnaires' Anniversary
On July 21, 1976 over 4,000 persons attended the Pennsylvania Department of the American Legion Convention in Philadelphia. Several attendees became ill with chest pains, fever, and pneumonia within two days after the convention started and the first death occurred on July 27. This was the beginning on an outbreak of unknown etiology in which 221 cases were recorded including 34 deaths. An extensive epidemiologic and laboratory investigation began which ultimately lead to the discovery of the cause of the outbreak by Joseph McDade through his isolation of the Legionella bacteria in early 1977.

In Minnesota, 15 cases of Legionnaires' disease were reported in 2001, 18 in 2002, and 4 to date in 2003.


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 Friday, November 19, 2010 at 02:16PM