Minnesota Department of Health (MDH) Bug Bytes

October 13, 2003
Vol. 4: No. 11

Topics in this Issue:
1. Salmonellosis and Breakfast
2. West Nile Virus Update
3. Students, Calves, and Cryptosporidiosis
4. Autopsies and CJD
5. Upcoming Conferences

1. Salmonellosis and Breakfast
Thanks to the timely reporting of Salmonella cases by laboratorians and ICPs at St. Mary's Medical Center and St. Luke's Hospital, an outbreak of Salmonella Heidelberg cases was identified in St. Louis County. To date, 30 confirmed cases, all of which ate at the same Duluth restaurant during September, have been reported. Most confirmed cases reported eating breakfast items, though no specific food item is associated with illness.

Illness onsets range from September 9 to September 29. Meal dates range from September 4 to September 24. Seven of the cases were hospitalized, with a median duration of hospitalization of 4 days. Fifteen of the cases were female and 15 were male. The median age of cases was 31 years (range, 1 to 77).

St. Louis County Department of Health and MDH staff evaluated the restaurant. Multiple violations had been found during previous inspections in August. These violations were not yet corrected, and inadequate food preparation procedures were identified. Foodworkers were interviewed to determine if any had experienced recent gastrointestinal symptoms. Though none immediately reported illness, all foodworkers were restricted from work and are currently being screened for Salmonella infection. To date, Salmonella has been confirmed in four foodworkers. The restaurant was temporarily closed for equipment repairs, screening of employees, and environmental cleaning.

2. West Nile Virus Update
With the arrival of cold weather and frost, we are now at the end of the mosquito and West Nile virus (WNV) seasons in Minnesota. We continue to receive reports on cases that were ill in late August and early September. To date, 130 confirmed or probable human cases (four fatal) have been reported from 51 counties. These cases include 23 meningitis and 22 encephalitis cases. Eighty-five cases (65% of all cases) had less severe WNV fever only. Sixty persons have been hospitalized. The median age was 45 (range, 4-86) for WNV fever cases, 37 for meningitis cases (range, 2-80), and 74 for encephalitis cases (range, 38-96). Nineteen WNV-infected blood donors have been identified during the year in Minnesota by blood bank screening procedures. Four of these donors went on to develop WNV fever. There have been no transfusion-associated cases reported in the state. Most human WNV case activity has been seen in western and central Minnesota counties.

In addition to human cases, we continue to detect widespread WNV activity in birds (411 laboratory-confirmed birds from 63 counties), and horses (67 horses from 31 counties). We are currently doing viral testing on a large number of mosquitoes that were collected from various locations around the state during the past four months. In the U.S, as of October 8, 6,507 human cases including 136 deaths have been reported from 42 states. Most of the cases continue to be reported from the Great Plains states (especially Colorado, Nebraska, and South Dakota).

3. Students, Calves, and Cryptosporidiosis
Last February, we were notified by a hospital of two cases of cryptosporidiosis in middle school students from different schools. One was hospitalized for two days. Both were students of an animal science class held at an agricultural building as part of a program administered by the school district. Students were bussed to the facility for 1-hour daily classes. Students had direct contact with calves, horses, goats, sheep, and rabbits. We found that one third (31/92) of the students were ill with vomiting or diarrhea. Cryptosporidium parvum was found in seven students and a sibling of a student-case. All isolates were genotype 2 (bovine).

Ten 3-day old calves had been purchased for the class; upon arrival most were ill with diarrhea ("scours"). Human illness was associated with contact with calves. Eight of nine calves tested positive for at least one human pathogen including Cryptosporidium parvum, Giardia, and Campylobacter.

We recommended several preventive measures including assigned sinks for handwashing, supervised handwashing, alcohol-based hand sanitizers, and increased use of coveralls and rubber boots.

In late September, we were notified of two cases of cryptosporidiosis in students participating in this year's animal science program. Again, we investigated and found 46% (37/81) of the students ill with vomiting or diarrhea. Cryptosporidium has been confirmed in numerous students and calves. Many of the recommendations we made last February were not fully or consistently implemented.

CDC has published recommendations on reducing the risk for transmission of enteric pathogens at petting zoos, open farms, animal exhibits, and other venues such as this class (at http://www.cdc.gov/foodborneoutbreaks/
). We have learned through experience that it is not enough just to distribute these guidelines, but we must work with the venue operators to make sure they fully implement the recommendations.

4. Autopsies and CJD
In conjunction with the CDC, we have been involved in national surveillance for Creutzfeldt-Jakob Disease (CJD) since 1996. Surveillance includes ongoing review of vital statistics data for deaths where CJD is indicated as the underlying cause of death. Deaths among persons <55 years of age are of particular importance and are further investigated as possible variant CJD (vCJD)(i.e. the disease that has appeared in the United Kingdom and elsewhere which is related to bovine spongiform encephalopathy or mad cow disease).

Since surveillance relies on death certificate data, an inherent difficulty within the current system is the low number of autopsies performed on patients with suspect CJD. In Minnesota, autopsies are performed on approximately 30% of deaths attributed to CJD. As a result, most cases are never confirmed through postmortem neuropathologic examination of brain tissue. Classifying persons who have died of neurodegenerative diseases will reduce uncertainty regarding the existence of vCJD in the U.S. and the transmissibility of chronic wasting disease (CWD) to humans.

We received CDC funds to increase the number of autopsies by reimbursing for the transport of the body and for the autopsy itself for certain individuals who have died of neurodegenerative diseases. We have contracted with two Minnesota medical centers. They will conduct autopsies and neuropathological examination of brain tissue to confirm a diagnosis of CJD on behalf of institutions that otherwise may not have the resources to perform them.

Autopsies will be considered in cases of progressive dementia in a person <55 years of age and at least two of the following clinical features:

Myoclonus, visual or cerebellar signs, pyramidal/extrapyramidal signs, and akinetic mutism
Typical EEG during an illness of any duration; and/or a positive 14-3-3 CSF assay and a clinical duration to death of <2 years and a routine investigation does not suggest an alternate diagnosis

Autopsies may also be considered for individuals of any age who meet the above criteria (with the exception of age) and have a history of consumption of venison from deer or elk from CWD-endemic areas. The endemic areas include free-ranging deer and elk from northern Colorado, southern Wyoming, and southwestern Nebraska. If an individual presents to you with the criteria described above or there are other unusual case aspects, please call us at (612) 676-5414 to make arrangements. All requests will be evaluated by MDH and referral center personnel.

5. Upcoming Conferences

Packaging and Shipping: A Training Workshop for Clinical Laboratory Staff - Thursday, October 30, 2003, 9:00 am - 12:30 pm, Northwest Medical Center (North Lobby) 120 LaBree Ave. South, Thief River Falls, MN.
Sponsored by MDH, the Minnesota Laboratory System (MLS), and Northwest Medical Center. Free of charge.
To register/more information contact Darlene Kelley at 218-683-4471 or dkelley@nwmc.org.

Chemical Terrorism - Thursday, November 13, 9:30-4:30
Satellite/video broadcast of a National Chemical Terrorism Conference. The morning session will be a satellite broadcast sponsored by the Minnesota, Iowa, and Wisconsin Departments of Health and the National Laboratory Training Network. It will include speakers from the Department of Defense, FBI, the Environmental Protection Agency, and the CDC. The featured speaker will be Dr. Jimmy Valentine, Professor of Pharmacology, University of Arkansas and a nationally recognized expert in chemical terrorism. The afternoon session will include speakers from the MDH, the Minnesota Department of Public Safety Division of Homeland Security and Emergency Management, the Poison Control Center, the 55th Civil Support Team of the National Guard, and the FBI, who will provide a statewide perspective.

In addition to being live in the Twin Cities, the program will be teleconferenced to seven regional locations around the state. Watch the training website http://www.health.state.mn.us/oep/training/
for more details to come.

Emerging Infections - Friday, November 21, 8:00-4:40
9th Annual Emerging Infections in Clinical Practice and Emerging Health Threats Conference, Radisson Hotel Metrodome in Minneapolis. Featured speakers will discuss SARS, foodborne disease, zoonotic disease, immigrant health issues, AIDS, dermatological diseases, bioterrorism preparedness and more. The conference brochure and registration form is also available on-line at: http://www.med.umn.edu/cme/


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Updated Friday, November 19, 2010 at 02:16PM