Minnesota Department of Health (MDH) Bug Bytes
April 30, 2001
Vol. 2: No. 9
1. West Nile Virus: All Quiet On The Western Front (So Far)
2. Legionnaires' Disease
3. FoodNet Data
4. National Hepatitis Awareness Month
5. Antibiogram 2000
1. West Nile Virus: All Quiet On The Western Front (So Far)
West Nile virus (WNV) has caused quite a stir in the eastern U.S.
since it was first detected in New York City during August 1999. This
mosquito-borne virus spread to 12 eastern states last year, causing
a large epizootic in wild birds (especially crows). Most human infections
are asymptomatic or mild, but 83 cases (9 fatal) of West Nile encephalitis
have been reported since 1999. As WNV may eventually make it to Minnesota,
we are conducting the following efforts:
- Dead bird surveillance in cooperation with the Department of Natural Resources and others that would detect bird die-offs (most sensitive indicator of virus presence)
- Human case surveillance: we encourage the prompt reporting of suspect arboviral encephalitis cases. The Public Health Laboratory is prepared to test serum and CSF for all arboviruses of importance, including WNV
- Equine case surveillance: we are working with the Minnesota Board of Animal Health to encourage reporting of encephalitis (and submission of samples to our laboratory) in horses
- Mosquito surveillance: we are working with the Metropolitan Mosquito Control District to monitor local mosquito population levels, and conduct WNV testing on mosquito samples
2. Legionnaires' Disease In the last month we have
been working with a hospital that has seen two cases of possible hospital-acquired
Legionnaires' disease. According to 1997 CDC Guidelines for Prevention
of Nosocomial Pneumonia (http://www.cdc.gov/epo/mmwr/preview/
mmwrhtml/00045365.htm Attention: Non-MDH link)
an epidemiologic investigation should be initiated when there is a definite
or two or more (over six months) possible hospital-acquired cases of Legionnaires'
disease. After the first case was seen, physicians were asked to order
Legionella cultures and urine antigen tests for pneumonia patients
with compatible symptoms. A retrospective review of charts was conducted,
and the hot water system was sampled at ten different sites at this facility.
Legionella pneumophila serogroup 1 was found in five samples. As
a result, the hospital began remediation efforts including hot water tank
superheating, water system hyperchlorination, and installation of a copper-silver
ionization water treatment system.
3. FoodNet Data
FoodNet is part of the Emerging Infections Program conducted by MDH and
seven other states (California, Connecticut, Georgia, Maryland, New York,
Oregon, and Tennessee) representing 29.5 million people in the U.S. Surveillance
for nine foodborne pathogens is conducted. Preliminary data for 2000 was
just released (http://www.cdc.gov/mmwr/preview/
mmwrhtml/mm5013a1.htm Attention: Non-MDH link).
Campylobacter was the most common reported infection followed by
Salmonella and Shigella. There was wide variation by site;
for example, Minnesota had the highest rates of shigellosis, cryptosporidiosis,
and E. coli O157:H7 and lowest rates of yersiniosis and listeriosis.
Speculating on the reasons for these differences keeps your mind active
while commuting to work. Since 1996 when complete data collection began,
there also has been widespread annual variation in incidence. In general,
incidence has remained stable and there has been relative constancy in
the order of pathogen frequency. Data are being used to track progress
in federal efforts to improve food safety (safer meat, poultry, eggs,
produce). Therefore, your efforts as ICPs, clinicians, and laboratorians
in our surveillance system represent extremely valuable information for
the country as a whole..
4. National Hepatitis Awareness Month
May is National Hepatitis Awareness month. Check out our new hepatitis
web page at http://www.health.state.mn.us/hepatitis.
Included are ACIP recommendations for occupational exposure to hepatitis.
We welcome your comments as we continue to expand the information
on the web page.
5. Antibiogram 2000
The MDH antibiogram is a compilation of antimicrobial susceptibilities
of selected pathogens submitted to the Public Health Laboratory during
2000; we have just released the data for 2000 (at the MDH Antibiogram
Web Page; laminated copies are available on request).
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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