Minnesota Department of Health (MDH) Bug Bytes
July 6, 2004
Vol. 5: No. 6
1. West Nile Virus Returns
During 2003, Minnesota was on the eastern edge of a large West Nile virus (WNV) outbreak in the Great Plains states. Most of the 9,858 cases, including 262 deaths, occurred in Colorado, Nebraska, North Dakota, South Dakota, Texas, and Wyoming. Minnesota had 148 cases including 4 deaths. The virus was reported in humans, birds, horses, and/or mosquitoes in all but seven counties in Minnesota.
WNV transmission season is just getting underway in the U.S. with low numbers of reports of WNV-positive birds, mosquitoes, and horses from 30 states. Fifty-seven human cases have been reported from 30 states, including 38 from Arizona; there has been one death. Last week we reported our first positive birds (10 crows and blue jays) from five Twin Cities area counties. As in past years, we still expect the greatest risk to humans to be from mid-July through mid-September. updated Minnesota map
We are currently receiving many reports of Lyme disease and anaplasmosis in patients who have spent time in wooded or brushy parts of east-central and southeastern Minnesota during the past two months. WNV testing had been requested or performed on several of these patients. However, again, WNV risks are higher in late summer, and in the past more cases have occurred in western or central Minnesota, outside of the primary tick-borne disease risk area.
Priority for WNV Clinical Testing at MDH Public Health Laboratory:
We are encouraging the submission of serum and/or CSF for arbovirus testing, but are concentrating testing efforts and resources on patients who meet any of the following criteria:
- presumptive viral encephalitis/meningo-encephalitis or aseptic meningitis
- fever and headache that warrants a lumbar puncture and/or hospitalization
- presumed Guillain-Barre syndrome or acute flaccid paralysis
We do not have the resources to test potential mild cases, i.e., those that have headache, fever, chills, or rash, but do NOT require a lumbar puncture and/or hospitalization. Please see the CDC website for further Clinical Guidance: http://www.cdc.gov/ncidod/dvbid/westnile/clinical_guidance.htm
Physicians should call us at 651-201-5414 or 1-877-676-5414, to report suspect cases of WNV. The MDH Laboratory conducts serology (IgM and IgG EIA) for WNV, and IFA testing for LaCrosse encephalitis, Eastern equine encephalitis, Western equine encephalitis, and St. Louis encephalitis. In addition, Vero cell culture is also performed which can detect these agents and other viral agents of encephalitis.
2. Bad Spas
This is the time of the year when we begin to see waterborne outbreaks, typically associated with gastrointestinal illness. However, outbreaks associated with spas occur year round, typically associated with rash or respiratory illness. Last week's (July 2) MMWR (at: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5325a2.htm) reported on a study of municipal inspections of spas, including inspections in Minnesota. In approximately one half of the 5,209 inspections reviewed, one or more maintenance violations were noted. Eleven percent of the inspections resulted in immediate closing of the spas. Additional information for swimmers, pool/spa operators, and health professionals on recreational water illnesses is at http://www.cdc.gov/healthyswimming.
3. Memorable Graduation
On June 9, our laboratory received and confirmed three isolates of Salmonella Agona. We interviewed the three case-patients associated with these isolates and identified a graduation party held on May 29 in a private home as a common source. Approximately 150 to 200 individuals attended the party; the hosting family prepared the majority of the food items, however some food items were brought by guests.
We interviewed guests to obtain information on consumption of foods/beverages and illness history. A case was defined as an attendee of the graduation party who subsequently became ill with vomiting or diarrhea (³3 loose stools in 24-hour period). Of the 61 individuals interviewed, 24 (39%) met the case definition. All 24 reported diarrhea, 17 (71%) had cramps, 11 (46%) reported fever, 2 (8%) had vomiting, and 1 of 23 (4%) had bloody stools. The median incubation period, calculated from the mealtime on May 29, was 33 hours (range, 1 to 144 hours). The median duration of illness was 90 hours (range, 24 to 189 hours). Six case-patients in total were confirmed as having Salmonella Agona, all with an indistinguishable PFGE pattern.
Consumption of hot turkey sandwiches was significantly associated with illness (22/23 cases vs. 21/34 controls; odds ratio, 14.2; 95% confidence interval, 1.7 to 118.4; p=0.004). When three cases, which may have represent secondary cases, were removed from the analysis the relationship between turkey sandwiches and illness became stronger.
Cooked turkey was thawed eight days before the party; mushroom soup was added the day before the party, and the mixture put on a warmer (thus serving as a bacterial incubator in our opinion). Two of three leftover turkey samples, including one untouched during the party, tested positive for Salmonella Agona (PFGE results are pending).
4. Birth of a Public Health Pioneer
On July 1, 1818, Ignaz Semmelweis was born in Buda, Hungary. After becoming a physician and serving in Vienna, he asserted that deaths from puerperal fever (an infection following childbirth) could be reduced by making doctors and medical students wash their hands in a disinfectant solution before entering the maternity ward. In 1861, he published The Etiology, the Concept, and the Prophylaxis of Childbed Fever. Since this was before the discovery and proof of the germ theory, his observations were largely ignored during his lifetime.
5. Mark Your Calendars for Emerging Infections
We are pleased to announce that once again we will be co-sponsoring along with the University of Minnesota Division of Infectious Diseases and International Medicine, and the Center for Infectious Disease Research and Policy, the 10th Emerging Infections in Clinical Practice and Emerging Health Threats Conference. The conference will be held Friday, November 12 in Minneapolis. The agenda is still being finalized but topics will include healthcare associated infections, travel medicine, pneumonia, infections in the blood supply, viral hepatitis, and new developments in antibiotics.
Dr. Karen Kiang, our current Epidemic Intelligence Service officer from the U.S. Centers for Disease Control and Prevention, is leaving us after two years of service. We will miss her and her excellent work and contributions to Minnesota. We wish her well in her continued medical training in Australia.
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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