|Bureau of Epidemiology|
|Bureau of Epidemiology||May 2001||Utah Department of Health|
Surveillance for the 2000-2001 Season
Salmonella virchow For the First Time In Utah
Monthly Morbidity Summary
Surveillance for the 2000-2001 Season
the virus type(s) associated with influenza morbidity and define the
beginning and end of the influenza season, the Bureau of Epidemiology
conducts surveillance each influenza season. Confirmed influenza
is the category used in Utahs morbidity reporting system to
record cases of influenza that are laboratory confirmed by either
a DFA test or culture. Reported cases of influenza identified by a
rapid test in a physicians office were recorded as probable
influenza. Reported cases of upper respiratory illnesses that were
not laboratory tested, were recorded separately as influenza-like-illnesses.
Viral respiratory diseases generally dominate this category, with
the majority of illness due to influenza, parainfluenza, respiratory
syncytial virus and adenoviruses. Symptoms associated with influenza
and influenza-like illnesses include fever of 101 degrees
or greater, malaise, chills, sore throat, myalgia, cough and coryza.
Severity of illness varies, depending on a patients age and
Surveillance for the 2000-2001 influenza season began the week of October 9, 2000, and continued weekly through April 30, 2001. Surveillance participants included physicians offices, clinics, and university health centers. Also, various schools and school districts throughout the state reported the number of students absent per week during the surveillance period.
There were 129 laboratory confirmed cases reported during the 2000-2001 surveillance season, which is an increase over last seasons 96 cases. The first case was reported on October 16, amid concerns over the influenza vaccine shipment delay. It was reported nearly a month earlier than the first reported case during the 1999-2000 season. Influenza activity peaked the week ending January 27, 2001 nearly a month later than the peak last season. Cases continued to be reported through mid-April. Of the 129 cases, 93 were type B and 36 were type A. Five type A cases were further sub-typed by the Utah Public Health Laboratory and four were the H3N2 strain and one was the H1N1 strain. The Utah cases differed from the national trend of predominantly type A, H1N1 strain. Eighty-five of the reported confirmed cases in Utah were under 18 years of age, and only 4 were over 50 years of age. There were two influenza related deaths reported this year, both were pediatric patients with underlying health conditions.
Weekly rates of absenteeism among participating schools were calculated using student enrollment numbers and number of school days per week. A slight increase in absenteeism was seen during the week of the Thanksgiving holiday but the rates remained fairly consistent throughout the rest of the surveillance period. Similar to last season, absenteeism did not have the same increases that were seen in influenza-like illnesses reported by physicians.
Surveillance was enhanced this season by a partnership between the Bureau of Epidemiology and graduate students in the Department of Family and Preventive Medicine at the University of Utah. The students used a statistical package called statistical process control limits to analyze data on daily patient loads of clinics located throughout the state. They also provided supplies and arranged for couriers for participating clinics to collect clinical specimens on their patients. In the past, one of the biggest barriers for physicians in testing their patients has been the inability to transport specimens to the Utah Public Health Laboratory. Through the Universitys project, even rural surveillance sites successfully submitted specimens. For more information on the Universitys project, please contact the Department of Family and Preventive Medicine at (801) 581-7234.
We wish to thank the following participants in the influenza surveillance project:
Drs. Barton Avery and Gary Harris (Summit Clinic)
Salmonella virchow For the First Time in Utah
Salmonella is an ongoing problem in food safety and public health. It is estimated that from 2 to 4 million cases of salmonellosis occur in the U.S. annually. Gastroenteritis caused by Salmonella is characterized by abdominal cramps, diarrhea, nausea, vomiting, fever and headache. Most of the time, the patient recovers in 1 to 2 days, however, it can cause more serious symptoms. Foodnet data from the Centers for Disease Control and Prevention (CDC) suggest that between 800,000 to 4,000,000 nontyphoidal Salmonella infections occur each year in the United States, resulting in an estimated 18,000 hospitalizations and 500 deaths.
In the past two years, the majority of outbreak associated Salmonella cases in Utah have been identified as Salmonella enteritidis (SE). In 1999, there were three separate outbreaks of SE associated with consumption of home made ice cream prepared with raw eggs. Several other outbreaks of SE were also linked to eggs. In addition to the SE outbreaks, Utah has also seen cases of Salmonella muenchen associated with alfalfa sprouts and Salmonella typhimurium associated with unpasteurized orange juice. There have been outbreaks throughout the country of various types of Salmonella including Salmonella kottbus associated with alfalfa sprouts, Salmonella saintpaul associated with mangoes and Salmonella poona associated with cantaloupe.
The month of February 2001 brought the discovery of a type of Salmonella never before seen in the state of Utah. The Bureau of Epidemiology was notified by the State Microbiology Lab of two cases of Salmonella virchow in a two week period. Since this type of Salmonella is new to Utah, the investigation began. Upon initial investigation, there did not appear to be a link since one case was from Salt Lake County and one was from Duchesne County. Upon further investigation, it was discovered that the Duchesne County resident had traveled to Salt Lake and had eaten at one of the same restaurants as the Salt Lake County case. County food inspectors conducted an investigation of the restaurant, which serves fast food including burgers, fries and shakes, and found no major food safety violations. Nearly a month later, a third case of S. virchow appeared on the scene and the same restaurant was reported in the food history.
At this point, county food safety staff returned to the restaurant to conduct further interviews with food handlers and to collect stool samples for testing. Of twenty-eight food handlers who were interviewed and submitted stool samples, one tested positive for S. virchow. Initially it was thought that this could be the source of the outbreak, but the onset date of the food handler was similar to the other cases and there was no history of travel. The food handlers symptoms cleared within a few days so a physician was not seen. The positive culture was obtained on March 31, 2001, six weeks after the illness and no symptoms were reported at the time of the lab test. After the organism was identified, the food handler was excluded from work until two negative specimens were obtained. One more case of S. virchow has been identified, bringing the total cases in 2001 to five. The fifth case had an onset date of March 31, 2001. Despite persistent efforts by Salt Lake Valley Health Department, no common exposure with the outbreak cases was identified. (Figure 1)
According to FDA, S. virchow is commonly associated with a variety of sources, including tuna, catfish, shrimp, snake heads and frog legs. The Centers for Disease Control and Prevention has record of two outbreaks of S. virchow between 1973 and 1997. A 1973 outbreak in Maryland was associated with a restaurant exposure to beef or veal. Twenty-four illnesses were reported. Missouri reported an outbreak of S. virchow in 1998 involving exposure in a private home to several food sources including BBQ beef, shrimp and crab. Thirty-eight cases reported illness associated with the outbreak. As Salmonella outbreaks from varying sources continue to pose a public health problem, rapid identification and investigation of cases is the key to prevention.
For further information on food safety and prevention of Salmonella and other food borne diseases, FDA provides excellent information and resources on their website: www.cfsan.fda.gov.
Figure 1. 2001 Utah Salmonella virchow Cases
of Health, Bureau of Epidemiology
The Epidemiology Newsletter is published monthly by the Utah Department of Health, Division of Epidemiology and Laboratory Services, Bureau of Epidemiology, to disseminate epidemiologic information to the health care professional and the general public.
Send comments to: The Bureau of Epidemiology, Box 142104, Salt Lake City, UT 84114-2104, or call (801) 538-6191
Approval 8000008: Appropriation 3705
Rod Betit, Executive Director, Utah Department of