March 11, 2005
Epi Update Managing Staff:
"The reason for collecting, analyzing and disseminating information on a disease is to control that disease. Collection and analysis should not be allowed to consume resources if action does not follow."
Foege WH., International Journal of Epidemiology 1976; 5:29-37
A list of the email addresses for the 150 members and 60 persons representing vendors were provided to the SJCHD by the association. Case finding was initiated on January 25 with an email sent to each addressee requesting they contact the St. Johns County Health Department. A second email was sent to non-respondents. Questionnaires were administered by telephone to the seventy-three attendees who responded to the email.
A case was defined as any attendee of the conference experiencing three or more episodes of vomiting and/or diarrhea and/or any three of the following symptoms: nausea, low-grade fever, cramps, headache, chills or fatigue between January 20 and January 27, 2005. Fifteen respondents met the case definition.
Figure 1: Number of Reported Cases by Date and Time of Illness Onset (N = 15)
Table 1: Frequency of Symptoms, (n=15)
Table 2: Number of Attendees by Thursday Lunch Consumption
Odds Ratio = 9.41p-value= 0.0003
Table 3: Type of Product and Menu Item Eaten at Thursday Lunch at Restaurant A (n= 29)
* Analysis of RTE and Cooked Products includes menu items listed in Table 3.
The Florida Department of Business and Professional Regulation (DBPR) conducted an inspection of the resort food service facilities as well as the local restaurant where a luncheon was held on January 25 and conducted sanitation and employee hygiene training on January 27. A joint meeting with SJCHD staff, the regional environmental epidemiologist, DBPR and resort management staff was also held on January 27 to discuss the investigation and provide appropriate information for management of ill employees and /or guests. Statistical analysis of the data obtained from the interviews was conducted using EpiInfo 2000.
Statistical analysis of data showed a risk association of illness with consumption of the Thursday, January 20 luncheon at the local restaurant (OR = 9.41, p-value = 0.0003; Table 2). Meals consumed at the resort or other restaurants showed no significant risk for illness.
Three stool samples were collected and analyzed for bacterial and viral pathogens. Results of the laboratory analysis of the stool samples showed that two of the three were positive for G2 Norovirus and negative for bacterial pathogens.
There were also several reports of secondary cases of gastroenteritis among family members of ill persons as well as illness among some of their coworkers who did not attend the conference.
Point source outbreaks of Norovirus are typically associated with contaminated foods, particularly ready-to-eat items. Such contamination is the result of poor hygiene and inadequate hand washing by infected food workers.
Management staff of the implicated restaurant reported no employees having or complaining of gastrointestinal illness during that time, although there was discussion about a worker with an ill child. The source of the contamination is unknown.
Norovirus particles are very hardy, resistant to chlorine and can remain viable outside of the human host for weeks. Proper hand washing after toilet use is the best method for preventing food borne Norovirus infection. Hand washing is especially critical prior to preparation of foods.
Food service workers who are ill with gastrointestinal symptoms must be restricted from duties during illness. Norovirus can continue to be shed fecally for up to 22 days after infection; therefore, ill workers must be restricted from food preparation and serving duties for at least 72-96 hours after cessation of symptoms.
Aimee Pragle is an epidemic intelligence fellow at the Northeast Florida Consortium and can be reached in Nassau County at 904.548.1800. Kathleen Ward, RS, MSEH; Michael Towle, RS; George Sigman; and Gayle Bush, RN were also contributors to this article.
A policy advising health care givers of the need to contact the state Division of Disease Control prior to conducting tests for avian flu has been released this week. The document, promulgated by Dr. Joann Schulte, medical epidemiologist at the Bureau of Epidemiology and others on her investigative team, also provides guidance on preparation of specimens for virus isolation and other key elements of an investigation into an avian respiratory illness.
The document, posted at http://www.doh.state.fl.us/disease_ctrl/epi/htopics/BirdFlu.htm, presents a series of questions which should be asked of potential patients cases. In addition to verifying the patient's place of domicile, whether they have been hospitalized and the name of the admitting physician, clinicians are directed to learn the patient's recent travel history or whether he has been exposed to someone recently returned from SE Asia; whether there was contact with farm animals in that country; and whether there was an outbreak of influenza-like illness at any place the patient has recently visited. A complete list of questions is posted at the website.
Specific instructions for collection and shipping of specimens to state laboratories in Jacksonville and Tampa, and a PowerPoint presentation on the etiology and epidemiology of avian influenza are also posted on the website. In addition, links to the CDC and World Health Organization are provided. For more details or consultation, contact the on-call epidemiologist at 850.245.4444, ext. 4401.
Jaime Forth is managing editor of Epi Update and can be reached at 850.245.4444, ext. 2440.
Matt Laidler is an epidemic intelligence fellow in Sarasota, Florida. He can be reached at 941.861.2916.
The Bureau of Epidemiology encourages
Epi Update readers to not only register on the EpiCom system at
https://www.epicomfl.net but to sign up for features such as automatic
notification of certain events
contribute appropriate public health observations related
any suspicious or unusual occurrences or circumstances. EpiCom is the primary method of communication
between the Bureau of Epidemiology and other state medical agencies during emergency situations.
Pete Garner is
administrator of the Bureau of Epidemiology Surveillance Systems
Weekly Update: During the period February 27 - March 5, 2005, the following arboviral activities (St. Louis encephalitis (SLE) virus, eastern equine encephalomyelitis (EEE) virus, Highlands J (HJ) virus, West Nile (WN) virus and dengue virus) were recorded in Florida.
WN virus activity: Three seroconversions to WN were confirmed in sentinel chickens from Pinellas and N. Walton Counties this week.
EEE virus activity: Two seroconversions to EEE were confirmed in sentinel chickens from St. Johns County this week.
SLE virus activity: None yet this year.
HJ virus activity:
None this week.
There are no counties currently under medical alert for mosquito-borne disease. Cooler weather in many parts of the state is helping to reduce mosquito populations. Where mosquitoes are present, people are urged to take precautions against getting bitten.
Dead birds should be reported to www.wildflorida.org/bird/. See the web page for more information at www.MyFloridaEH.com. The Disease Outbreak Information Hotline offers recorded updates on medical alerts status and surveillance at 888.880.5782.
The arbovirus surveillance program is staffed by the Division of Environmental Health and can be reached at 850.245.4299.