November 18, 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
Preliminary Case Investigation
The most common symptoms reported among the cases were diarrhea (95.7%), abdominal pain/cramps (80.9%), nausea (76.6%), and vomiting (72.3%) (Table 1). Dates of symptom onset ranged from May 18th – June 17th and peaked on June 5th with 11 cases. A second peak occurred on June 12th with 6 cases (Figure 2). The epidemic curve is consistent with a point source infection followed by secondary infections. The average duration of illness was 10.74 days (range: 1-27 days).
Of the 47 cases, 15 (31.9%) sought medical attention. Six children were prescribed nitazoxanide as treatment. None required hospitalization. A total of 12 stool samples, all from the Jacksonville team, were collected for testing. Five samples were positive for Cryptosporidium oocysts, six were negative, and one was lost during the testing process.
The risk factor analysis included 105 of the 124 individuals interviewed. Two cases and 17 controls were excluded from the analysis because they did not attend the tournament. The risk factor most strongly associated with illness was staying at Hotel A. The statistical analysis showed that those who stayed at Hotel A were over 30 times more likely to develop illness than those who stayed elsewhere (OR=30.10, 95% CI 6.664-135.956). Sharing a team water cooler, having a team meal, or prior water activity were other risk factors that had a statistically significant association with infection. Other exposures including eating at the concession stand or prior travel did not have an association with illness (Table 2). Further analysis was conducted among those individuals who stayed at Hotel A to consider specific water exposures as risk factors. Of the 68 individuals who stayed at Hotel A, there were 43 cases and 25 controls. Those who swam in the pool were 5.57 times more likely to become ill than those who did not swim in the pool (OR=5.57, 95% CI 1.804-17.203). Despite reports of turbid water coming from the faucets at Hotel A, ingestion of hotel water was not analyzed as a risk factor because 100% of cases and controls used hotel water for drinking or brushing teeth.
Because teammates participated in several common activities before and after the tournament, it is likely that some risk factor associations are due to confounding. Odds ratios adjusted for exposure to these potential confounders are shown in Table 3. Confounding was considered to be present if there was ≥10% difference between crude and adjusted odds ratios. A breakdown of characteristics of swimmers at Hotel A is shown in Table 4.
The average swim time among cases was greater than that of controls on all three days, but the difference was statistically significant on June 2nd only. The proportion of swimmers who recall swallowing water was similar on June 3rd and 4th, but was significantly greater among the cases on June 2nd. The proportion of swimmers who swam underwater was similar among cases and controls for all three days. Assuming that exposure to Cryptosproidium oocysts occurred on June 2nd, the mean incubation period among swimmers who became ill was 5.68 days (range 2-15 days), which is consistent with cryptosporidiosis infection.
Other risk factors that had a statistically significant association with infection were participation in prior water activities, sharing a team meal, and sharing a team water cooler. These associations are a result of confounding and not true associations with infection. The team members associated with this outbreak participated in several events together, and confounded the relationship between exposure to the swimming pool and infection. Many children involved in this outbreak had multiple prior water exposures at multiple locations, but no common source was implicated. Similarly, although there were team meals and shared water coolers, there were no meals or water sources in common between the two ill teams. No specific restaurants or food items were implicated as possible sources of infection.
There were several limitations to this study. First, the investigation did not begin until three weeks after the tournament was held. Many of the cases had already recovered when they were contacted for interview. This was a barrier to obtaining positive stool samples for confirmatory testing. It also led to recall bias. It was difficult for interviewees to provide an accurate food and exposure history. The time lapse also limited the environmental investigation by decreasing the possibility of finding Cryptosporidium oocysts in the pool or water supply at the hotel. Another drawback of this study was that other guests of Hotel A who were not associated with either T-ball team were not contacted. A guest list was provided by the hotel, but there was no contact information available for follow-up. Interviewing other guests at the hotel would have provided a more accurate assessment of exposures. Selection bias was another limitation of this study. Cases were more likely to complete interviews than controls. In addition, controls that did participate may differ in some way from those who did not. This makes the control group for this study less representative of all eligible members of the control population. Finally, the selection of controls was inconsistent. The intent was to interview all players and family members of each team, similar to the way cases were interviewed. It was difficult to carry out this selection because so many controls were unwilling to participate. As a result, only a group of team members were interviewed rather than the entire team.
Effective prevention strategies will also require education of swimmers. Parents should be educated about the transmission of cryptosporidiosis and encouraged to practice strict family hygiene, especially among diaper-aged children. Individuals with diarrhea should refrain from recreational water activities until at least two symptom-free weeks have passed. This is especially important because of the intermittent diarrhea common with Cryptosporidium infection.
Sharleen Traynor is an EIS fellow assigned to the Duval County Health Department in Jacksonville. Kathleen Ward is a biological scientist at the Jacksonville HSE. Dr. Zaheer is the natural sciences manager of the Department of Epidemiology at the Duval CHD and Angela Morgan is the senior community health nurse for epidemiology at the Duval CHD. They can be reached by phone at 904.791.1688.
The Bay Area Professionals in Infection Control (BAPIC) will be holding their annual conference on January 27, 2006 at the Clarion Hotel Tampa Westshore. This year's program, "Old Problems-New Solution" will address topics such as Clostridium difficile, the National Safety Health Network, Infection Control Risk Assessment, zoonotic infections including Avian flu, and hepatitis issues including health care associated outbreaks. The speakers will include national and state leaders in their fields.
This one-day conference will be offering 7.2 contact hours provided by St. Joseph-Baptist Healthcare for nursing and laboratorians. Registration is $70.00 for members and $100.00 for non-members. Hotel reservations must be made by December 26, 2005 to receive the conference rate of $109 a night at the Clarion Hotel, located at 5303 West Kennedy Boulevard in Tampa, Florida. Free parking and free airport courtesy shuttle are also available.
For further information about this program, please contact Diana Doughty at St. Joseph's Hospital at 813. 870.4306.
Bureau of Epidemiology
Grand Rounds Program
The Tuesday, December 27, 2005 program will feature Joann Schulte, DO, MPH, Medical Epidemiologist, CDC assignee to the Bureau of Epidemiology, Florida Department of Health; and Phyllis Yambor, RN, Bureau of Immunizations, Florida Department of Health presenting on Meningococcal Vaccine Safety: Issues in Surveillance and Epidemiology. This presentation will discuss the role of epidemiology in monitoring adverse reactions associated with vaccines and the role of the VAERS system, describe the current investigation of possible adverse events related to the newly licensed conjugate meningococcal vaccines and review recent trends in the meningococcal disease in the US and Florida. One hour of continuing education units will be provided to nursing and laboratorians.
For further information about this program please contact Melanie Black, MSW, professional training coordinator at 850.245.4444, ext. 2448.
No one knows if the current avian influenza will mutate into a form that can be readily transmitted among humans and if there will be little to no immunity. But to prepare our 13 mostly rural counties for that possibility, the North Florida Region Domestic Security Task Force is hosting Pandemic Influenza Workshops to be held in each county. The county health departments and county emergency management share responsibility for inviting county and community leaders. The invitees include responders and hospitals, business leaders, social organizations, local health care agencies, and faith-based groups. Two counties, Lafayette and Suwannee, have already hosted workshops. The remaining counties will be completed by December 17.
The workshop consists of two parts. Part I consists of a presentation on the characteristics of influenza virus, how it is transmitted, lessons from the three 20th Century pandemics -- particularly the deadly 1918 virus -- ways to mitigate influenza virus transmission, and community planning for a pandemic. Three live demonstrations are presented by members of the North Florida Domestic Task Force team: Virus particle transmission using glow-germs and ultraviolet light, proper hand-washing technique, and the proper fit of an N-95 mask. As in the Oprah Winfrey Show, each participants leaves with "prizes" that include a package of tissues, a bar of soap, and an N-95 mask, designed to screen out bacteria and viral particles.
Part II of the workshop is an interactive desktop exercise that incorporates all of the planning issues covered in Part I. The tabletop exercise is presented by the Florida Public Affairs Center of Florida State University who so ably assisted with the popular Beleaguered Bus Exercises. This exercise leads participants through the four phases of an emergency: preparedness, response, recovery and mitigation. During each phase, the participants are asked a series of questions involving potential scenarios using a short timeframe, and their responses, recorded on laptops linked to a wireless server, form the basis for the development of a community pandemic influenza action plan. The leader of each organization is presented a CD ROM with the action plan that they crafted during the exercise.
It is our hope that we won't see a pandemic develop but even if it does not, we firmly hope these workshops will make community leaders more knowledgeable and better prepared to reduce their local contribution to the 36,000 people who die each year in the US from influenza.
Jack Pittman is the health and medical co-chair for Region 2 in Florida. He's also the health preparedness director at the Leon County Health Department. To reach him by phone, call 850.487.3146, ext. 132.
At the request of the CDC, serum samples were collected from Florida hepatitis A cases and sent to the CDC for hepatitis A viral sequencing. The CDC also provided a questionnaire for the cases to be conducted by the various county health departments involved.
The oyster tags collected from the four restaurants showed that the oysters that were likely consumed came from the same harvesting area in Louisiana. Further investigation of the Alabama cases also showed the oysters that were consumed there were also from the same harvesting area. Public notification was not made due to the fact that it was too late for prophylaxis and no oysters remained on the market at that point. Oysters in Florida have a terminal sale date of 14 days from the time of harvest and most of the hepatitis A cases consumed oysters in late July to early August.1 A voluntary recall of the oysters was declared by the Alabama dealer who shipped the Louisiana oysters to Florida and Alabama. In addition, due to Hurricane Katrina, the harvesting areas in Louisiana had already been closed, thereby controlling for any additional sales of contaminated oysters. The FDA Seafood Safety Specialist in Louisiana reported that all of the original dealer’s records were lost due to the impact of the hurricane.
Five of the eight Indian River cases, the St. Lucie County case, and the Polk County case ate raw oysters at the same restaurant in Vero Beach. The restaurant has a 29 cent special on raw oysters every Tuesday night. The restaurant inspection found the oyster shucking area (raw bar) to be dirty and knives used for shucking the oysters were not being properly cleaned. The Dade, Monroe, Pinellas County cases ate raw oysters at the same restaurant in Key West. One Sarasota County case also ate raw oysters at the restaurant in Key West. The Brevard County cases ate raw oysters at a restaurant in Fort Lauderdale. The Lee County case ate oysters at a restaurant in Fort Myer’s Beach.
This multi-state outbreak of hepatitis A was clearly associated with the consumption of contaminated raw oysters either before or during the harvesting process. While it is always possible to get hepatitis A from raw oysters, it is also rare. Reportedly the last event of this type in Florida was in the late 1980’s3. An outbreak of this sort is something that would be more likely seen in an underdeveloped country with poor sanitation. Additional cases were reported from Alabama (17) and later, from Tennessee (6), South Carolina (1) and Ohio (1). An abstract on this multi-state outbreak has been submitted by Stephanie Bialek, who performed the EpiAid for Alabama, to the International Conference on Emerging Infectious Diseases to be held March 19-22, 2006 in Atlanta.4
Reported Cases of Hepatitis A in Florida Attributed to Raw Oyster
1 S. 5L-1.007(g), FAC
2 Bad Bug Book, US Food and Drug Administration, Center for Food Safety and Applied Nutrition, Food Borne Pathogenic Microorganismx and Natural Toxins Handbook, Hepatitis A Virus, http://www.cfsan.fda.gov/~mow/chap31.html, accessed 10/17/05.
3 Epidemiologic Notes and Reports Foodborne Hepatitis A - Alaska, Florida, North Carolina, Washington. MMWR, April 13, 1990/39(14); 228-232.
4 Bialek, Stephanie. Personal communication, email: 11/10/05.
Janet Wamnes is a regional environmental epidemiologist at the Ft. Pierce Bureau of Community Environmental Health in St. Lucie. Roberta Hammond is the waterborne disease coordinator at the Bureau of Community Environmental Health in Tallahassee and can be reached at 850.245.4444, ext. 4116.
Influenza viruses present a continuing challenge as we approach the 2005-2006 influenza season. Each year, anticipation of the annual influenza epidemic produces concerns about vaccine availability, the severity of the season and the potential emergence of new strains. Laboratory-based surveillance plays a critical role in the characterization of circulating influenza strains and early detection of unusual strains and subtypes.
On December 6, 2005, the National Laboratory Training Network will sponsor a one and one-half hour teleconference, entitled Influenza 2005: The Laboratory’s Role in Pandemic Preparedness and Response hosted by Carol Kirk, coordinator of the Virology Program and Laboratory Network and Peter A. Shult, PhD., chief virologist and the director of the Communicable Disease Division and Emergency Laboratory Response at the Wisconsin State Laboratory of Hygiene in Madison, Wisconsin.
This program will provide an overview of the antigenic characteristics of influenza viruses and current laboratory diagnostic methods. The main focus of the presentation will be avian influenza, pandemic preparedness activities, and the laboratory’s critical role in influenza surveillance and pandemic preparedness and response.
This intermediate-level program is designed for clinical and public health laboratorians who perform viral testing. Continuing education credit will be offered to laboratorians based on 1.5 hour of instruction.
There is no fee for this program. Designate a site representative for each location and register online at http://www.nltn.org/courses and select this course from the list of educational and training programs. If you have difficulty with the on-line registration process, please call 617.983.6285. The registration deadline is December 2, 2005. Upon receipt of your registration, confirmation letters with teleconference details will be emailed. Before the teleconference, download handout materials on the day of the teleconference for participants, call the number provided and use on line only per registration site. This allows all of the participants to be joined with the program speakers.
In compliance with the Americans with Disabilities Act, individuals needing special accommodations should notify the NLTN at least two weeks prior to the course. For more information, email firstname.lastname@example.org.
Melanie Black is the professional training coordinator for the Bureau of
Epidemiology at the Florida Department of Health in Tallahassee. To contact
her, call 850.245.4444, ext. 2448.
Alachua, Hillsborough, Nassau and Walton counties are currently under medical advisory for mosquito-borne disease. Pinellas, Pasco, Duval and Marion Counties are currently under a medical alert for mosquito-borne disease.
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 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.
Christie Luce is administrator
of the Surveillance Systems Section in the Bureau of
Epidemiology. She can be reached at 850.245.4444, ext. 2450.
Click here to review the most recent disease figures provided by the Florida Department of Health Bureau of Epidemiology.
D'Juan Harris is a GIS
specialist in the Surveillance Systems Section of the Bureau of
Copyright©2005 State of Florida