February 11, 2005

Epi Update Managing Staff:

John A. Agwunobi, MD, MBA, MPH, Secretary, Florida Department of Health
Landis Crockett, MD, MPH, Director, Division of Disease Control
Dian K. Sharma, MS, PhD, Bureau Chief, Bureau of Epidemiology, Editor-in-Chief
Jaime Forth, Managing Editor

"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



Norovirus Outbreak at a Miami-Dade County University
December 2004
by Rodlescia S. Sneed, MPH,
Juan A. Suarez, BS,
Kiren Mitruka, MD,
Stephanie Atherley, RN, MPH,
Edhelene Rico, MPH
                                                              
Background

On December 16, 2004, the Office of Epidemiology and Disease Control (OEDC) of the Miami-Dade County Health Department (MDCHD) received a report from a local university’s Student Health Services that eight students had presented to area hospitals the previous evening with a gastrointestinal illness that included nausea, vomiting, and/or diarrhea. All eight students lived in campus housing, and all ate dinner on December 15 in the same campus dining hall. Ill employees were also identified. This outbreak transpired when the university was not in session and most students were leaving the campus for vacation.

Methods

Epidemiologic Investigation

University officials were advised to obtain stool specimens from ill employees and students, and OEDC advised that ill food handlers be removed from food service activities immediately.

Case finding was initiated with the posting of a questionnaire, developed by Student Health Services, on the university Website. This questionnaire solicited information on demographics, illness history and symptoms, 72-hour food history, and location of food consumption. On December 17, the university sent an email to all residents of the university’s dormitories asking those with and without the GI illness to complete the questionnaire. OEDC staff members later attempted to contact as many students as possible to obtain information that was incomplete on questionnaires. If possible, stool specimens were also collected.

Environmental Investigation

Environmental inspections were initiated in both campus dining halls, in the campus food court and in a campus recreation center with limited food preparation. No food samples were collected, as all food items had been discarded in the facilities. Water samples were collected from water dispensers and from food preparation areas.


Preliminary Control Measures

Food service activities in the dining halls were suspended on December 16. OEDC disease control and prevention personnel recommendations included postponing scheduled catered events or parties, following guidelines for cleaning and sanitization, and monitoring the illness among students and staff. Educational materials on personal hygiene were also provided.

On December 18, in light of several scheduled catered activities at the university during the forthcoming week, the OEDC issued updated food service recommendations. The OEDC recommended that all sit-down catered meals be cancelled. University officials were advised to limit food preparations at the food court, catering only to the football team, which needed to be on campus during vacation. Further, the OEDC advised that only minimal fast food or ready-to-eat items be served at other events. OEDC and Environmental Health staff went to campus to monitor food distribution during these activities.

Laboratory Investigation

Laboratory specimens were submitted to the State Bureau of Laboratories. A total of 35 human stool samples from 15 persons were submitted and tested for bacteria, ova and parasites, and Norovirus. Water samples were tested for coliform organisms.

Case Control Study

A confirmed case was defined as a person who a) ate at least one meal on campus between December 13 and December 16 and subsequently developed either vomiting or diarrhea between December 14 and December 17, and b) had a positive laboratory result for a clinically compatible pathogen linked to the outbreak. Probable cases had meal and illness histories identical to that of confirmed cases but lacked positive laboratory results.

Controls were students without any reported illness who responded to the university’s email request. No employee controls were used in the study, for the initial focus of the investigation was on the magnitude of the student outbreak. Employees only constituted a small fraction of the total outbreak.

Data Analysis

Initially, the analysis of this study focused on food items associated with increased odds of gastrointestinal illness. Given the variety of foods available on campus, the poor food history recall of students, and the inability of OEDC staff to interview most students due to winter vacation, this analysis was not feasible. Instead, data were ascertained of all students’ meal transactions on 12/13 and 12/14 in the two campus dining halls via electronic records of meal swipe cards. We extracted meal history data from the database and conducted a frequency analysis to appreciate any differences in location and time of meal consumption between cases and controls. Statistical analyses were performed using SAS 9.0 and SPSS 10.1.

Results

Statistics of the Outbreak

Of the 219 reportedly ill students, 121 students met the confirmed and probable case definitions; 13 employees met the definitions. Figure 1 reflects the onset dates for confirmed and probable cases. The largest peak in the epidemic curve occurred on December 15, with 92/121 (76%) of all student confirmed and probable cases having onsets on this day.

Environmental Results

No violations were found during the environmental inspection. A rating of “Satisfactory” was given to both dining halls. The inspections did not reveal any obvious environmental condition that could have been associated with the current episodes of gastroenteritis on campus.

Laboratory Results

Eleven of 15 persons tested were positive for Norovirus. Three were students, 7 were food handlers, and 1 was a cleaning staff member. All water samples were negative for coliform organisms.

Case-Control Study Results

Case-control analyses were performed to reflect the known epidemiology of Norovirus. Since the largest peak in the epidemic curve occurred on December 15, meal analyses were performed on meals consumed December 13 and December 14 (both dates are within the 24-48 hour Norovirus incubation period). Sixty-nine controls and 121 cases were included in the study.

Demographic characteristics of the students are shown in Table 1. The most common symptoms among cases were nausea, diarrhea, and vomiting (Table 2). Symptoms lasted between one and three days.

Of the students who completed the questionnaire, most consumed at least one meal in Dining Hall A; very few ate meals in Dining Hall B. Meals consumed in Dining Hall A on both December 13 and 14 showed an association with this outbreak; however, those consumed in Dining Hall B were not associated (Table 3).

Discussion

The epidemic curve of this outbreak suggests a probable point-source exposure to Norovirus, with Dining Hall A being the likely location of exposure. The single large peak gives little evidence for person-to-person transmission. Since food history recall was poor in both cases and controls, it was impossible to identify particular food items linked to the outbreak. As a result, we could not determine whether the outbreak was due directly to a problem in food handling.

Our use of electronic data systems during this outbreak represents a unique approach that could be worthwhile in future investigations. Since the university was not in session during this outbreak, most students had already left the local area. The email request for data and the introduction of an Internet-based questionnaire allowed us to capture data from students that we likely would have missed otherwise. Further, the electronic meal transaction data allowed us to ascertain exposure history when we had no other means. There may have, however, been some trade-off in data quality. Questionnaires completed by a trained interviewer may have produced better food history data. Additionally, selection bias may have occurred in obtaining our cases and controls, as they were identified through their self-report rather than random selection. Finally, it is possible that there were patient cases that became ill due to exposures at other facilities on campus; the availability of electronic meal data was limited to the two dining halls. Despite these limitations, electronic data (if available) could prove useful in investigating large and complex outbreaks when traditional methods are not feasible.

Throughout this investigation, MDCHD provided recommendations to university officials and dining hall administrators to control the outbreak. After Norovirus laboratory confirmation was obtained, the following prevention measures were elicited:

• Ensure that all employees who exhibit gastroenteric or respiratory symptoms are sent home immediately after symptoms have been identified.

• Ill employees should not return to work for a minimum of three days after symptom resolution. If employees come back after three days, strict handwashing protocols should be followed. In addition, employees should not have food handling duties for two weeks after symptom resolution.

• Any food preparation or service areas soiled with vomit should be cleaned using Norovirus decontamination methods.

• In outbreak situations, regular handwashing requirements should be increased during the food handling process.

• In outbreak situations, surfaces should be decontaminated more often with the approved disinfectant at the correct concentration.

Rodelescia Sneed is an EIS fellow assigned to the Miami-Dade County Health Department; Juan Suarez, Kiren Mitruka, Stephanie Atherly and Edhelene Rico are all epidemiologists at the Miami-Dade County Health Department Office of Epidemiology and Disease Control. They can be reached at 305.325.3655.

2004 HIV Testing Results Announced
                                                submitted by Leticia Herandez, MS
 

June 27, 2004 marked the tenth annual National HIV Testing Day (NHTD) sponsored by the National Association of People with AIDS (NAPWA-US) and the Centers for Disease Control and Prevention (CDC). Underscoring the critical role that testing plays in HIV prevention and treatment, last year’s theme was “It’s Better to Know.” Knowing one’s status is essential as early detection of HIV allows for early treatment, which can both prolong and improve the quality of life. Negative results underline the importance of reviewing one’s risk and modifying behaviors in order to decrease the chances of infection. The following is a brief summary of the data collected during the week of NHTD.

Approximately 7,826 tests were conducted during the week (6/21-6/27) of NHTD, 116 of which were positive (1.5%). Of the total tests administered, 39.3% (3,072) were among those who were identified as non-Hispanic blacks and 35.7% (2,795) were among non-Hispanic whites; Hispanics accounted for 21.4% (1,674). Blacks accounted for more than half of the positive tests (52.6%), as compared to whites (27.6%) and Hispanics (18.1%). The positivity rates were 2.0% for blacks, 1.1% for whites, and 1.3% for Hispanics.

Over half of the HIV tests conducted during the NHTD week (4,498) were administered to females. However, males accounted for the majority of the positives (77/116 or 66.4%) yielding a 2.5% positivity rate compared to 0.7% for females. Persons between the ages of 20-29 represented the highest proportion of HIV tests (37.4%) but it was the 40-49 age group who accounted for the highest positivity rate of 3.6%.

A large number of HIV tests were administered to persons who identified heterosexual sex as their highest risk behavior (5,145 or 65.7%); the positivity rate was 0.5%. Men who have sex with men (MSM) and men who have sex with men and use injecting drugs (MSM/IDU) represented 569 tests (7.3%), 38 of which were positive resulting in a 6.7% positivity rate. Persons who had ever been diagnosed with an STD accounted for 466 tests (6%, 2.1% positivity rate), and persons who identified as injecting drug users (IDU) represented 289 tests (3.7%), three of which were positive (1.0%). The figure bellow depicts HIV testing in the weeks surrounding NHTD. A full report is available at http://www.doh.state.fl.us/disease_ctrl/aids/testing/NHTD2004Rpt.pdf

The 2004 NHTD was a success in Florida. This would not have been possible without the collaborative efforts of local health departments, community-based organizations and faith-based organizations.    

                        
Leticia Hernandez is an epidemiologist coordinator at the Florida Department of Health Bureau of HIV in Tallahassee. Also contributing were Guttenberg Pierre, field representative, Joanna Bentley, MPH, incidence coordinator, and Marlene LaLota, MPH, program administrator. All can be reached at the Early Intervention Section at 850.487.9979.

         
Home Sheltering During Hurricane Ivan:
Risk Factors for Exposure to Probable Case
of Meningococcal Disease
                      submitted by Michael Lo, MSPH
 

Background

Hurricane Ivan, the third major hurricane to impact Florida in 2004, made landfall early on the morning of September 16, 2004 on the Alabama coast, with hurricane-force winds extending well into the Florida Panhandle. On September 18, members of the Bureau of Epidemiology’s first Hurricane Ivan Epidemiology Response Team were deployed to the three westernmost counties in the Panhandle hardest hit by Ivan – Escambia, Santa Rosa, and Okaloosa – to assess and assist each county health department’s ability to maintain essential disease surveillance, outbreak investigation, reporting and control functions during the initial disaster recovery process.

As part of these epidemiological response activities in the aftermath of Ivan, the Epi Response Team identified and investigated a probable case of infectious meningococcal disease in a Santa Rosa County resident, and identified contacts for prophylaxis to control a potential outbreak. On September 20, this case was transferred from the emergency department of a Santa Rosa hospital to the pediatric intensive care unit (PICU) of an Escambia County hospital for further management of physical signs and symptoms consistent with meningococcal infection. This was brought to the attention of the Epi Response Team, which immediately began a case and contact investigation in coordination with the Santa Rosa County Health Department (CHD), since a 1½-year-old had just died from meningococcal disease in Escambia County. No epidemiological link was found between the two cases. The investigation revealed the Santa Rosa case had exposed a number of family and unrelated contacts in Santa Rosa County both before and during Hurricane Ivan, as a result of home sheltering with some of these individuals.

Methods

Information on symptoms, date of symptom onset, and diagnosis was gathered from hospital case notes, laboratory reports, and communication with the attending physicians and infection control practitioners at both the Santa Rosa and Escambia hospitals. The custodial parent of the case was contacted by telephone at the Escambia hospital where the patient case had been admitted, and interviewed regarding other individuals who may have been exposed to the case child. The interview focused on the 7 days preceding the child’s onset of illness consistent with Neisseria meningitidis infection. Based on the information given, a line list of potential contacts was developed. These individuals were contacted to verify their exposure history and level of contact with the case. Ceftriaxone chemoprophylaxis was recommended and prescribed to those contacts determined to have been significantly exposed.

Results

The case was a 2½-month-old female infant residing in Santa Rosa County who developed a fever of 102.7ºF on Sept. 17. She subsequently developed a petechial rash on September 18 which appeared on the soles of her feet and progressed upward. Other signs and symptoms observed included drowsiness, purpura and vomiting. On September 19, the case was brought to the emergency department of the Santa Rosa hospital, by which time the rash had progressed to her head. Ceftriaxone was administered intravenously and cerebrospinal fluid (CSF) and blood were subsequently collected for culturing, both of which were negative for N. meningitidis. The patient responded well to this course of treatment. On September 20, she was transferred to the PICU in Escambia County for further management of her condition, which was steadily improving.

The investigation revealed the patient case had periodically attended a home-based day care with multiple attendees in the days just prior to landfall of Hurricane Ivan. During the hurricane’s landfall overnight on September 15–16, this private home sheltered 9 individuals from 3 different families: the homeowner/day care operator, spouse, and child (18 years old); 2 children (5 and 9 years old) from an unrelated family; and the case, her custodial parent, and 2 siblings (4 and 10 years old). The case had also had close contact with her non-custodial parent and the parent’s family during the period of meningococcal disease communicability. A total of 22 immediate and extended family members, acquaintances, and day care attendees were thus potentially exposed and were identified through the contact investigation. On September 22–23, personnel at the Santa Rosa CHD wrote prescriptions for ceftriaxone to be filled at a designated pharmacy for 20 of 21 contacts determined to have been significantly exposed.

One contact on whom the case had reportedly vomited and was thus significantly exposed could not be reached directly after repeated attempts. The Epi Response Team and Santa Rosa CHD communicated their recommendation to the contact’s family that this contact be prophylaxed. On subsequent call attempts, the family informed us that they had consulted their own physician who, contrary to our recommendation, had told them that prophylaxis was not needed for this contact since the case was “not of contagious type”, despite signs and symptoms that were consistent with infectious meningococcal disease.

Discussion

This investigation by the Ivan Epi Response Team in the aftermath of Hurricane Ivan was made more urgent by an unrelated fatal case of meningococcal disease in a 1½-year-old in Escambia County. Although both CSF and blood cultures were negative, the Santa Rosa case demonstrated classic signs and symptoms of infectious meningococcal disease that met the probable case definition of the disease, and prophylaxis of contacts is recommended in such cases as part of routine public health practice. It should be noted that ceftriaxone was administered intravenously more than 2 hours before CSF was drawn from the case, and 5 hours before blood was drawn. Administration of antibiotics prior to collection of specimens lowers the sensitivity of these tests.

Despite the fact that the hurricane had disrupted telecommunications in the impacted area, including the Epi Response Team’s own cellular telephone network, the team was able to reach contacts by placing calls from land-based telephones at the Santa Rosa CHD to a combination of land-based home and cellular telephone numbers provided by individuals interviewed during the course of the investigation. Because the Santa Rosa CHD did not dispense ceftriaxone directly to contacts, it is unknown how many actually had their prescription filled and took the medication as prescribed. However, 20 of 21 contacts identified for prophylaxis either arrived in person or made arrangements to pick up a written prescription from the Santa Rosa CHD on September 22–23, despite challenging road and traffic conditions in the area.

This investigation was notable since it found significant exposures to a probable case of N. meningitidis as a result of home sheltering during a hurricane. In addition, the Santa Rosa CHD itself was operating in a crisis mode in the immediate aftermath of the hurricane, but nevertheless was able to arrange for available staff and resources to effectively carry out this urgent public health intervention during a difficult time. Thus, given the unique challenges of conducting an epidemiological investigation and prophylactic intervention within the context of a major natural disaster, the Ivan Epi Response Team, in coordination with the Santa Rosa CHD, was able to investigate and control a potential outbreak of meningococcal disease, consistent with the stated goals and objectives of the Epi Response Team’s mission.

Michael Lo is a former Florida EIS fellow and an injury epidemiologist with the DOH Office of Injury Prevention in Tallahassee. David Atrubin is a former Florida EIS Fellow and an epidemiologist with Hillsborough CHD. Kim Geib is an ARNP coordinator and PIO for Nassau CHD. Kendra Johnson is a Florida EIS Fellow with Seminole CHD. Aimee Pragle is a regional Florida EIS Fellow based at Nassau CHD. Janet Hamilton is a Florida EIS Fellow with Escambia CHD. Dawn Ginzl is a Florida EIS Fellow with Orange CHD. All were members of the first Ivan Epi Response Team (Sept. 18–24, 2004). Michael Lo an be reached at 850.245.4440, ext. 2729.

The team would like to acknowledge and thank Jim Mills, Dr. Thomas Holland, Lisa Bratten, Sandy Park, and Jan Whitney of the Santa Rosa CHD for actively taking part in this investigation and intervention. We would also like to thank Dr. Joann Schulte and Dr. Pat Ryder for their guidance and involvement in this investigation.


Bureau of Epidemiology Bi-weekly CHD Conference Call Overview
by Jaime Forth

This brief synopsis is provided for those who were not able to join the call during its scheduled time on Friday, January 28, 2005.

Marketing Work group. Christie Luce, EpiCom consultant, reported that an ad hoc work group was formed recently to create a plan that should result in improved services from the bureau. A survey will be circulated soon to gauge the perceptions and expectations of others, and she encouraged recipients to provide candid feedback.

Strategic Plan. Richard Hopkins, assistant chief for science, reported that Tom Belcour is working on the strike team portion of the overall strategic plan.

Florida EIS Program. Julia Gill provided a firsthand account of her experience as a mentor in the program and cited its benefits to host counties seeking experienced epidemiologists. She also emphasized that mentors should be prepared to spend time with the fellow to develop his or her skills.

Applications from host counties or consortiums are due not later than February 25th.

Superbowl Surveillance. Saad Zaheer spoke from Duvall County stating that the EIS Program had provided two EIS fellows to support activities. In addition, two cruise ships would be on standby to provide support. The CDC's BioDefend system would collect data and the EARS system would be in use. Both system are being used as a method of comparing data. He emphasized that it's important not to rely only on electronic surveillance because human intelligence provides valuable observations.

Legionellosis in Hillsborough County. Kelly Granger outlined the case of a 60 year old female with no history of lung disease who had worked in the research wing of a local hospital and reported with complaints of breathing difficulty to one hospital, but died enroute to another hospital before her condition could be stabilized. Shortly afterwards, her husband visited the hospital and tested positive for legionella. He reported that he had used the hot tub in the couple's home although his deceased wife had not. Consequently, the hospital building where his wife had worked was closed by order of the hospital administration, and OSHA became involved.

The next conference call between county health department epidemiology practitioners and staff at the Bureau of Epidemiology is scheduled for Friday, January 11, 2005 at 10:00 a.m. Calls fall on alternate Fridays. For more information about this activity or to place an item on the agenda, contact Melanie Black, MSW, professional planning coordinator, at 850.234.4444, ext. 2448 or via email at Melanie_Black@doh.state.fl.us

Jaime Forth is managing editor of Epi Update. She can be reached at 850.245.4444, ext. 2440.

     

           This Week on EpiCom
                                                          by Pete Garner
 

• For information concerning Avian influenza testing prior to travel, check the CDC Health Notification Forum
• Suspected Norovirus outbreak at assisted living facility in Broward County
• Possible infant botulism case in Orange County
• Hepatitis A on a cruise ship docked in Brevard County

Pete Garner is administrator of the Bureau of Epidemiology Surveillance Systems Section in
Tallahassee.  He can be reached at 850.245.4444, ext. 2481.

Bureau of Community Environmental Health
Seeks Arbovirus Surveillance Coordinator

An anticipated vacancy in the Zoonotic and Vector-borne Disease Program at the Bureau of Community Environmental Health has lead administrators there to begin seeking epidemiologists to fill the Florida arbovirus surveillance coordinator position.

The coordinator manages the Florida Department of Health human and animal arbovirus surveillance activities, analyzes data, distributes reports to Florida surveillance partners and the CDC, maintains the program Website and, with the state public health veterinarian, directs program planning and grant management activities. He or she delivers training programs and presents data in written reports and orally at statewide and national meetings. The coordinator supervises two part-time arbovirus surveillance assistants.

In addition, the coordinator has opportunities to assist with other Zoonotic Disease Program activities as well as epidemiological studies of a non-infectious nature such as pesticide poisoning. The candidate should be an epidemiologist with an MPH or MSPH degree or equivalent and/or experience with arbovirus or other disease surveillance activities.

Interested candidates should direct inquires to Dr. Carina Blackmore at 850.245.4732 or via email at Carina_Blackmore@doh.state.fl.us. The position title is Environmental Scientist II, SES.

Mosquito-borne Disease Update  January 30- February 5, 2005
 Samantha Rivers, MS; Caroline Collins, BS; Kristen Payne;
                   Calvin DeSouza; Carina Blackmore, DVM, PhD 

Weekly Update: During the period January 30-February 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 for Florida.

West Nile (WN) virus activity: Two seroconversions were confirmed in sentinel chickens from Orange and Walton counties.

Eastern Equine Encephalomyelitis (EEE) virus activity: One live wild bird out of 12 captured in Washington County tested positive for EEE. It is not known precisely when this bird became exposed to EEE.

St. Louis Encephalitis (SLE) virus activity: None yet this year.

Highlands J (HJ) Virus activity: None yet this year.

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. Yet others are experiencing unseasonably warm weather favorable to mosquitoes. 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: www.MyFloridaEH.com  The Disease Outbreak Information Hotline offers recorded updates on medical alerts status and surveillance at 888.880.5782. 

                         Weekly Disease Table
                                                                      by D'Juan Harris, MSP

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 Epidemiology.
He can be reached at 850.245.4444, ext. 2435.

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