Division of Disease Control and Health Protection

For July 7, 1999

We identified 50 people who either attended a church supper on June 23 or had 'take out' from the supper. Forty-nine were interviewed. A total of 17 individuals developed diarrhea 1-7 days after the meal; 8 (47%) developed bloody diarrhea. Other symptoms included nausea (41%), vomiting (12%), fever (18%), headache (18%), abdominal cramps (82%), dizziness (29%), fatigue (53%), and muscle aches (24%). The mean incubation period was 3 days. Seven individuals were hospitalized and they are doing well. Most have been discharged or they will be discharged in the near future. The mean age for confirmed and probable cases was 59, the median was 67.

To date:

1. 2 cases were culture positive for E. coli 0157:H7 at the Florida Public Health Labs.
2. 2. 4 cases were culture positive for E. coli 0157:H7 at Baptist Hospital and those specimens are being sent to the state lab for confirmation.
3. 1 case was EIA positive and culture negative at Baptist Hospital. The specimen tested shiga-toxin positive at New England Medical Center, as part of a study that Baptist Hospital is participating in.

Additional specimens are pending at the state lab and in Biloxi, Miss.

A beef and broccoli entree was the main food item served. None of the food items were statistically associated with the illness, which is not unusual given the limited number of foods served. Attack rates ranged from 32%-48%. The attack rate for the beef and broccoli was 36%. If individuals who had their meal reheated (take out) are excluded from the analyses, the attack rate is 42%. The highest attack rate is for the ice tea (48%), and ice in a drink (48%). Both are unlikely sources.

The church's cook was interviewed about the preparation of the meal. There were several cooling and re-heating steps that were improperly performed. The roast beef comes from a local meat market. It was cooked on the Tuesday before the meal, cooled to room temperature and refrigerated overnight. It was then taken to the meat market and sliced. The meat was reheated at a low temperature prior to service. Rice was prepared the morning of the 23rd (the day of the meal) and allowed to remain on the stove without heat until service at 5pm. that evening. Salad was prepared from bagged precut salad mix from Sam's Wholesale Warehouse. It was not washed prior to service.

The Department of Agriculture and Consumer Services was notified and an inspection of the meat market was conducted. There are separate areas and slicers used for raw and cooked meats. The leftover foods from this meal were kept and served to the children attending the church's daycare center the next day. The roast beef was reheated prior to service. The only item not available to the children from the Wednesday night supper was pudding. There is no food leftover for laboratory testing.

Given the temperature used in the preparation of the beef, the beef is the most likely source. Sixteen of seventeen cases (94%) consumed the beef while only 70-75% consumed the ice tea or had ice in their drinks. The church and day care center both use city water; none of the children in the day care are ill (except one who attended the dinner). Also, since the meal was served in the day care center the following day, and the beef was reheated to the appropriate temperature, it would explain why none of the children are ill. The only statistically significant finding is that individuals who ate dinner earlier (5-5:30) were 3 times more likely to become ill (95% CI 1.03, 9.02, p=.02). We are unsure as to the reason at this time.

No other cases or suspect cases have been identified in the county.

An update on the Salmonellosis-from-orange-juice outbreak is available at the Oregon Health Division website.

Human monocytic ehrlichiosis (HME), a tick-borne disease caused by Ehrlichia chaffeensis, became a notifiable condition in Florida in 1996. Since then, 17 cases have been reported of which 9 were definitively diagnosed. These cases were among people residing in central and northern counties of the state and most were diagnosed during the months of May through July. During 1998, Centers for Disease Control and Prevention (CDC) and Florida Department of Health staff collected ticks from Liberty, Leon and Wakulla counties and have, preliminarily, identified ehrlichial organisms in up to 30% of the ticks (especially Amblyomma americanum - the lone star tick).

The natural history of Ehrlichia chaffeensis has yet to be elucidated. It is not known to what extent common, medium-sized mammals may play in the expansion of the pathogen as reservoir hosts to the vector ticks. To first determine if raccoons could be infected with E. chaffeensis, a convenience sample of raccoon sera (collected during 1998 in Pinellas County for oral rabies vaccine evaluation) was tested at CDC for antibodies to ehrlichia. Nine of 150 (6%) sera reacted to test antigen. To date, no HME cases have been reported from Pinellas or surrounding counties.

During late May 1999, sera from 26 raccoons and opossums collected in Wakulla and Liberty counties were evaluated by CDC. Ten of the 19 (53%) raccoons and 1 of 7 (14%) opossums seroreacted to E. chaffeensis. CDC staff are attempting to isolate the organism from whole blood samples and examine if E. chaffeensis can be identified in ticks collected from all of the 26 animals.

HME is considered an emerging infectious disease and it is likely that the true incidence in people is greater than that reported in the state. Clinicians are encouraged to consider HME among febrile patients with a history of tick exposure. Laboratory criteria for a confirmed case is a four-fold or greater change in antibody titer to Ehrlichia spp. (ideally taken 4 weeks apart), or a positive polymerase chain reaction assay, or intracytoplasmic morulae in blood, bone marrow or CSF with a positive titer. The DOH State Laboratory can conduct serologic testing at no charge to the clinician.

People are encouraged to prevent tick bites by using tick repellants and conducting daily "tick checks" to remove these arthropods as soon as possible.

The attached file lists the human rabies cases in the United States from 1990 through present (a total of 27 reported cases). Two of these deaths occurred in Florida. Both of these human rabies cases were men bitten by rabid dogs (one in Haiti during 1994 and one in Mexico during 1996). However, the majority of the reported cases (N=20) were caused by a bat rabies strain.