Epidemiologic aspects of a St. Louis encephalitis outbreak in Fort Walton Beach, Florida in 1980.

From July 10 through August 4, 1980, five cases of St. Louis encephalitis (SLE) occurred in and near Fort Walton Beach on the Gulf Coast of northwest Florida. These were the first cases of SLE ever reported from the Florida panhandle. To determine the extent of SLE infection in the community, sera (n = 968) were collected from patients at the local hospital and county public health unit and tested for SLE virus antibody. The SLE attack rate was highest in a centrally located impoverished census tract. There was a trend toward decreasing seroprevalence with distance from the central area of the city. Overall, seroprevalence was higher in males (prevalence ratio = 2.7) and in all areas, seroprevalence increased with age. The serosurvey results suggest that SLE has been endemic in the Fort Walton Beach area.

Influenza and pneumococcal pneumonia immunization. Protecting our high risk population.

Pneumonia and influenza (P & I) constitute Florida's sixth leading cause of death. The P & I death rate in 1987, 10.5 per 100,000, was the highest since 1978. Major target groups for one or both vaccines used in prevention, as recommended by the Immunization Practices Advisory Committee (ACIP), include persons with chronic diseases of the heart or lungs, residents of nursing homes and other chronic care facilities, and persons aged 65 and older. Despite well-defined recommendations, vaccine coverage rates in Florida are as low as 30% in persons greater than or equal to 65 years of age. Knowledge and attitude surveys demonstrate that low coverage among various population groups may be due largely to insufficient awareness and/or negative attitudes regarding pneumococcal and influenza vaccines. Conversely, recommendations by physicians and other health care providers are strongly associated with receiving either vaccine. If the incidence of P & I is to decrease substantively in Florida, much wider use of the vaccines must occur. Because so many high-risk patients depend on private physicians for health care, their role is critical to the success of Florida public health strategies to reverse P & I trends.

Syndromes of Vibrio vulnificus infections. Clinical and epidemiologic features in Florida cases, 1981-1987.

STUDY OBJECTIVE: To describe the clinical and epidemiologic features of Vibrio vulnificus infections. DESIGN: Case series based on notifiable disease report forms and patient medical records. SETTING: Cases reported to the Florida Department of Health and Rehabilitative Services from 1981 to 1987. PATIENTS: Sixty-two patients with V. vulnificus infection. MEASUREMENTS AND MAIN RESULTS: The three clinical syndromes found were primary septicemia (38 patients), wound infections (17 patients), and gastrointestinal illness without septicemia or wound infections (7 patients). Mortality rate was highest for patients with primary septicemia (55%; 95% CI, 38 to 71) and intermediate for wound infections (24%; 95% CI, 8 to 51): no deaths occurred in those with gastrointestinal illness. Common characteristics and exposures in patients with these syndromes included recent history of raw oyster consumption for primary septicemia and gastrointestinal illness, liver disease for primary septicemia, and either having a preexisting wound or sustaining a wound in contact with seawater for wound infections. CONCLUSIONS: Clinicians should ask about marine exposures in patients with underlying medical conditions, especially liver disease, who present with unexplained febrile illness, and should start appropriate therapy promptly.

Rocky Mountain spotted fever acquired in Florida, 1973-83.

From 1973 to 1983, 49 Florida residents were reported with confirmed Rocky Mountain spotted fever (RMSF), 25 of whom were considered to have had Florida-acquired disease. Although there was no history of tick exposure for six of these 25 persons, all had contact with dogs or outdoor activities during the incubation period. The tick vectors of RMSF are widely distributed throughout Florida. We conclude that RMSF, although rare in Florida, can be acquired in the state.

Norwalk virus gastroenteritis. An outbreak associated with a cafeteria at a college.

An explosive outbreak of gastrointestinal illness occurred among students and employees at a small college in Florida in November 1980. Common symptoms were diarrhea, nausea, weakness, abdominal cramps, chills, vomiting, and low-grade fever. Cases of illness were identified in 40% of 628 students and 15% of 162 employees who responded to a survey. Among students, there was a sevenfold excess risk associated with eating one or more meals at the campus cafeteria November 3-5 (p much less than 0.001). Tossed salad from one meal was strongly associated with illness (p less than 0.0001). Fecal contamination of the salad was documented, although the source of contamination was not identified. Person-to-person spread could not be demonstrated. Seroconversion to Norwalk antigen occurred in significantly more cases (5/6) than noncases (1/6) (p = 0.04).

St. Louis encephalitis--Florida 1977. Patterns of a widespread outbreak.

From 8 August through 5 December 1977, 110 laboratory-documented cases (78 confirmed, 32 presumptive) of St. Louis encephalitis (SLE) occurred in 20 counties throughout central-south Florida. Most cases were initially identified through an active surveillance system involving repeated contact of hospital infection control officers. This outbreak had three characteristics that are unusual for SLE epidemics in the eastern United States: it lacked an urban focus, a disproportionate number of cases affected young males, and the epidemic period extended into December. There was no significant difference between attack rates for blacks and whites. Males were significantly more often affected than females. Because of the time required for laboratory confirmation of cases, most outbreak control measures were initiated after the outbreak was declining. Reporting of clinically suspected SLE cases to initiate epidemic mosquito control should improve the timeliness of control measures in future outbreaks.

Norwalk virus gastroenteritis following raw oyster consumption.

In January, 1980, six out of 13 persons (46%) attending a party in a small northwest Florida town near the Gulf of Mexico became ill with Norwalk virus gastroenteritis after eating raw oysters. Symptoms experienced by the ill persons were principally nausea (100%), vomiting (83%) and diarrhea (50%) and were of brief duration. The symptom complex and epidemiology of Norwalk virus infection closely resemble the gastrointestinal illness commonly referred to as the 24-hour intestinal flu or "stomach flu." Norwalk virus infection was identified in this outbreak by application of a recently developed sensitive and specific serologic radioimmunoassay. Oysters from the incriminated batch had fecal coliform levels above recommended standards; however, recent studies of oyster-harvesting waters have shown only a weak correlation between fecal coliforms and the presence of enteric viruses. Further studies are needed to determine whether modifications of monitoring modalities for oyster-harvesting waters are needed.

Trends of brucellosis in Florida. An epidemiologic review.

Human brucellosis in Florida is documented for the 47-year period 1928-1975. Of the 936 cases reported in 1930-1975, more than half (505) occurred in the decade 1940-1949. The incidence declined rapidly to an average rate of five cases per year, although there was an increase in 1974 and 1975. The analysis is mainly concerned with the years 1961-1975, since more complete epidemiologic data are available for this period. Cases occurred throughout the year, with the highest incidence being between May and August. White males in the 25-35 and 35-44 deciles were most affected. Of occupations identified between 1963-1975, 44% were related to the livestock-producing industry, 16% to the meat processing industry and 28% to hunters, housewives, students and children. Twelve per cent of the cases did not fall in any of these categories. Cattle were the most probable source of human infection in the livestock industry, and swine were associated with most non-industry cases. In 1963-1975, B. suis was isolated from 10 cases and B. canis from one case; one other isolate was not identified beyond genus. Of the 27 human cases recorded during 1974-1975, 15 (56%) involved swine contact (five livestock industry, four consumers and six hunters), 11 (41%) involved cattle contact (all from the livestock and meat packing industries), and one involved contact (with both cattle and swine (livestock industry). Human cases contracted from swine were scattered statewide, whereas cases associated with cattle only occurred in counties that had )( high densities of cattle and 2) modified-certified ratings in the Brucellosis Eradication Program.