Division of Disease Control and Health Protection

For August 6, 1999

Summer outbreaks of influenza in the United States have been previously documented [1,2]. The Miami-Dade County Health Department recently reported an outbreak of influenza-like illness (ILI) in a state correctional facility [3]. We report on three additional summer outbreaks of ILI in Florida correctional facilities.

On July 21, 1999, the Florida Department of Health (DOH), Bureau of Epidemiology (Central Florida Regional Office) received a phone call from the nursing supervisor of a state correctional facility. Several inmates were experiencing an acute, febrile respiratory illness. The duration of illness was approximately four days and resolved without the use of antibiotics. The illness appeared to be influenza. The Sumter County Health Department was notified immediately. The correctional facility’s nursing supervisor was advised to isolate affected wings, prevent staff from working on multiple wings, exclude ill staff and visitors, and promote hand washing. Isolation was impossible. The majority of inmates are housed in a common dormitory, and they interact frequently in this hall and during recreational periods. Inmates are constantly transferred into and out of this facility.

Influenza vaccination is offered to inmates annually. Staff members, however, do not receive free influenza vaccinations.

For the purposes of this investigation, a case of ILI was defined as an inmate or staff member who had fever plus a sore throat or cough with an onset between July 14 and July 29, 1999. The epidemic curve of ILI in inmates is shown below (see attached Excel file). The gentle up-slope and steep tail indicates person-to-person spread. Between July 14 and July 29, there were 120 cases of ILI identified (115 inmates and 5 medical department staff). The attack rate in inmates was 6.8% (115/1701). The attack rate in medical department staff was 26.3% (5/19). Surveillance was not conducted in the remaining staff members.

Viral culturettes were sent from the DOH Tampa Branch Laboratory to the facility. Six inmates who were acutely ill (onset within last 72 hours) were swabbed, and the samples were received at the Tampa Branch Laboratory on July 27. On August 2, the Laboratory isolated influenza virus from two of the six throat swabs. The isolates were identified as influenza A (H3N2) serotype by a hemagglutination inhibition assay.

In conclusion, influenza should be considered as a potential etiologic agent during summer outbreaks of acute respiratory illness. The influenza A serotype isolated from Correctional Facility A inmates (type H3N2) was the same serotype that was found in an outbreak of ILI in a Dade County correctional facility in late June of 1999 [3]. The source(s) of the outbreaks documented in this report is unknown but may have been this south Florida facility. The continual transfer of inmates from facility to facility provides ample opportunity for transmission of infection throughout the state. The dissemination of ILI in Florida’s state prison system during this summer includes at least two other correctional facilities that have identified ILI in inmates in July and August of 1999.

1. CDC. Influenza A infection – Florida and Tennessee, July – August 1998, and virologic surveillance of influenza, May—August 1998. MMWR, September 18, 1998; 47:756-9.
2. CDC. Outbreak of influenza A infection among travelers – Alaska and the Yukon Territory, May—June 1999. MMWR, July 2, 1999; 48:545,546,555.
3. Cruz M, Trepka MJ, and Katz D. Dade County influenza-like illness outbreak in a correctional facility. Epi Update 1999; July 15. SEE ERATUM IN JULY 23, 1999 ISSUE (Editor’s Corner)

Following an incubation period of 6-20 days, the clinical picture often begins with mild upper respiratory symptoms that progress to an illness characterized by episodes of paroxysmal coughing followed by a characteristic whoop, apnea and post-tussive vomiting. The disease may last 6 to 10 weeks and usually confers immunity. Complications may include pneumonia, otitis media and rarely, seizures, encephalopathy and death. Communicability is high in the early catarrhal stage and continues for 3 weeks following the onset of the paroxysmal cough or for 5 days following treatment. Pertussis is more severe for infants less than one year of age and often requires hospitalization. The at-risk infant often acquires the infection from an older sibling or adult in the household. Pertussis in adolescents and young adults may be due to a waning of immunity from childhood immunization. Pertussis in adults and older children often goes undiagnosed as they may be asymptomatic, have mild symptoms or are treated for the presenting symptoms such as bronchitis without benefit of culture.

Prompt case identification is imperative in order to treat the case and thereby decrease the period of communicability. Contact identification and antimicrobial prophylaxis will further reduce the spread of pertussis. Case confirmation is accomplished by culture with isolation of B. pertussis from a clinical specimen or positive polymerase chain reaction (PCR). The direct immunofluorescent assay (DFA) can provide presumptive diagnosis but is not reliable for lab confirmation.

The following is an example of the communicability of pertussis. Eleven confirmed cases have been reported from one county. These cases occurred in a close-knit extended family, of which many refuse immunizations due to personal religious beliefs. Symptomatic contacts of the first reported culture positive case, an infant, were cultured prior to prophylaxis, and eight of those contacts were culture confirmed.

Immunization against pertussis is the best prevention. Prior to the availability of the pertussis vaccine in the 1940s, pertussis was one of the most common childhood diseases and a major cause of mortality in the United States with over 200,000 cases reported annually. Following the introduction and widespread use of the pertussis vaccine, incidence has decreased more than 98% since 1980; cases now average about 3,700 per year. There is an apparent 3-5 year cycle observed with pertussis, which may explain increases in reported cases in 1992-1993 and 1996. The vaccine, in combination with diphtheria and tetanus, is recommended for children aged 2 months through 6 years. A more purified acellular pertussis vaccine that is associated with decreased adverse events was licensed for the fourth and fifth doses in 1991 and for infants in 1996.

1. National Immunization Program, Centers for Disease Control and Prevention, Council of State and Territorial Epidemiologists, Manual for the Surveillance of Vaccine-Preventable Diseases. September 1997. 8-1.

2. American Public Health Association. Control of Communicable Diseases in Man. Washington D.C., 1995.

Session 3 of the CDC distance learning course entitled "Principles of Epidemiology" (CDC SS3030) will be offered through the Bureau of Epidemiology beginning September 10, 1999. The home-study course is targeted to county health department staff. The course will span three months and will require extensive reading, active participation in a weekly conference call, and a final exam.

Curricula will include concepts, principles, and general methods used in the surveillance and investigation of disease-related events; key features and applications of descriptive and analytic epidemiology; the processes, uses, and evaluation of public health surveillance; and methods of investigating an outbreak.

Professional education credits are offered for the successful completion of this course. The CDC accredits this course for CME’s of 42 hours and CEU’s of 42 hours (4.2 units). Bureau staff will provide guidance and support throughout the course.

Prior sessions of this home-study course were very successful. Thirty participants enrolled in Session 1 and twenty-six (87%) of them passed the final exam. Session 2 had 18 participants enrolled and we expect similar or better test results. Again, we congratulate their fine efforts and thank Local County Health Department Directors/Administrators for their support.

• Sponsorship of CHD Director/Administrator required (E-mail preferred, or memorandum)
• County health department (CHD) staff member performs ongoing epidemiological functions
• Limit of one staff member from each CHD per session
• Maximum enrollment of 16 participants each course offering
• Commitment to attend all audio-conference sessions and complete the final exam

For additional information or registration materials, please contact John Werth, MA.

"The physician has an important relationship to the community. It is his duty to give advice concerning public health matters. He should assist in the enforcement of laws of public health and should be ready to counsel the public on public hygiene and legal medicine, quarantine regulations and the prevention of epidemics and contagious diseases. In cases of epidemics or extreme emergency it is his duty to labor without regard to risk of his own health or life, or concern as to financial returns. For further protection of public health all cases of communicable diseases are required to be reported to the public health authorities. These duties are self explanatory but mean much to society’s welfare.

"The physician should warn the public against various devices which may be injurious to health or may even result in loss of life, and it is further his duty to exert every effort to legally protect the public against such devices. The medical profession of the State of Florida at the last session of the legislature was able to enact such a law, - a law which is of no monetary value to them but is a protection to the public health by requiring all who practice the healing art to have knowledge of the basic sciences.

"These are only a few of the principles involved in the relationship of the physician to himself, the patient and society. As Walt Whitman stated, 'In the end nothing services but personal character' and the underlying basis of all ethics is that one should constantly behave toward others as he desires them to deal with him."