EPI UPDATE

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In this issue:

1. Primary Amebic Meningoencephalitis
2. 2002 Travel Medicine Survey
3. California CD Brief
4. Immunization Update 2002 Satellite Teleconference
5. Bureau of Epidemiology to Conduct "Strategy Sessions"
6. Regional Epidemiology Seminar A Big Success

1. Primary Amebic Meningoencephalitis

Prepared by Steven Wiersma, MD, MPH, Chief, Bureau of Epidemiology

(Update from original work by Bill Bigler, PhD)

July 26, 2002

Primary Amebic Meningoencephalitis (PAM) is a rare disease caused by infection with the ameba Naegleria fowleri. This ameba is commonly found in the environment. It is most commonly found in soil or warm, stagnant bodies of fresh water, such as lakes, rivers, and hot springs, unchlorinated pools, and in discharge or holding basins worldwide.^1,2,3

Infection occurs rarely in humans when the ameba is believed to enter the body through the nose and travel to the brain via the olfactory nerve where it can cause swelling of the brain or linings of the brain. Onset begins abruptly with headache, sometimes with slight upper respiratory inflammation, rapidly progressing to include fever, vomiting, symptoms of meningitis and other central nervous system involvement, followed within a few days by deep coma and death.⁴ Infections usually result in death within 7-10 days of onset.

There are less than 200 cases of disease reported in the world literature and fewer than 20 have been documented in Florida^2,5. Cases are usually reported in children and young adults who have recent exposure to freshwater lakes or streams. The first cases documented in Florida come from Orange County in 1962.⁶ A review of PAM cases in 1990 included 14 Florida cases as of January 1990. Thirteen of 14 cases were in males and the age of cases ranged between 2 and 23 years of age (mean 12 years) with onset between July and October. Bureau records indicate 2 cases during the 1990s. A 14-year-old boy died from PAM in 1997 after swimming at a canal in Orange County. A second fatality from PAM was confirmed in a 19-year-old Palm Beach County boy in 1999. Other sporadic cases may have occurred during the intervening decade, but these cases are not reportable and therefore complete data are not available.

A survey conducted in the early 1970s found that over 46% (12/26) of all lakes surveyed in Florida have the pathogenic ameba and it is believed that more extensive sampling would result in recovery of the ameba from most Florida lakes.⁷ Studies have conclusively shown pathogenic Naegleria to be widely distributed in lake bottom sediment or at the sediment/lake water interface.⁸

Naegleria fowleri is known to thrive in freshwater where the temperature exceeds 86^° F. While studies indicate that chlorination of pools, ponds etc. can destroy cysts and trophozoites of pathogenic Naegleria, there are no practical means of controlling the ameba in lakes and streams.⁹

The following guidelines for prevention appear on the website for the Centers for Disease Control and Prevention (CDC) (www.cdc.gov), however their scientific basis is not established and their ability to change the low incidence of this disease is unclear.

• Do not swim or jump into warm, stagnant, fresh water, such as ponds or warm water discharge pools, or unchlorinated swimming pools.
• Do not swim in polluted water.
• Do not swim in areas posted as "No Swimming."
• Hold your nose, or use nose plugs when jumping or diving into water.

References

1. John DT. Primary amebic meningoencephalitis and the biology of Naegleria fowleri. Annu Rev Microbiol 1982;36:101-23.
2. Visvesvara GS, Stehr-Green JK. Epidemiology of free-living ameba infections. J Protozool 1990 Jul-Aug;37(4):25S-33S.
3. Duma, R. J. et al. Primary amebic meningoencephalitis. N. Eng. J. Med. 1969;281:1315-23.
4. Lubor, C. Amebic meningoencephalitis. In Med. Microbiology of Infectious Diseases, Brause, A.I., Davis, C.E. and Fierer, J (eds) W. B. Saunders Co. 1981;pp. 1281-1284.
5. Viriyavejakul P, Rochanawutanon M, Sirinavin S. Naegleria meningomyeloencephalitis. Southeast Asian J Trop Med Public Health 1997 Mar;28(1):237-40.
6. Butt, C.G.: Primary amebic meningoencephalitis. New Eng. J. Med. 1966;274:1473-6.
7. Wellings, F. M. et al. Pathogenic Naegleria: Distribution in nature EPA Research and Development Bulletin No. 600/1-79-018.
8. Wellings, et al. Isolation and identification of pathogenic Naegleria from Florida lakes. Applied and Environ. Micro. 1977;34:661-667.
9. De Jonckheere, J. et al. Differences in destruction of cysts of pathogenic and nonpathogenic Naegleria and Acanthamoeba by chlorine. Appl. Environ. Microbiol. 1976;31:294-297.

2. 2002 Travel Medicine Survey: Florida Department of Health, Bureau of Epidemiology

Steven Wiersma, MD, MPH, Chief. Bureau of Epidemiology

June 5, 2002

On May 23, 2002 a survey of County Health Departments (CHDs) was conducted to determine the extent and content of CHD involvement in the practice of travel medicine. For the purpose of this survey, travel medicine was defined as the provision of counseling and/or immunizations to prepare clients for travel outside of the United States. All 67 CHDs were sent an email survey and asked to respond by May 30. The survey consisted of 14 total questions. CHDs that did not provide travel medicine services were asked to answer 4 questions and CHDs that did provide services were asked to answer 13 questions.

By June 5, 59 of 67 of CHDs (88%) responded to the survey. Overall, 47.5% of CHDs stated that they provide travel services. When population size of the county was considered, 85% of CHDs with populations greater than 200,000 provide travel medicine services as compared to 28% of CHDs with populations less than 200,000.

Of those CHDs providing travel medicine services, 81% provide immunizations for travelers and 90% provide counseling sessions for travelers. Only 36% of CHDs that provide services allow clients to receive immunizations without counseling services. Counseling that is specific to the traveler’s itinerary is provided by 96% of those respondents providing services.

Many sources of information on current travel medicine risks and guidelines exist. The Centers for Disease Control and Prevention (CDC) travel medicine webpage was used by 75% of respondents that provided services, 4% used another commercial source of information, and 21% used a reference book or other source of information (most commonly a CDC publication).

Those CHDs that offer travel medicine services provide these services on a full-time basis in approximately 50% of cases. The other 50% of respondents indicated a less-than full-time schedule that ranged from 16 hours per month up to full-time.

Of the CHDs that provide services, 18% serve "only local county clients", 39% provide these services "mostly to local county clients", and 43% serve "multiple county clients". Combined responses indicate that 57% of CHDs serve "only" or "mostly" local populations.

For those CHDs that do not provide travel medicine services, 90% of respondents indicated that they would refer clients seeking such services to other CHDs, while 3% would refer to a private clinic, and 6% would refer to another source of service.

When asked if they knew of private clinics or companies in their county that offered travel medicine services to the general public, 75% of CHD respondents indicated they did not and 25% indicated that they did know of such services. Of CHDs that knew of private sources of services, 6 CHDs (43%) knew of one private provider, 3 (21%) knew of 2 providers, 3 (21%) knew of 3, 1 (7%) knew of 4, and 1 (7%) indicated that 80 private providers existed in the county.

Fee schedules for travel medicine services were requested and are available for review.

3. CALIFORNIA CD BRIEF

Report of meeting of 07/24/02 (week 30)

On July 24, 2002, a hospital contacted a local health department for guidance on varicella disease control measures after learning that a hospital employee with varicella had been working in the hospital while he was infectious. The employee worked as a discharge planner in the hospital and participated in a blood bank drive during his infectious period. Employee contacts, patient contacts, and the persons in line with him during the blood drive are being tested. Susceptible hospital employees will be furloughed. The blood bank has been notified and will take appropriate action.

Nosocomial transmission of varicella zoster virus (VZV) is well recognized. Sources for nosocomial exposure of patients and staff have included patients, hospital staff, and visitors who are infected with either varicella or zoster. The Advisory Committee on Immunization Practices (ACIP) and the Hospital Infection Control Practices Advisory Committee (HICPAC) strongly recommend that all health-care workers be vaccinated against, or have documented immunity to, varicella. Although postexposure use of varicella vaccine has potential applications in hospital settings, routine preexposure vaccination of all susceptible health-care workers is the preferred method for preventing transmission of VZV from these workers to patients.

Persons born before 1989 who have reliable histories of clinical varicella are considered immune. Those who do not have such histories should be cons idered susceptible and may be either tested to determine immune status or vaccinated without testing. Because 71%-93% of adults who have negative or uncertain histories are seropositive, serologic testing, before vaccination, may be cost-effective. However, postexposure serologic testing of health-care workers for varicella immunity after receiving two doses of vaccine is not necessary; 99% of persons seroconvert after the second dose.

4. Immunization Update 2002 Satellite Teleconference

Charles Alexander, Chief, Bureau of Immunization

The Department of Health, Bureau of Immunization, in conjunction with the Office of Performance Improvement, is making available the Immunization Update 2002 satellite teleconference through the Department of Health Telnet Videoconference Sites. This live, interactive satellite broadcast will provide the most current information available in the constantly changing field of immunization. The broadcast will be aired on August 15^th from 9:00 a.m. to 11:30 a.m. (EDT) and again from 1:00 p.m. to 3:30 p.m. (EDT).

Anticipated topics include: influenza vaccine, including new recommendations for vaccination of healthy children; the national vaccine shortage situation, hepatitis B vaccine, the recent revision of the Advisory Committee on Immunization Practices (ACIP) General Recommendations on Immunization, smallpox vaccine recommendations, immunization registries, and recent vaccine safety issues. Applicable course materials will be available through this site. Participants may register for either the morning OR the afternoon broadcast on-line at the following site: http://www.phppo.cdc.gov/phtn/imm2002/default.asp#goals. Additional information is available on the Centers for Disease Control and Prevention (CDC) website at www.cdc.gov.

For additional information regarding the program, please contact Tom Bendle of the Bureau of Immunization at (850) 245-4444 ext. 2391 or SunCom 205-4444 ext. 2391.

National Tetanus and Diphtheria (Td) Shortage and Td Seventh Grade Immunization Requirement

Based on information from the vaccine manufacturer, the Centers for Disease Control and Prevention (CDC) anticipates that the supply of tetanus diphtheria (Td) vaccine is now sufficient enough to return to the routine schedule as recommended by the Advisory Committee on Immunization Practices (ACIP). The recommendations can be viewed on the CDC’s website at www.cdc.gov/mmwr/preview/mmwrhtml/mm5124a5.htm. Correspondence regarding return to the routine schedule for Td has been sent to county health departments, Vaccine for Children Program health care providers, and copies will be sent to the medical societies.

5. Bureau of Epidemiology to Conduct "Strategy Sessions"

Don Ward, Deputy Chief, Bureau of Epidemiology

Beginning in August, the Bureau of Epidemiology will convene meetings with county health department staff to elicit their input for planning the bureau’s mid and long range agenda. These day-long meetings will be held regionally throughout the state and will bring together the leadership of the CHDs with the bureau’s senior staff. The domestic preparedness regional structure should be useful in determining appropriate regional attendance. Issues that are expected to be on the agenda include: the bureau’s mission and initiatives, surveillance and epidemiology for bioterrorism, enhancing the capacity of the state’s epidemiology staff, Merlin and EpiCom, needs in chronic disease epidemiology, assignment of EIS staff to CHDs, and others. On August 6, we will begin contacting county health directors and administrators who serve as domestic preparedness regional public health leads. We are looking forward to these meetings and the exciting opportunities they present.

6. Regional Epidemiology Seminar A Big Success

Melanie Black, MSW, Professional Training Coordinator, Bureau of Epidemiology

The Bureau of Epidemiology resumed regional epidemiology training for county health department staff last week in Sarasota. The regional epidemiology seminar, held at Phillippi Estate Park was a big success. Sixty-seven participants (67) from twenty-two (22) counties attended the two-day seminar. Various professions attended; nurses, physicians, epidemiologist, environmental health professionals as well as laboratorians. The evaluation forms completed by the participants indicated they thought this to be a useful and well-presented program.

The seminar provided an overview of epidemiologic principles such as disease reporting, disease surveillance and communicable outbreak investigation. Other topics of interest included, Merlin, Epi Com, chronic disease epidemiology and surveillance, evaluating local surveillance programs, overview of biological agents and laboratory support for epidemiology.

All of us in the Bureau of Epidemiology thank the participants and speakers for making this program such a success and the staff of the Sarasota County Health Department for their assistance with logistical support. We look forward to continuing with this program throughout the state. Planning is underway for the next seminar, which will be held in the panhandle in September. I (Melanie Black) will be managing this activity. If you are interested in hosting one of these training programs or have questions related to this program, please feel free to contact me at (850) 245-4444 ext. 2448 or SunCom 205-4444,ext. 2448.