EPI UPDATE

The Department of Health has a home on the World Wide Web at http://www.doh.state.fl.us

For information on diseases and conditions of public health importance go to MyFlorida.com, click on Health and Human Services, then Consumers--Diseases and Conditions.

1. Florida West Nile Virus Surveillance Update – 11/29/01

Robin Oliveri, Arbovirus Surveillance Coordinator

The first human case of West Nile virus encephalitis in Marion County has been confirmed in a 52 year old male resident. This brings the total number of cases of West Nile virus encephalitis (confirmed and probable) reported in humans in the State of Florida to eleven. West Nile virus has also been reported in twenty-five birds and sixty-six horses in Marion county.

This patient was hospitalized in October during which time West Nile virus encephalitis was included as a possible diagnosis. The patient has since recovered and is at home. The diagnosis of West Nile virus encephalitis has only recently been laboratory-confirmed.

Despite the fact that this reported illness occurred several weeks ago, the health department wants all citizens to be on a heightened awareness.

To date, eight confirmed human WN cases and three probable human WN cases have been reported. The confirmed cases include a 73-year-old man and a 64-year-old woman from Madison County, a 40-year-old man, residing in Jefferson County, a 73-year-old woman residing in Sarasota County, a 73-year-old woman from Washington county, a 44-year-old man from Duval County, a 45-year-old man from Monroe County and a 74-year-old man from Putnam County. Three probable cases include a 50-year-old man from Monroe County, a 51-year-old man from Marion County and a 36-year-old woman from Leon County.

Three confirmed EEE human cases have been reported. A 9-year-old Okaloosa resident, a 39-year-0ld Levy County resident and an 8-mo-old Leon County resident.

Weekly arbovirus surveillance maps and data summary tables demonstrating dead bird surveillance results, sentinel chicken data and comprehensive arbovirus surveillance data are available through the Bureau of Epidemiology website at the following address: http://www.doh.state.fl.us/Disease_ctrl/epi/htopics/arbo/index.htm , then choose either "surveillance information" or "maps".

Table 1: Summary of West Nile Positive Data as of December 13, 2001, since last summary report on November 28, 2001.

Samuel Crane, MPH, Bureau of Epidemiology

Recently, questions and discussions regarding the effectiveness of ultraviolet light as a germicidal agent against Bacillus anthracis spores have been circulating in response to the bioterrorist attacks on media and government agencies. It is known that microorganisms tend to die or suspend their growth outside their preferred host or environment. However, anthrax spores have been found to be very resistant to heat, sunlight, and other outdoor conditions.

The ultraviolet region (100-400 nanometers) of the light spectrum resides between x-rays and visible light. Ultraviolet light, produced by the sun, is one of the main factors in the death of microbes exposed to outdoor conditions. Studies have shown that the DNA and RNA within the nucleus of a microorganism absorb UV radiation. The UV radiation disrupts the genetic bonds, often killing the microbe and rendering it non-viable or unable to reproduce. Many microorganisms, such as viruses and bacteria have a variable die-off rate when exposed to outdoor conditions, varying from a few seconds to minutes. Typically, the thresholds of time and intensity, specific to each microbe, will kill most, if not all of these microbes when exposed to sunlight. Spore producing microbes and some environmental bacteria have adapted to withstand outdoor conditions and can often survive very harsh environments. As a result of the general knowledge of the activity against microbes, some air conditioning companies are outfitting home and industrial units with UV light systems hoping to purify air and offer protection against bioterrorist agents, such as anthrax and small pox.

The use of Ultraviolet radiation as a germicidal agent has been studied since the 1930’s. Ultraviolet light is known to be an effective germicidal agent at a wavelength of 254 nanometers against a long list of microorganisms, such as E. coli, Salmonella, Staphylococcus aureus, Streptococcus, fecal coliforms, and many others. This wavelength is generally accepted as the gold standard for ultraviolet germicidal irradiation. Although this may be true, little concrete evidence has been established about the effective dose to inactivate or kill anthrax spores. The UV dose is the total amount of energy (measured in Joules, Watts, or Micro Watts) absorbed by the microbe. The dosage is a product of intensity and duration of the UV exposure. The survival curve of anthrax spores, along with the vegetative form of Bacillus anthracis and other microorganisms decrease as light intensity and duration of exposure increase. Standard doses exist for many microorganisms, such as those stated above. Unfortunately, lethal doses for anthrax spores, vary tremendously and a standard value has not been agreed upon. Under research conditions, the vegetative form of B. anthracis is very susceptible to direct UV light and is rendered non-viable within seconds of exposure. However, the spore form has shown extreme resistance to highly concentrated levels of UV light. In 1980, German scientists led a research project to study the effectiveness of UV light on disinfecting surfaces tainted with anthrax spores. Anthrax spores were heat fixed to aluminum, ceramic, and wood surfaces then subsequently exposed to different levels of UV intensity and duration. Under a controlled environment, the scientists reported that over 200,000,000 m w/sec/cm² was not sufficient to completely disinfect all three surfaces. Research from the US Army Medical Research Institute of Infectious Diseases found that a dose of 9,000 m w/sec/cm² for 20 seconds was adequate to kill 99% of the vegetative form of the Sterne strain of Bacillus anthracis streaked on tryptic soy agar. However, the same dose of UV exposure took 25 minutes to kill 99% of the Sterne spores. Without complementing findings among scientists about the effective UV intensity and exposure time, a standard survival fraction which is known for many pathogens, is impossible to ascertain. Currently, available "germicidal" UV light bulbs sold by distributers throughout the US tend to produce between 2,000 and 20,000 m w/sec/cm². According to the studies above, it would take a significant amount of exposure time, using these lights, to produce a sterilization of air or common indoor surfaces.

The difficulty in effectively killing anthrax spores with UV light within a controlled environment leaves much speculation about the possibility and practicality of using UV light within air conditioning systems to protect our homes and workplaces. Even Sylvania, a leading manufacturer of light bulbs and lighting equipment, released a public statement that they are unable to advise on this subject due to lack of scientific evidence. The possibility of anthrax spores being aerosolized and circulated through an office or residential air conditioning system is uncertain. Current hypotheses regarding the mode of transmission for the employees who were infected with anthrax do not support the idea that anthrax spores circulated throughout the air conditioning systems. Even if the postal facilities or media agencies had UV lighting within their air conditioning systems, it likely would not have affected the outcome of the victims.

Kathryn Snavely Teates, MPH, Reportable Disease Manager

The Merlin system published changes in two versions, 1.24 Lead Extended Data and 1.25 Meningitis Extended Data on Tuesday, December 4^th. The publishing of these two new versions represents exciting new developments in the system. The version documents are attached to this article and I have outlined some of the major changes to the system.

Changes

• An error message has been added to appear when any 2016 fields have been left blank after a case has been reported. This will prevent fields from being left blank when updating a case.
• An edit has been added to not allow Extended Data or Case Related Labs to be entered until the case has been saved.
• A new report has been added called Case Management Listing Report, which shows cases by investigator. The report is under a new section in Epi-Analysis called Case Management Reports.
• All resource categories have been merged into two, Provider or Laboratory. This will help control the duplication of resources. The next version contains functionality that will allow the Tallahassee administrator to merge resources and remove duplication.

There are many changes to the system for the lead poisoning extended data screens. This additional functionality has been implemented as a tool for county health departments to use for following lead cases. These screens are not mandatory for all lead poisoning cases but will allow the Childhood Lead Program in the Bureau of Environmental Epidemiology to collect risk and exposure data where possible. Questions about the use of these screens versus the Lead Module can be directed to Susan Limbaugh in the Childhood Lead Program in Tallahassee. A flow chart has been attached to this article to illustrate the structure of the new lead poisoning screens.

• A screen has been added for lead poisoning extended data. This screen covers exposure and risk factor questions. These extended data screens allow additional extended data screens, called Case Follow Up, to be saved for a single case once the original case has been reported to HSDE. For a single lead poisoning case you can have many labs and extended data records. A button at the top of the extended data screen called Case Follow Up takes you to this new feature for the case.
• Recommendations and guidelines have been added to assist with the closing of an extended data Case Follow Up record.
• A new lab result has been added specifically for lead poisoning test. This lab result will print a follow up recommendation based on the numeric value of the blood test. The lab result will also allow entry of follow up appointment date.
• A new section has been added to the Task List to accommodate the case follow up extended data screens and lead poisoning lab results that require follow up. This new section is at the bottom of the Task List and is called Case Follow Up. Any lab that has a future appointment date for follow up results will appear on this new section of the Task List.

A new screen has been added for bacterial meningitis extended data. This screen will take the place of the CDC National Bacterial Meningitis paper form. Counties should keep the paper form for their records but will no longer need to send them to the Bureau of Epidemiology. Meningitis cases will now be reviewed online. The new screen applies to the following ICD9 codes:

• 03600 – Meningitis, Meningococcal
• 32090 – Meningitis, Other Bacterial or Fungal
• 32000 – H. influenzae Meningitis
• 69290 – H. influenzae Cellulitis
• 46430 – H. influenzae Epiglottitis
• 48220 – H. influenzae Pneumonia
• 03841 – H. influenzae Primary Bacteremia
• 71100 – H. influenzae Septic Arthritis
• 32040 – Meningitis, Group B Strep
• 32070 – Meningitis, Listeria monocytogenes
• 32020 – Meningitis, Strep pneumoniae

Thank you for all the comments and contributions that went into publishing these two versions, especially to the pilot counties that helped design the lead poisoning follow up features.

Please contact Kathryn Snavely or the Merlin Helpdesk if you have any questions.

Update 124

Update 125

New Merlin Lead Poisoning Functionality Flow Chart

4. Influenza Virus Surveillance Summary Update

Carina Blackmore, M.S. Vet. Med., Ph.D.

Week ending December 1, 2001-Week 48

National report: During week 48 (November 24-December 1, 2001), 3 specimens tested by the World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories across the United States were positive for influenza. Since September 30, a total of 10,747 specimens for influenza viruses have been tested and 99 (0.9%) were positive. Of the 99 isolates identified, 96 were influenza A viruses and 3 were influenza B viruses. Sixty-five (68%) of the influenza A viruses were subtyped, 64 were influenza A (H3N2) and one was an influenza A (H1N1) virus. Fifty-five (56%) of the influenza A isolates were isolated in Alaska. Influenza A has also been identified in Alabama, Arizona, Colorado, Florida, Hawaii, Kentucky, Louisiana, Minnesota, New York, North Carolina, North Dakota, Pennsylvania, South Carolina, Texas, Utah, Washington and Wisconsin. The influenza B isolates were identified in Louisiana, Michigan and Texas.  The proportion of patient visits to sentinel physicians for influenza-like illness (ILI) overall was 1.4%, which is less than the national baseline of 1.9%. The proportion of deaths attributed to pneumonia and influenza as reported by the vital statistics offices of 122 U.S. cities was 6.4% during week 48. This percentage is below the epidemic threshold of 7.5% for this time. Influenza activity was reported as widespread in Alaska and regional in Arizonaa this week. Sporadic activity was reported from 23 states (Alabama, Colorado, Florida, Georgia, Hawaii, Indiana, Iowa, Kansas, Kentucky, Louisiana, Michigan, Minnesota, Missouri, Nevada, New Mexico, New York, North Carolina, Ohio, South Carolina, Tennessee, Utah, Vermont and West Virginia, 18 states reported no influenza activity.

Florida: Influenza activity remains low in Florida and less than one percent of patients seeking care by physicians in the influenza sentinel surveillance met the case definition for ILI (> 100 F + cough and or sore throat) during week 48. Influenza-like illness activity was detected in 12 counties from Escambia to Monroe. Higher flu activity than expected for this time of year (>2%) was reported by physicians in Duval, Escambia, Monroe, Palm Beach and Polk counties. Six positive influenza A cultures were reported this week. Influenza A (H3N2) was reported from Broward (2), Duval and StJohn’s Counties. Two influenza A isolates of unknown subtype were reported from Pinellas County. Between September 4 and December 7, influenza A (H2N3) was isolated from 9 patients residing in Broward, Collier, Duval, Palm Beach and St John’s Counties and influenza A of unknown subtype, was isolated from 4 patients in Pinellas County. In addition, positive rapid antigen tests were reported from Duval County (1), Marion (2), Miami-Dade (6) Okaloosa (2) and Volusia (2) Counties.

* The column of data representing the "3-year average to week ##" is the average of years 1998, 1999 and 2000 cases to the current listed week (##).