The Bureau of Epidemiology is available 24 hours a day, 7 days a week for consultation at our main number (SunCom 205-4401 or 850/245-4401) PLEASE NOTE: Consultation after 5 p.m. & on weekends is intended for emergencies.

Ursula E. Bauer, PhD, Chronic Disease Epidemiologist

Synthetic estimates are often used to provide local level data when such data are unavailable. Synthetic estimates typically apply the age, sex, and race-specific statewide estimates of a given risk factor or condition to the age, sex, and race distribution of the local area. To the extent that a condition or risk factor is determined or influenced by age, sex, and race, this method may work well. However, for many conditions, these three demographic characteristics are only a part of the explanation for differences in the distribution of risk factors, conditions, or diseases.

In an effort to quantify the magnitude of the difference between synthetic estimates based on state level data and local level estimates based on local level data, we calculated synthetic estimates for seven chronic disease risk factors and conditions using data from Florida's Behavioral Risk Factor Surveillance System (BRFSS). These were compared to local level estimates on data from a cardiovascular health study conducted in five rural North Florida counties, following the state BRFSS methodology.

Actual and synthetic estimates for each of the five counties and each of the seven chronic disease risk factors and conditions are displayed in the table. These data show that synthetic estimates generally underestimate the magnitude of the chronic disease risk factor or condition. In this situation, synthetic estimates are of little value as estimates of the prevalence of these conditions at the local level. Where local level data are required, they will need to be collected.

The Hepatitis and Liver Failure Prevention & Control Program is happy to announce the posting of the Hepatitis Clearinghouse on the INTRANET. The purpose of this clearinghouse is to give county health departments an organized method of viewing hepatitis resources that they can utilize in their own programs. The web-based clearinghouse contains resource listings regarding hepatitis A, B, & C, and other liver-related diseases. It is located on the Bureau of Epidemiology Intranet site:

(Week ending January 27, 2001-Week 4)

Florida: Florida is one of 14 states still reporting low levels of influenza activity. Overall, two percent of 15,868 patients seeking care by reporting physicians in the influenza sentinel surveillance network met the case definition for ILI during week 4. Influenza-like illness activity was detected statewide from Escambia to Miami Dade. Higher flu activity than expected for this time of year (>3%) was reported by physicians in Alachua, Escambia, Pasco and Polk counties. Twelve isolates of influenza were reported to our laboratory database this week: influenza A (H1N1) was isolated from patients in Hillsborough (1), and Leon (1) counties. Influenza A was also detected in specimens collected from patients in Orange (1) and Palm Beach (2) counties. Flu B was reported from Hillsborough (2), Indian River (2), Leon (2) and Santa Rosa (1) counties. Since October 1, 102 influenza isolations have been reported to the state health office: 36 influenza A (H1N1) isolates from Broward, Charlotte, Dade, Duval, Escambia, Indian River, Lake, Leon, Nassau, Orange and Polk counties, one influenza A (H3N2) from Duval county, 14 untyped influenza A isolates from Alachua, Clay, Columbia, Hillsborough, Orange, Palm Beach and Pinellas counties) and 51 influenza B isolates from Brevard, Broward, Charlotte, Clay, Duval, Hillsborough, Indian River, Leon, Levy, Orange, Palm Beach, Santa Rosa, Seminole and Volusia counties.

National report: Influenza activity is increasing nationwide. Thirteen state and territorial health departments reported widespread and 22 states reported regional activity during week 4. Influenza isolates were recovered from twenty-four percent of the 1,949 specimens tested by WHO and NREVSS laboratories. Sixty-seven percent of the isolates were flu A predominating (63-88% of all isolates) during the last three weeks in 6 of the 9 regions. Influenza B has predominated in the Mid-Atlantic (New York, Pennsylvania and New Jersey) and approximately equal numbers of influenza A and influenza B has been reported from the East South Central (Alabama, Kentucky, Mississippi and Tennessee) and Pacific regions.

Of the 244 virus strains that have been antigenically characterized at CDC, all but 59 have been antigenically similar to the vaccine strains. Six A (H1N1) (5%) were similar to A/Bayern/07/95. Although this is a distinct virus, the vaccine induces production of high titers of cross-reactive antibodies to A/ Bayern-like viruses. Fifty-three influenza B strains were more closely related to the B/Sichuan/379/99 strain than to B/Beijing found in the vaccine. B/ Sichuan virus exhibits cross-reactivity with the vaccine strain.

During week 4, the percentage of all deaths due to P&I as reported by the vital statistics offices of 122 U.S. cities was 7.5%, which is below the epidemic threshold of 8.6%

Four percent of patient visits to U.S. sentinel physicians were due to influenza-like illness (ILI). The percentage of patient visits for ILI was above baseline levels (3%) in 7 of 9 surveillance regions.

Respiratory syncytial virus (RSV) activity remains high in central and southwestern Florida where 47.9% and 37.1% of tested specimens were positive for RSV. Nineteen percent of RSV specimens tested in the southeast and 25.6% of specimens tested in northeastern Florida were positive. Twelve hospital laboratories in the state participate in this program.