VIRUS SURVEILLANCE SUMMARY UPDATE
ending November 10, 2001-Week 45
Blackmore, M.S. Vet. Med., Ph.D.
National report: During week 45 (November 4-10, 2001), two
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
4,891 specimens for influenza viruses have been tested and 39 (1%) were
positive. Of the 39 isolates identified, 38 were influenza A viruses and 1 was
an influenza B virus. Fourteen of the influenza A viruses were subtyped, all
were influenza A (H3N2). Influenza A isolates have been identified in Alaska,
Arizona, Florida, Kentucky, Louisiana, New York, Texas and Utah. The influenza B
isolate was identified in Texas. The proportion of patient visits to
sentinel physicians for influenza-like illness (ILI) overall was 1.2%, 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 6.7% during week 45. This percentage is below the epidemic threshold
of 7.2% for this time. Twenty-two state and territorial health departments
(Colorado, Florida, Georgia, Indiana, Kansas, Kentucky, Louisiana, Maine,
Michigan, Missouri, Nebraska, Nevada, New Mexico, New York, North Dakota, Ohio,
Pennsylvania, Tennessee, Texas, Utah, West Virginia, and Wyoming) reported
sporadic influenza activity and 26 reported no influenza activity.
Florida: Data from Florida suggests low levels of
influenza activity. As was reported last week, 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 45.
Influenza-like illness activity was detected in 17 counties from Escambia to
Miami Dade. Higher flu activity than expected for this time of year (>2%) was
reported by physicians in Brevard, Broward, Escambia, Palm Beach and Sarasota
county. No new positive influenza tests were reported this week. Between
September 4 and November 20, influenza A (H2N3) was isolated from 5 patients
residing in Broward, Collier and Palm Beach counties. In addition, positive
rapid antigen tests were reported from Duval County (1), Miami-Dade (4) and
Volusia Counties (2).