VIRUS SURVEILLANCE SUMMARY UPDATE
ending October 27, 2001-Week 43
Blackmore, M.S. Vet. Med., Ph.D.
National report: During week 43 (October 21-27, 2001), three
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
3,148 specimens for influenza viruses have been tested and 20 (1%) were
positive. Of the 20 isolates identified, 19 were influenza A viruses and 1 was
an influenza B virus. Nine of the influenza A viruses were subtyped, all were
influenza A (H3N2). Influenza A isolates have been identified in Alaska,
Arizona, Louisiana, New York, and Texas. The influenza B isolate was identified
in Texas. The proportion of patient visits to sentinel physicians for
influenza-like illness (ILI) overall was 1.3%, 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 6.5% during
week 43. This percentage is below the epidemic threshold of 6.9% for this time.
Sixteen state and territorial health departments (California, Florida, Georgia,
Indiana, Kansas, Kentucky, Missouri, Nevada, New Jersey, New Mexico, New York,
Ohio, Pennsylvania, Tennessee, Texas, West Virginia, and Wyoming) reported
sporadic influenza activity and 32 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 43.
Influenza-like illness activity was detected in 18 counties from Duval to Miami
Dade. Higher flu activity than expected for this time of year (>2%) was
reported by physicians in Broward, Escambia, Monroe, Palm Beach and Sarasota
county. Eight positive influenza tests were reported this week. Influenza A,
H3N2 was isolated from a 40-year-old male in Broward County. Positive rapid
antigen tests were reported from Duval County (1), Miami-Dade (4) and Volusia
Counties (2) Between September 4 and October 27, influenza A (H2N3) was isolated
from 4 patients residing in Collier and Palm Beach counties.