|
INFLUENZA
VIRUS SURVEILLANCE SUMMARY UPDATE
Week
ending December 28, 2002-Week 52
Carina
Blackmore, M.S. Vet. Med., Ph.D.
Florida: During week 52 (December 22-28, 2002) influenza
activity, calculated based on the proportion of patients with influenza-like
illness (ILI) seeking care by physicians participating in the Florida Sentinel
Physicians Surveillance Network was 2.3% which is higher than the
national baseline of 1.9%. Higher flu activity than expected for
this time of year (>2%) was reported by physicians in Duval, Leon, Monroe,
Okaloosa, Orange, Palm Beach and Polk counties. Influenza A (H1N1) was reported
from Leon, Okaloosa and Seminole counties this week. Influenza A of unknown
subtype was reported from Brevard and Duval counties and the fourth influenza B
was reported from St Johns County. Positive rapid tests were reported from
Miami-Dade and Pinellas counties. Earlier this season, influenza A (H1N1)
viruses were detected in Broward, Holmes, Indian River Lake and Leon counties,
influenza A (H3N2) in Indian River County and influenza B in Leon County.
Positive rapid tests have been reported from Bay, Broward, Duval and Miami-Dade
counties.
National report: Eighteen isolates (5 influenza A and 13 influenza B viruses) were made from 924 specimens
tested by the World Health Organization (WHO) and National Respiratory and Enteric Virus
Surveillance System (NREVSS) collaborating laboratories this week. Since September 29, 1.3%
(n=273) of the 21,685 specimens tested nationwide have been positive. Nineteen
(25%) of the 75 influenza A viruses have been subtyped; 14 were influenza A H1
viruses and 5 were influenza A (H3N2). Influenza A activity has been detected in
Florida, Hawaii, Louisiana, Massachusetts, Missouri, Nebraska, New Jersey, New
York, North Carolina, Oregon, South Carolina, North Dakota, Texas, Virginia,
Washington and Wisconsin. Influenza B isolates have been identified in Arkansas,
Arizona, Indiana, Louisiana, Missouri, Nebraska, Nevada, New York, North
Carolina, Oklahoma, South Carolina and Texas. CDC has characterized four
influenza A (H1N1), one influenza A (H1N2), two influenza A (H3N2) and 17
influenza B isolates antigenically. All strains were similar antigenically to
corresponding vaccine strains. The proportion of patient visits to sentinel
physicians for influenza-like illness (ILI) was 1.3% nationwide. The State and
Territorial Epidemiologists reported widespread flu activity in Texas. Outbreaks
were reported from Kansas, Oklahoma, Tennessee, Texas and Virginia. Sporadic
influenza activity was reported from 22 states. The proportion of deaths
attributed to pneumonia and influenza as reported by the vital statistics
offices of 122 U.S. cities was 7.4% during week 52. This percentage is
below the epidemic threshold of 7.9% for this time.
|
