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INFLUENZA
VIRUS SURVEILLANCE SUMMARY UPDATE
Week
ending November 9, 2002-Week 45
Carina
Blackmore, M.S. Vet. Med., Ph.D.
Florida:
During week 45
(November 3-9, 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 low
0.98%. Higher flu activity than expected for this time of year (>2%)
was reported by physicians in Duval, Okaloosa and Polk counties. The third
positive rapid flu test was reported from Miami-Dade County this week. Earlier
this season an influenza A(H1N1) outbreak was confirmed in Holmes County.
National
report:
One influenza B virus
isolation was made from 738 specimens tested by the World Health Organization
(WHO) and National Respiratory and Enteric Virus Surveillance
System (NREVSS) collaborating laboratories this week. Since September 29, 0.2% (n=11)
of the 6,493 specimens tested nationwide have been positive. Influenza A
activity has been detected in Florida, Louisiana, New York, North Carolina and
South Carolina. Influenza B isolates have been identified in New York, North
Carolina and South Carolina. CDC has characterized one influenza A (H1N2)
isolate antigenically. Both the hemagglutinin (H) and neuraminidase (N) proteins
of this reassorted strain are similar to H and N proteins in the vaccine
strains. The proportion of patient visits to sentinel physicians for
influenza-like illness (ILI) was 1.3% nationwide, which is below the national
baseline of 1.9%. AN ILI outbreak was reported from Louisiana. Sporadic
influenza activity was reported from 17 states (Alabama, Colorado, Florida,
Georgia, Indiana, Kansas, Kentucky, Maine, Missouri, Nebraska, Nevada, New
Mexico, Pennsylvania, Tennessee, Texas, West Virginia and Wyoming). 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 45. This percentage is
below the epidemic threshold of 7.2% for this time.
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