Although no extensive outbreaks of influenza have been reported
in
the United States this season, states continue to report additional
isolations in association with local influenza outbreaks, and other
states have now reported their first isolations of influenza virus.
The first isolates of influenza virus (all type B) in
Connecticut,
Florida, Illinois, South Carolina, and Vermont were associated with
sporadic cases in these states in early February. In Georgia, the
first isolates of influenza (type B) viruses were collected during
the
first 2 weeks of February from 2 adult patients in Calhoun and from
an
11-year-old boy in the metropolitan Atlanta area. These isolations
occurred at the same time increased school absenteeism was noted
among
students with influenza-like illness in schools in northwest
Georgia
and the Atlanta area. The first influenza type B viruses
identified
in Utah this season were 4 isolates obtained from patients
with onset of illness in late January and early February. Three of
the isolates were from young-adult residents at a church
institution
in Utah County, where a small cluster of influenza cases was
occurring.
During February, the first influenza type A isolates (all H1N1)
reported in New York state and Nevada were from 2 young adults in
New
York City and 1 in Las Vegas.
Influenza outbreaks reported this season have most frequently
been
associated with influenza B virus isolates in schools. The
following
examples from states where influenza isolates have previously been
reported include a typical school outbreak, prolonged activity
involving influenza type B virus without evidence of major
community
impact, and an outbreak with both type A and B virus isolations.
An outbreak of influenza in a parochial elementary school
located
in Cadillac, Michigan, resulted in absenteeism that peaked at 38 of
161 students (24%) on February 9. Influenza type B viruses were
isolated from samples taken on February 8 or 9 from 6 of 9 ill
students and their family members.
In Houston, Texas, influenza type B virus was first isolated in
October 1981, but the frequency of obtaining sporadic isolates
through
physicians and clinics participating in the active viral
surveillance
of the Influenza Research Center began to increase in late December
(1,2). Through February 25, a total of 321 influenza type B and 43
type A(H1N1) isolates had been identified for the 1981-1982 season.
Although some increase in school absenteeism has been observed,
little
evidence of other effects has been reported. Further efforts are
being made to determine the effect of infection in the community.
In the period January 21-February 17, 26 specimens for virus
isolation were collected from students reporting to the infirmary
at
the University of Texas in Austin. Influenza type A virus (H1N1)
was
isolated from 5 specimens, influenza type B from 12, and adenovirus
from 1. Since the beginning of classes in late January, student
health officials have reported an increase from 5 to
40 in the
number of patients seen daily with influenza-like illness.
Reported by D Moore, PhD, G Cooper, MD, State Epidemiologist,
Connecticut Dept of Health Svcs; E Buff, MS, R Gunn, MD, State
Epidemiologist, Florida Dept Health and Rehabilitative Svcs; R
Muldoon, PhD, Cook County Hospital, Chicago, R Harroff, MSc, B
Francis, MD, State Epidemiologist, Illinois State Dept of Public
Health; H Dowda, PhD, R Parker, DVM, State Epidemiologist, South
Carolina Dept of Health; R Vogt, MD, State Epidemiologist, Vermont
Dept Health; C Collier, MD, Calhoun, Georgia, T Munroe, R K Sikes,
DVM, State Epidemiologist, Georgia Dept Human Resources; B Haslam,
F
Urry, PhD, R Johns, Jr, MD, State Epidemiologist, Utah State Dept
Health; M Catalano, MD, I Spigland, MD, Montefiore Hospital, S
Friedman, MD, D Sencer, MD, New York City Health Dept; P
Reichelderfer, PhD, Sunrise Hospital, Las Vegas, J Carr, MD, State
Epidemiologist, Nevada Dept of Human Resources; D Brown, T
Cardinal,
MD, District 1, G Anderson, MD, B Hall, MD, N Hayner, MD, State
Epidemiologist, Michigan Dept of Public Health; P Glezen, MD,
Influenza Research Center, Baylor College of Medicine, Houston, P
Trickett, MD, University of Texas Health Center, Austin, C Sweet,
PhD,
J Taylor, C Webb, Jr, MD, State Epidemiologist, Texas Dept of
Health;
Field Svcs, Epidemiology Program Office, Influenza Br, Viral
Diseases
Div, Center for Infectious Diseases, CDC.
References
CDC. Influenza A--Texas. MMWR 1981;30:566.
CDC. Influenza Update--United States. MMWR 1982;31:73.
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