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Current Trends Influenza Update -- United States

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.


  1. CDC. Influenza A--Texas. MMWR 1981;30:566.

  2. CDC. Influenza Update--United States. MMWR 1982;31:73.

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