Indicators of influenza activity are increasing throughout the United States. For the week ending January 23, 1988, 2 states* reported widespread outbreaks of influenzalike activity, and 10 states reported regional influenza-like activity. This is the second week with reports of widespread influenza-like activity. For the report week ending January 16, 1988, physicians reported that 6% of their outpatients were diagnosed as having influenza-like illness. While this level is the highest reported so far this year, it is below the usually observed peak of 10%-12%.

Influenza A(H3N2), the predominant type this season, has now been identified in 25 states (Figure 1). Eight states have reported isolates of influenza A, subtype pending.** Outbreaks of influenza A (H3N2) have now been documented in nursing homes in Minnesota, New York, and Wisconsin. In addition, an outbreak of influenzalike illness began during late December and continued into January in a facility for the mentally handicapped in South Dakota; both residents and staff were affected. South Dakota also reported an abrupt increase in school absenteeism due to influenza-like illness among students and staff. Sporadically occurring cases of Influenza B

*Hawaii and South Dakota.

*Idaho, Kentucky, Mississippi, Missouri, Montana, Nebraska, Texas, Utah, Washington, and Wisconsin.

Reported by approximately 160 physician members of the American Academy of Family Physicians. A patient with a temperature 37.8 °C (100 °F) and at least cough or sore throat was considered to have influenza-like illness.

Arizona, California, Colorado, Florida, Idaho, Iowa, Kansas, Michigan, Minnesota, Missouri,
Montana, New Mexico, New York, North Dakota, Ohio, Oklahoma, Oregon, South Carolina,
South Dakota, Tennessee, Texas, Utah, Washington, Wisconsin, and Wyoming.
**Hawaii, Indiana, Kentucky, Louisiana, Nebraska, Mississippi, North Carolina, and Virginia.

FIGURE 1. States reporting isolates of influenza, by type 19, 1987-January 25, 1988

tt

Update: Influenza Activity - Continued occurring cases of influenza B have been reported from 6 states; however, influenza B has not been associated with any outbreaks.

In the 121 cities reporting regularly to CDC, 5.9% of deaths were associated with pneumonia and influenza (P&I) for the week ending January 16, 1988. This percentage does not exceeded the epidemic thresholds for the influenza season to date (Figure 2).

Reported by: Participating State and Territorial Epidemiologists and State Laboratory Directors. Sentinel Physicians of the American Academy of Family Physicians. WHO Collaborating Laboratories. WHO Collaborating Center for Influenza, Influenza Br, Div of Viral Diseases, Center for Infectious Diseases, CDC.

Reference

1. Lui K-J, Kendal AP. Impact of influenza epidemics on mortality in the United States from October 1972 to May 1985. Am J Public Health 1987;77:712-6.

tt Arizona, Hawaii, Montana, New York, Ohio, and Tennessee.

"The epidemic threshold for the 1987/88 influenza season was estimated at 1.645 standard deviations above the values projected on the basis of a periodic regression model applied to observed P&l deaths for the previous 5-year period, but excluding the observations during influenza outbreaks (1).

FIGURE 2. Pneumonia and influenza deaths as a percentage of total deaths* United States, July 1984 January 16, 1988

Week No. 28 36 44 52 4 12 20 28 36 44

1984

1985

1986

SONDJ FMAMJJA SOND J FMAMJ
NDJ

1987

1988

524 12 20 28 36 44 53 4 12 20 28 36 44 524 12 20 26 Month JASON DJFMAM JJASON DJ FMAMJJA SON OND JFMAM JJASON DJ Year *Reported to CDC from 121 cities in the United States. Pneumonia and influenza deaths include all deaths for which penumonia is listed as a primary or underlying cause or for which influenza is listed on the death certificate.

The Morbidity and Mortality Weekly Report is prepared by the Centers for Disease Control, Atlanta, Georgia, and available on a paid subscription basis from the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402, (202) 783-3238.

The data in this report are provisional, based on weekly reports to CDC by state health departments. The reporting week concludes at close of business on Friday; compiled data on a national basis are officially released to the public on the succeeding Friday. The editor welcomes accounts of interesting cases, outbreaks, environmental hazards, or other public health problems of current interest to health officials. Such reports and any other matters pertaining to editorial or other textual considerations should be addressed to: Editor, Morbidity and Mortality Weekly Report, Centers for Disease Control, Atlanta, Georgia 30333.

Ha CENTERS FOR DISEASE CONTROL

Asia

67 Influenza Update - United States

For the first 26 weeks of 1987, a provisional total of 2,637 measles cases was reported to CDC by 37 states and 5.6% of the nation's 3,138 counties.* This total is 32.7% less than the 3,921 cases reported for the same period in 1986 (1), when 42 states and 9.0% of the counties reported cases. The overall incidence rate for the first half of 1987 was 1.1 cases per 100,000 population; the rate for the first half of 1986 was 1.7/100,000.

Seven states and New York City accounted for 2,148 (81.5%) of the cases reported for the first 26 weeks of 1987: California reported 647; New York City, 414; New Mexico, 303; Texas, 200; Missouri, 178; New Hampshire, 150; Wisconsin, 139; and Illinois, 117. Incidence rates greater than 3.0/100,000 occurred in New Mexico (22.8), Montana (15.6), New Hampshire (13.2), New York City (5.1), Delaware (4.5), Vermont (4.1), and Missouri (3.6).

CDC's Division of Immunization received detailed information on 2,595 (98.4%) of the 2,637 reported cases. Of these, 2,305 (88.8%) met the standard clinical case definition for measles, and 723 (27.9%) were serologically confirmed. The usual seasonal pattern was observed-most cases occurred between March and May (weeks 9 to 19) (Figure 1).

Fifty-seven (2.2%) of the 2,595 cases were known to be imported from other countries; 30 (52.6%) of these cases occurred among U.S. citizens. An additional 74 cases (2.9%) were epidemiologically linked to imported cases within two generations. Forty-six outbreaks (five or more epidemiologically related vases) accounted for 87.6% of all cases. Five outbreaks of more than 100 cases each accounted for 59.2% of all reported cases.

MAR 03.1988

As in 1986, almost 30% of cases involved children under 5 years of age (Table 1). Two hundred twenty-five (30.0%) of the 750 preschool-aged patients were less than 1 year of age; 122 (16.3%) were 12-14 months of age; 32 (4.2%u5.mdsths of bee; and 371 (49.5%), 16 months through 4 years of age. The 15- to 19-year age group also accounted for approximately 30% of the cases and was the only age group for which the incidence rate did not decrease between 1986 and 1987. The groups aged zero to *A provisional total of 3,588 was reported for all of 1987.

*Fever 38.3 °C (101 °F) or higher, if measured; generalized rash lasting 3 more days; and at least one of the following: cough, coryza, or conjunctivitis.

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES/PUBLIC HEALTH SERVICE