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Current Trends Update: Influenza Activity -- United States and Worldwide, 1990

Influenza activity in the United States is monitored by CDC through surveillance systems developed in cooperation with state and local health departments; in addition, CDC receives reports of worldwide influenza activity from international World Health Organization (WHO) collaborating laboratories and WHO, Geneva. This report summarizes influenza activity in the United States and worldwide for April through November 1990. United States

Sporadic cases of influenza were reported to CDC from April through September 1990. Influenza B was isolated from patients in Connecticut, New York, Oregon, and Pennsylvania; influenza A(H1N1), from patients in Alaska and California; and influenza A(H3N2), from a patient in Wisconsin.

During October (when active surveillance in the United States began), sporadic isolates of all three influenza types were reported from patients with respiratory illness: influenza type B in North Carolina and Texas; type A(H1N1) in Texas; and type A(H3N2) in Puerto Rico. During November, influenza B was isolated from patients in Massachusetts, New Jersey, New York, and Pennsylvania, and influenza type A(H3N2), from patients in New Jersey and New York. Isolates submitted to CDC are being further characterized.

During November, no outbreaks of influenza were reported in the United States; however, 13 states (Alabama, Hawaii, Kentucky, Massachusetts, Minnesota, New Hampshire, New York, North Carolina, Ohio, Rhode Island, Texas, Vermont, and West Virginia) and the District of Columbia reported sporadic occurrences of influenza-like illness. In addition, sentinel family-practice physicians from 42 states reported that from 3.5% to 3.7% of patient visits (i.e., nonepidemic levels) were for evaluation of influenza-like illnesses. Worldwide

Since July 1990, all three influenza virus types have been isolated. Countries in the southern hemisphere reported generally low influenza-activity levels during their winter season epidemic period (June-September).

Oceania. New Zealand reported small outbreaks of influenza A(H3N2) in July and August and sporadic cases in October. During this period, Australia reported both influenza A(H3N2) and B activity.

Asia. Hong Kong reported sporadic influenza A(H1N1) and B activity during September and October. Influenza B was isolated in China during October and November.

Central/South America. Trinidad and Tobago reported influenza B activity in October. Brazil, Chile, and Panama reported influenza B activity during July and August.

Europe. Italy reported two cases of influenza A(H1N1) in November. The United Kingdom reported one case of influenza B in October. Finland reported influenza A (untyped) in November, and Czechoslovakia reported an influenza A (untyped) isolate in October and influenza B in October and November.

Canada. Alberta reported localized outbreaks of influenza B in November. Reported by: State and territorial health department epidemiologists and state laboratory directors. WHO Collaborating Laboratories. Sentinel Physicians of the American Academy of Family Practice. Epidemiology Office and Influenza Br, Div of Viral and Rickettsial Diseases, Center for Infectious Diseases; Statistics and Surveillance Br, Div of Surveillance and Epidemiology, Epidemiology Program Office, CDC.

Editorial Note

Editorial Note: Early season reports suggest that both influenza A and B will circulate this influenza season. Amantadine may be used in conjunction with immunization for prevention and control of influenza A (1); however, it is not effective against influenza B. Continued culturing of patients with influenza-like illness is needed to identify areas where influenza viruses are circulating and to determine specific types/subtypes. Information, updated weekly, is available by telephone (CDC Voice Information System (influenza update) (404) 332-4555), through the CDC Information Service on the Public Health Network electronic bulletin board, and by periodic updates in the MMWR. More detailed information on local influenza activity is available from state or local health departments.


  1. ACIP. Prevention and control of influenza: recommendations of the Immunization Practices Advisory Committee (ACIP). MMWR 1990;39(no. RR-7):9-12.

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