Influenza occurs every winter in the United States, its geographic distribution and incidence depending on several factors, including major antigenic shifts in the virus and the susceptibility of the population affected. The winter of 1974 was characterized by widespread outbreaks of influenza В in midwinter during the months of January and February, followed by the appearance in March and April of localized outbreaks of influenza A in various parts of the country, especially the east and west coasts and Puerto Rico.
There have been isolated reports of nosocomial outbreaks of influenza in the United States and elsewhere, with severe and unusual symptoms occurring in debilitated patients suffering from underlying chronic diseases, such as rheumatic heart disease, and in children with congenital malformations. This report describes an outbreak of acute respiratory tract illness in eight female patients in a 27-bed ward during the first week of March 1974, and a single community-acquired case of lethal infection with influenza A in a healthy man.
Materials and Methods
Epidemiologic Study of Wards
The Infection Control Committee daily searched the charts on each of the hospital floors for occurrence of fever. Each case was investigated if fever had occurred after admission to the hospital. Cultures of sputum and blood were taken, and an x-ray film of the chest was obtained.
Study of the Employees
The records of the Employee Health Service and reports of absenteeism by hospital employees were reviewed, and nurses and other paramedical personnel on the wards were questioned. Records of the emergency room and the medical clinics were reviewed in reference to the prevalence of upper respiratory tract infections and pneumonias.
Viral Isolation and Serologic Studies
Throat and nasal swabs and samples of blood for complement fixation and hemagglutination tests were collected and transported to the New Jersey State Department of Health. The methods used for these procedures were those described by Lenette and Schmidt.
All patients with fever and influenza-like illness were isolated on a separate ward.