Nosocomial Adenovirus Infections: Molecular Epidemiology of an Outbreak Due to Adenovirus 3a

An immunocompromised woman died of disseminated infection due to adenovirus type 3. During her hospitalization and after her death, 38 hospital personnel developed an acute respiratory illness. Adenovirus type 3 infection was documented by culture in 18 of the 38 individuals and by seroconversion in one additional employee. Four of 34 asymptomatic hospital personnel exposed to the index case also seroconverted. Thus, 23 personnel were considered to have confirmed infections, and 22 of these 23 reported direct contact with the index case. Acquisition of infection was associated with the number and type of contacts. Protection against infection was associated with detectable serum-neutralizing antibody in the early serological sample. Restriction enzyme analysis using six different endonucleases indicated that all isolates of virus were type 3a and had identical genetic composition. This study underscores the importance of adenovirus as a cause of nosocomial infection and indicates that genetic analysis of viral DNA is a powerful tool for studying common-source outbreaks.