The possibility of human adenovirus detection from the conjunctiva in asymptomatic cases during nosocomial infection.

Purpose: To prevent outbreaks of nosocomial adenoviral conjunctivitis, proper management for transmission control must be performed. We collected conjunctival samples from asymptomatic inpatients and an ophthalmologist in an ophthalmology ward and attempted to detect the human adenovirus (HAdV) pathogen for infection control.

Methods: One inpatient was diagnosed with adenoviral conjunctivitis on the basis of typical, acute, and severe symptoms and virologic testing by using an immunochromatography (IC) kit. To survey nosocomial infection, conjunctival swabs from 17 other inpatients and 1 ophthalmologist without obvious symptoms of adenoviral conjunctivitis were sampled and analyzed for HAdV pathogens with an IC kit, viral isolation, nested polymerase chain reaction (PCR), and real-time PCR.

Results: HAdV antigens and DNA were detected from 1 and 8 of the 18 samples collected for nosocomial survey by IC kit and nested PCR method, respectively. Moreover, infectious HAdV was isolated in the cell culture from only 1 antigen-positive sample. All PCR-positive samples had identical nucleotide sequences of the partial hexon gene and were determined to be HAdV type 37 by phylogenetic analysis. No inpatients tested showed any symptoms of typical adenoviral conjunctivitis, but slight conjunctival infection caused by postoperative reaction and/or mild conjunctivitis that did not resemble HAdV infection was observed. No one developed typical adenoviral conjunctivitis over the 2-month follow-up.

Conclusions: The clinical course of adenoviral conjunctivitis varies from inapparent infection to severe conjunctivitis. Mild or inapparent HAdV conjunctival infection could be common during conjunctivitis outbreaks and might play a role in the spread of nosocomial adenoviral conjunctivitis.