Outbreak of Adenovirus D8 in a Neonatal Intensive Care Unit involving multiple simultaneous transmission pathways.

Adenovirus (ADV) outbreaks in neonatal intensive care units (NICU) can lead to durable transmission and serious adverse outcomes. We describe the investigation and control of an ADV-D8 outbreak in a NICU, associated with ophthalmologic equipment used during retinopathy of prematurity (ROP) screening. Cases were observed in neonates, parents and nurses. The outbreak investigation was performed including sampling patients, parents and health care workers as well as the environment for molecular detection of ADV DNA. The investigation was also conducted in the guest house where some parents were temporary residents. A retrospective cohort study focused on neonates hospitalized during the epidemic period to assess the risk associated with ROP examination. We identified 15 cases in neonates; all but one presented with conjunctivitis. Two healthcare workers and 18 parents acquired conjunctivitis. ADV DNA was identified on the RetCam and on the freezer shared by parents. All ADV positive samples were typed as ADV-D8. ADV infections occurred more frequently in neonates who had ROP examinations (37.8% (14/37) vs (0.9% (1/110); P<0.001) (RR 41.6; [5.7-305.8]). The RetCam was disinfected between 2 examinations using a disinfectant that was virucidal on ADV after a 30-min contact. This outbreak was significantly associated with ROP examination with a RetCam that had a disinfection protocol ill-adapted to rapid patient turn-over. In addition, nosocomial transmission via the parents to neonates and parent-to-parent transmission is likely to have played a role in the dissemination of cases. No further case was observed after the new disinfection procedure was enforced.