Molecular typing and whole genome next generation sequencing of human adenovirus 8 strains recovered from four 2012 outbreaks of keratoconjunctivitis in New York State

Ocular infections caused by human adenovirus (HAdV) are highly contagious. The most severe are usually caused by members of species HAdV-D (types HAdV8, 19, 37, 53, 54, and 56) and can manifest as epidemic keratoconjunctivitis (EKC), often resulting in prolonged impairment of vision. During the early months of 2012, EKC outbreaks occurred in neonatal intensive care units (NICUs) in 3 hospitals in New York State (New York and Suffolk Counties). A total of 32 neonates were affected. For 14 of them, HAdV8 was laboratory-confirmed as the causative agent. Nine healthcare workers were also affected with 3 laboratory-confirmed, HAdV-positive EKC. A fourth EKC outbreak was documented among patients attending a private ophthalmology practice in Ulster County involving a total of 35 cases. Epidemiological linkage between the neonatal intensive care unit outbreaks was demonstrated by molecular typing of virus isolates with restriction enzyme analysis and next generation whole genome sequencing. The strain isolated from the ophthalmology clinic was easily distinguishable from the others by restriction enzyme analysis.