Morbidity of parainfluenza 3 outbreak in preterm infants in a neonatal unit

Parainfluenza type 3 virus (PIV-3) is an important nosocomial pathogen which causes pneumonia and bronchiolitis in infants. We report an outbreak of PIV-3 respiratory infection which occurred in the neonatal unit of KK Hospital in June 2005. This is the second PIV-3 outbreak in our unit after the fi rst in December 1994. The clinical characteristics and outcome of 7 infants tested positive for PIV-3 on nasopharyngeal aspirate in June 2005 were reviewed retrospectively. Seven cases were infected with PIV-3 during this outbreak. The median birthweight of affected infants was 970 g (range, 740 to 2585 g), gestational age was 27 weeks and 4 days (range, 24 to 35 weeks), and postnatal age was 84 days (range, 28 to 250 days). Apnoeas and bradycardias were significant symptoms in 3 infants, 5 infants had progressive respiratory distress while the remaining 2 infants had flu-like illness. Five infants required ventilatory support and there were no deaths. The index case was an infant with chronic lung disease who was on oxygen supplementation and subsequently required ventilatory support with nasal CPAP. Despite implementation of control measures to prevent the spread of infection through early identification with strict cohorting of infected cases, contact tracing/screening, and reinforcement of hand hygiene precautions, the outbreak lasted for 24 days. PIV-3 respiratory infection in preterm infants can present with non-specific symptoms, leading to significant morbidity especially in those with underlying pulmonary pathology. Early recognition of symptoms and diagnosis by physicians, and prompt institution of control measures are necessary to prevent the spread of infection.