Norwalk-like virus outbreak in Canberra: implications for infection control in aged care facilities.

This paper reports on an outbreak of viral gastroenteritis in three institutions (two aged care facilities and one hospital) in Canberra during the winter of 2002. Norwalk-like virus genotype II was detected in samples from staff and/or residents in all three institutions. A case series investigation was conducted amongst both staff and residents. It is likely that the outbreaks in the three institutions were linked due to transfers of infected residents from one institution to another, early in the outbreak. A total of 281 cases were identified during the outbreak, which lasted 32 days. Attack rates in the three institutions were 46.3 per cent, 52.7 per cent and 55.2 per cent respectively. Person-to-person spread and/or airborne transmission were postulated as modes of transmission in all three institutions. Infection control practices in each of the aged care institutions were of an acceptable standard for accreditation, but were inadequate to control further spread of the outbreak within and between institutions. Outbreak management plans should be a part of the infection control standards for accreditation of aged care facilities.