Correspondence: Norovirus

Studies on norovirus are limited as it cannot be cultured in the laboratory. Surrogate viruses are used in laboratory testing, however there is considerable debate about this practice. Studies show that viruses similar to norovirus, notably feline calicivirus, are not reduced as readily by alcohol hand rubs as they are by hand washing. Later studies using hand rubs containing higher concentrations of alcohol and involving longer contact times have shown an improvement in effectiveness.

There are several difficulties when attempting to prevent the transmission of infectious gastroenteritis:

• Identifying the particular causative agent is not always possible when dealing with cases/outbreaks of gastroenteritis.
• Norovirus is highly infectious and meticulous hand washing and drying is required to have optimal effect in reducing transmission. Exclusive hand washing and drying is not practical in many settings.
• The environment is commonly contaminated so hand hygiene after environmental contact is important

Infection control guidelines advocate the use of alcohol based hand rubs in outbreaks, because in a practical setting they do help to prevent transmission. Alcohol rubs are contraindicated if hands are soiled with organic material.

Compliance is better with hand rubs than it is with meticulous hand washing and drying. So although hand rubs are not as potent in the laboratory as we might like, they are important in the practical setting when used in combination with hand washing and drying.

ACKNOWLEDGMENT Thank you for Dr Rosemary Ikram, Clinical Microbiologist, MedLab South for providing feedback on this question.