Epidemiology and Infection

A school outbreak of Norwalk-like virus: evidence for airborne transmission

P. J. MARKS a1c1, I. B. VIPOND a2, F. M. REGAN a3, K. WEDGWOOD a4, R. E. FEY a4 and E. O. CAUL a2
a1 Division of Epidemiology and Public Health, University of Nottingham, Queens Medical Centre, Nottingham NG7 2UH
a2 Bristol Public Health Laboratory, Myrtle Road, Kingsdown, Bristol B52 8EL
a3 Environmental Services Division, Derby City Council, Celtic House, Heritage Gate, Friary street, Derby DE1 1QK
a4 Southern Derbyshire Health Authority, Derment Court, Stuart St, Derby DE1 2FZ

Article author query
marks p   [PubMed][Google Scholar] 
vipond i   [PubMed][Google Scholar] 
regan f   [PubMed][Google Scholar] 
wedgwood k   [PubMed][Google Scholar] 
fey r   [PubMed][Google Scholar] 
caul e   [PubMed][Google Scholar] 


An outbreak of gastroenteritis affected a school attended by children aged 4–11 years. Epidemiological features suggested this was due to Norwalk-like virus (NLV) and this was confirmed by polymerase chain reaction (PCR). Nucleotide sequence analysis of the PCR amplicons revealed identical strains in all five positive stool samples. Pupils were significantly more likely to become ill following an episode of vomiting within their classroom (adjusted odds ratio 4·1, 95% CI 1·8–9·3). The times from exposure to illness were consistent with direct infection from aerosolized viral particles where exposure to vomiting was high.

Cleaning with quaternary ammonium preparations made no impact on the course of the outbreak. However, the outbreak stopped after the school closed for 4 days and was cleaned using chlorine-based agents. This study confirms the importance of vomiting in the transmission of NLV and provides evidence that direct infection with aerosolized viral particles occurs.

(Accepted March 20 2003)

c1 Division of Epidemiology and Public Health, D Floor, Medical School, Queens Medical Centre, Nottingham NG7 2UH, UK.