First report of an astrovirus type 5 gastroenteritis outbreak in a residential elderly care home identified by sequencing

BACKGROUND: This is the report of an outbreak of human astrovirus type 5 gastroenteritis that occurred in a residential care home for older people in June 2013 in Tayside, Scotland, and which involved seven staff members and thirteen residents. This type of astrovirus has not been found in Scotland before and is rarely described in the literature.OBJECTIVES: Using molecular methods such as PCR and sequencing to detect the cause of this gastroenteritis outbreak and to contain the outbreak using Public Health measures.STUDY DESIGN: Following an epidemiological investigation, stool samples were sent for routine virology and microbiology testing at the local microbiology and virology laboratory and were found to be negative. Further testing with real-time PCR and gene sequencing at the West of Scotland Specialist Virology Centre was performed. Data on the epidemiology and the response to the outbreak was collected.RESULTS: All samples had a 99% match to human astrovirus type 5. The use of standard infection control precautions with the addition of transmission-based precautions most likely contained the spread of the virus in this situation.CONCLUSIONS: This report illustrates the importance of using PCR and sequencing to identify pathogens such as astrovirus in outbreaks of vomiting and diarrhoea in older people particularly if routine virology and microbiology tests are negative.