Seasonal screening for viral gastroenteritis in young children and elderly hospitalized patients: is it worthwhile?

BACKGROUND

Viral gastroenteritis is common, especially in young children. In adults, particularly amongst the elderly, it can lead to outbreaks at a time when demands on clinical services are at their peak.

AIM

To evaluate seasonal screening of young children and elderly patients with suspected viral gastroenteritis using multiplex polymerase chain reaction (PCR) for enteric viruses within a general hospital setting.

METHODS

Stool samples from 200 children aged five years and under were screened for rotavirus, adenovirus, astrovirus, sapovirus and norovirus using multiplex PCR and a combined rotavirus/adenovirus immunochromatographic test (ICT) during the winter of 2012. Diarrhoeal samples submitted to the laboratory from 195 adults aged 65 years and over attending as inpatients were also evaluated by multiplex PCR.

FINDINGS

One or more enteric viruses were detected by PCR in 56% of children. Rotavirus was the most prevalent virus, found in 19% of samples. Enteric (diarrhoea-associated) adenovirus was detected in 5% of samples and non-enteric adenovirus was detected in 14% of samples. Astrovirus, norovirus and sapovirus were detected in 18%, 12% and 10% of samples, respectively. The ICT yielded a slightly lower rate for rotavirus and enteric adenovirus, but gave more rapid results. Norovirus, rotavirus and adenovirus were detected in 15%, 2.5% and 1% of elderly adults attending hospital as inpatients, respectively.

CONCLUSIONS

Rapid screening of young children (for rotavirus, adenovirus and norovirus) and symptomatic, elderly adults (for norovirus) during winter months may help to limit nosocomial spread.

Emergence of the GII-4 Norovirus Sydney2012 strain in England, winter 2012-2013

Norovirus is the commonest cause of acute gastrointestinal disease and is the main aetiological agent of outbreaks of gastroenteritis, particularly in semi-closed environments. Norovirus infections in England typically peak between December and March each year. The most commonly detected norovirus strains belong to the genetically diverse genogroup-II genotype-4 (GII-4) genocluster and in the previous two norovirus winter seasons the majority of GII-4 strains in circulation worldwide have been genetically similar to the GII-4 strain New Orleans 1805/2009/USA. At the beginning of the 2012/13 season a genetically distinct GII-4 strain (Sydney 2012/NSW0514/2012/AU) was described which emerged worldwide during the winter of 2012/13. Here we describe the emergence of norovirus strains genetically related to Sydney2012 in England during the 2012/13 season to replace NewOrleans2009 strains as the most commonly detected variant of GII-4 norovirus in England. Furthermore, we demonstrate that whilst the emergence of Sydney2012 coincided with an early peak in the number of norovirus outbreaks, there was not an overall increase in norovirus activity compared to the previous season. Finally, we show that the Sydney2012 strain is associated with distinct genetic changes compared to the NewOrleans2009 strain, and these changes may have contributed to the emergence of the Sydney2012 strain.