Brote de gastroenteritis por norovirus GII.17 en una residencia de mayores

Introduction

Gastrointestinal norovirus infections are highly prevalent, causing outbreaks especially in institutions such as nursing homes. We describe an outbreak caused by an emerging norovirus genotype.

Material and methods

We defined a case as a resident or worker of the centre with clinical signs and symptoms of AGE from 14 to 29 May 2022, with no underlying pathology to justify it. A clinical-epidemiological survey was carried out and stool samples were collected from patients with diarrhoea at the time of the study. Virological analysis was performed at the Microbiology Department of our hospital by antigenic detection (Certest®, Biotec SL) and/or multiplex PCR (AllplexTM GI-Virus Assay, Seegene®). Viral genotyping by sequencing was performed by the Centro Nacional de Microbiología (CNM).

Results

The outbreak totaled 114 cases (99 residents, 15 workers), extending over 16 days. The most frequent symptoms were vomiting and diarrhoea. The overall attack rate was 30.8% (in workers 12.7%). Cases increased rapidly in the first 48 hours, falling progressively over successive days. Food contamination was ruled out, with person-to-person transmission being the most likely. Those affected improved clinically in less than 72 hours, with no deaths. We tested 14 samples from residents, which were positive for norovirus GII. The CNM received 8 samples, detecting norovirus genogroup GII, genotype 17 [P17] in 6.

Conclusions

Outbreaks of norovirus GEA in nursing homes can affect numerous users. In our case, norovirus genotype GII.17 was the aetiological agent, confirming its widespread dissemination in the last decade worldwide.