[Molecular epidemiology study on an acute gastroenteritis outbreak caused by a new GII. 4 norovirus recombinant strain].

OBJECTIVE

To analyze the epidemiological characteristics of an acute gastroenteritis outbreak in a nursing home caused by norovirus (NoV) and the genotype of the pathogen.

METHODS

On January 29th 2013, a total of 26 acute gastroenteritis patients infected by norovirus were reported in the nursing home of Jinshan, Shanghai. A questionnaire was used to acquire information of patients involved in the outbreak, 9 stool or anal swab samples were collected from 9 patients without treatment by simple random sampling method, and 4 environmental samples from the surface of doorknobs or toilets were collected. The samples were detected by Real-time PCR for NoV, and positive samples were then amplified by routine RT-PCR. The PCR products were purified, sequenced, and aligned by comparing sequences in GenBank. Phylogenetic trees were constructed by using Clustal X, employing MEGA 5.1 program package.

RESULTS

For the 26 patients, 7 were men and 19 were women.8 samples were found NoV positive among the 13 samples when detected by real-time PCR. The sequence alignment showed that the nucleotide sequence homology between Jinshan08 and Jinshan12 strain which obtained sequencing signal was 100%. The phylogenetic analysis revealed that Jinshan08, Jinshan12 and GII.e/NV2634/BCN/Spain/2008 strains in the RdRp region were on the the same branch of evolutionary tree, the confidence level was 99%, and in the N/S region of the Capsid, 2 other strains and Lordsdal strain were in the same branch, the confidence level was 97%.

CONCLUSION

It was confirmed that the acute gastroenteritis outbreak was caused by the new GII.4 NoV recombinant.