What to know
- Below are confirmed norovirus outbreaks submitted to CaliciNet and updated monthly.
- Participating public health laboratories electronically submit genotype information for norovirus and basic epidemiology data from norovirus outbreaks to the CaliciNet database.
- The data on norovirus strains are compared with existing norovirus sequences in the CaliciNet database.
Genotype distribution of norovirus outbreaks
September 1, 2023 – October 31, 2024 (n=320)
The Other Genotypes category includes genotypes from outbreaks that each make up less than 5% of the total number of outbreaks. These genotypes are: GI.1[P1], GI.2[P2], GI.3[P3], GI.3[P13], GI.6[P11], GI.7[P7, ]GII.1[P33], GII.3[P12], GII.3[P25], GII.4 San Francisco[P31], GII.4 Sydney[P4], GII.7[P7], GII.8[P8] GII.10[P16], GII.12[P16], GII.13[P16], GII.14[P7], GII.17[P untypeable].
Data Table: September 1, 2023 – October 31, 2024 (n=320)
| Genotype | Number of Outbreaks |
|---|---|
| GII.17[P17] | 116 |
| GII.4 Sydney[P16] | 84 |
| GII.6[P7] | 29 |
| GI.5[P5] | 27 |
| GII.2[P16] | 14 |
| Other Genotypes | 50 |
Data Table: September 1, 2022 – August 31, 2023 (n=368)
| Genotype | Number of Outbreaks |
|---|---|
| GII.4 Sydney[P16] | 167 |
| GII.6[P7] | 31 |
| GII.17[P17] | 27 |
| GI.3[P13] | 19 |
| GII.3[P12] | 18 |
| Other Genotype | 106 |
Dual typing for norovirus
Dual typing for norovirus is being implemented by laboratories participating in CaliciNet.
Dual typing is RT-PCR amplification of a partial region of both the polymerase gene and the capsid gene (region B-C) in a single reaction for genogroup I or genogroup II noroviruses.