BT Serotype diagnosis: Second step
Genome segment 2 (Seg-2) encodes outer-capsid protein VP2, the most variable BTV protein and the primary target for neutralising antibodies. Consequently VP2 (and Seg-2) determine the identity of the twenty-four notifiable serotypes and additional atypical BTV serotypes that have been recognised so far.
Virus neutralisation tests (VNT) and seroneutralisation tests (SNT) are the “gold standard” method for BTV serotyping. However, serological procedures are expensive and time-consuming and are often associated with poor sensitivity.
Highly sensitive and specific molecular ‘typing’ assays, targeting Seg-2 (including conventional, RT-PCR, sequencing and probe-hybridization methods) have previously been reported for identification of BTV serotypes in response to specific epidemiological situations.
However primers and probes to detect 26 BTV serotypes described by Maan et al. 2016 is the most extensive work, validated using more than 1000 strains, including two novel serotypes and further introductions at date of exotic serotypes and topotypes into new geo-graphic areas.
| Serotype identification methods |
|---|
| BLUETONGUE |
| Detection of ab against Orbivirus by SNT |
| rRT-PCR for BTV typing (Maan 2016) |