The development of an accelerated reverse-transcription loop mediated isothermal amplification for the serotype specific detection of bluetongue virus 8 in clinical samples

In 2006 bluetongue virus serotype 8 (BTV 8) was identified for the first time in the Netherlands causing a major epidemic in sheep and cattle that quickly spread to neighbouring Belgium, Germany and beyond to France and the UK. This resulted in severe animal health and welfare problems as well as substantial economic losses to the agrifood industries of these countries. Given that the early diagnosis of BTV infection 'in-the-field' is extremely useful to its subsequent management and control, this study was established to design a novel, sensitive and rapid nucleic acid diagnostic test for the serotype-specific detection of BTV 8, which could be used without the use of advanced laboratory support and equipment. Primers for the detection of BTV 8 were based on genome segment 2 of the virus, the VP2 gene. The assay was assessed using a full panel of BTV reference strains and clinical samples. Positive amplification was observed using a fluorescent detection reagent. The sensitivity of the RT-LAMP assay was 102 copies of RNA. The assay did not amplify the closely related orbivirus EHDV. This novel RT-LAMP offers a sensitive, specific and rapid method of detecting BTV 8. The approach is inexpensive and easy to use and could potentially be used in a 'pen-side' setting 'in the field' or by smaller less well-equipped laboratories in developing countries.