Diagnosing bluetongue virus in domestic ruminants: current perspectives

Figures & data

Table 1 Virus detection techniques

Test	Status	Advantage	Usage
Virus detection techniques
Immunofluorescence	In use	Complement the full pathogen characterization	Used mainly in experimental pathogenesis
Competitive ELISA (c-ELISA)	Used routinely in many laboratories	Highly sensitive technique	Detection of the presence of BTV antigens
Dot immunoblotting	Not widely used	Sensitive for serotypes 1–18 and 20	Detection of virus
Electron microscopy	Not widely used for diagnosis	Identification of virus as well as cellular pathology caused by the virus	Diagnosis of unknown etiology virus
Standard RT-PCR	In use but replaced by real time RT-PCR	Sensitivity	Detection of BTV RNA
Real-time RT-PCR	In use	Analytically sensitive and reduced contamination	Detection of BTV RNA
Multiplex PCR	In use	Identified multiple serotypes simultaneously	Detection of BTV RNA
Sequencing	In use	Classification into serogroup, serotype, and topotype	Obtain full genomic sequence of BTV
Antibody detection techniques
Agar gel immunodiffusion	Into abeyance	Easy and quick to perform	Detection of BTV antigens
i-ELISA and c-ELISA	Most commonly used	Reliable and robust, commercially available	Detection of BTV antigens
VNT	Diminished use due to cost and labor	Very useful in epidemiology studies	Detection of serotype-specific antibodies
IgM-capture ELISA	Complementary to current tests	New technologies	Detection of BTV antibodies in recent infected cattle
Immunochromatographic strips	Not widely used	Rapid and high specificity	Detection of antibodies to VP7
Protein chips	Not widely used	New technique under development	Detection of antibodies to VP7
Latex agglutination test	Not widely used	New technique under development. Good for large number of samples	Detection of antibodies to VP7
Double-antigen MIA	Not widely used	High specificity and efficiency compared with c-ELISA, while VP2-MIA was as specific as a VNT	Detection of antibodies to VP2 and VP7 simultaneously

Abbreviations: BTV, bluetongue virus; i-ELISA, indirect ELISA; MIA, microsphere immunoassay; RT-PCR, reverse-transcription polymerase chain reaction; VNT, virus neutralization assay.