A dot immunobinding assay in comparison with the gel diffusion test for the detection of equine herpesvirus-1 antigen from field samples.

The research article reports the development and comparison of a more efficient method (dot immunobinding assay or DIA) for detecting the equine herpesvirus-1 antigen, particularly in samples collected from horse abortion, stillbirth, newborn foal death and paralysis cases. This method outperforms the conventional agar gel immunodiffusion (AGID) in speed, sensitivity, specificity and affordability.

Dot ImmunoBinding Assay (DIA) for Equine Herpesvirus-1 Detection

• The authors focused on establishing an efficient method for detecting equine herpesvirus-1, which usually affects horses, causing abortion, stillbirth, newborn foal death, and paralysis.
• They devised a dot immunobinding assay (DIA) based on the principles of the enzyme-linked immunosorbent assay (ELISA). The DIA involves the absorption of an antigen (pathogenic substance) onto a nitrocellulose membrane to form a dot. The presence of the antigen is then confirmed via a colored dot after adding a specific enzyme that reacts with it.

Comparison of DIA and AGID

• Around 61 samples collected from field cases were tested by both DIA and the traditional agar gel immunodiffusion (AGID) to compare their effectiveness in detecting the equine herpesvirus-1 antigen.
• Results from DIA showed that 44 of the 61 samples (72%) were positive for the virus antigen, while the AGID test only identified 22 of the 61 samples (36%) as positive.

Advantages of DIA

• DIA not only demonstrated greater sensitivity (ability to correctly identify those with the disease) and specificity (ability to correctly identify those without the disease) but was also quicker compared to the traditional AGID test.
• Moreover, it proved to be reagent-conservative, meaning it uses fewer reagents, thus reducing costs. It was also noted to be simpler to perform, making it favorable for routine field use.