Development of an avidin-biotin dot enzyme-linked immunosorbent assay and its comparison with other serological tests for diagnosis of glanders in equines.

This research investigated the development of a new test called the dot enzyme-linked immunosorbent assay (dot ELISA) for diagnosing glanders in equines (horses), and compared its efficacy with existing tests. The dot ELISA test proved superior in terms of sensitivity, speed, ease of use, interpretability of results, and early detection capability.

Development of Dot ELISA Test

• The researchers designed a dot enzyme-linked immunosorbent assay (dot ELISA) meant for diagnosing glanders in horses. Glanders is a highly infectious disease caused by the bacterium Pseudomonas mallei.
• The technique was based on detecting IgG antibodies – the chief type of antibody the body produces when fighting off infections, more specifically to the antigens of Pseudomonas mallei.
• The antigens were attached to a nitrocellulose coated plastic strip or dipstick. The reaction between the IgG antibodies and antigens was enhanced using a system composed of avidin and biotin, along with biotinylated anti-horse IgG and horseradish peroxidase-avidin D.

Test Analysis and Comparison

• The newly developed dot ELISA was used on samples from 810 normal horses, six naturally infected ones, and 48 sensitized horses.
• The results from the dot ELISA were compared to results from other established tests such as the complement fixation test, the indirect haemagglutination test, and the counter-immunoelectrophoresis test.
• Through this comparison, it was found that the dot ELISA had the highest sensitivity – indicating its superior ability to correctly identify true positive cases of glanders.

Advantages of Dot ELISA

• Aside from its high sensitivity, the dot ELISA test proved to have several advantages over the other tests. It was rapid and easy to perform, which makes it a practical option for widespread use.
• The results from the dot ELISA were also easy to interpret, reducing the risk of errors during diagnosis.
• Unlike some other tests, the dot ELISA test was not affected by anti-complement activity. Anti-complement antibodies can interfere with certain tests and make them less reliable.
• Finally, the dot ELISA had the ability to detect antibodies at an early stage, making it a potentially valuable tool for early treatment implementation, outbreak control, and subsequent reduction in disease spread.

Epidemiological Screening

• Based on the results of the research, it’s recommended to use the serum at 1:200 dilution for large-scale disease surveillance or epidemiological screening. This means that the test can be used to assess the prevalence and distribution of glanders in horse populations, an important aspect of controlling and preventing outbreaks.