3.4.1. Enzyme-linked Immunosorbent Assay (ELISA).
Ragsdale and Furgala (1987) developed antiserum against A. woodi where infested tracheae were detected using a direct enzyme-linked immunosorbent assay (ELISA); this method was further modified by Ragsdale and Kjer (1989). This assay was sensitive enough to detect a very low level of tracheal mite infestation but was found to cross-react with other proteins present in the haemolymph and thoracic muscles. The lack of specificity limits the application of this test to tracheal preparations. A practical ELISA test was developed by Grant et al. (1993) where whole bee samples could be analysed for HBTM detection, but the sensitivity of the test was reduced when mite prevalence fell below 5%.