Development and application of an immunoassay diagnostic technique for studying Hematodinium infections in Nephrops norvegicus populations

Patent Hematodinium infections of the Norway lobster Nephrops norvegicus ca n be detected with a morphological method (pleopod diagnosis), but this fai ls to identify low-level haemolymph (sub-patent) and any tissue-based (late nt) infections. The current study describes the development and application of an immunoassay for the detection of antigens of the parasite Hematodini um in the Norway lobster N. norvegicus. Infected tissue and haemolymph samp les were detected as multiple-band reactions to a polyclonal antibody (anti -Hematodinium), The sensitivity limit of the method was 204 parasites mm(-3 ), approximately 10 times more sensitive than the pleopod diagnosis method. Use of the immunoassay on tissue samples taken from catches in the Clyde S ea area, Scotland, UK, showed that the pleopod method considerably under-di agnosed infection prevalence in the early part of the season, though this u nder-diagnosis decreased as infected lobsters in the field progressed from latent and sub-patent to patent infections. However, the immunoassay failed to detect any infected lobsters during the summer months, suggesting that infection may not be carried over from one season to the next. The data pre sented suggest that this immunoassay allows for the accurate estimation of Hematodinium infection prevalence in the field and should be employed, wher e possible, for the routine monitoring of infection prevalence in N. norveg icus.