Authors

Discussion

Amoebic gill disease (AGD) is a devastating disease that causes multi-million-dollar losses annually in salmonid fish farming. The causative agent of AGD in Atlantic Salmon is Neoparamoeba perurans which belongs to the Paramoebidae family. An interesting feature of most of the Paramoebidae is the endosymbiotic relationship they have with the Perkinsela-like organism (PLO). The PLO is a kinetoplastid, distantly related to the Tritryps parasites. As there appears to be a high level of metabolic interdependence between host and symbiont, eliminating the PLO, which resides adjacent to the nucleus of its symbiotic host, will hypothetically eliminate N. perurans. To this end, we have chosen to co-opt frontline and experimental trypanocidal drugs to target the PLO.

N. perurans cannot be grown axenically, so traditional drug screening methods are impeded by bacterial activity within the amoebic culture. To assay in vitro efficacy, holographic microscopy was used to assay cell motility and viability under drug pressure. Drugs which showed good in vitro efficacy were then deployed during two rounds of in vivo trials on the West Coast of Ireland, with promising signs of efficacy. We hope that providing a market for trypanocidal drugs in aquaculture may not only improve fish welfare but also lower their cost of production for deployment in a medical context in the tropics.

Keywords: endosymbiosis, kinetoplastid, amoeba, amoebic gill disease, anti-leishmanial, anti-trypanosomal, holographic microscopy, drug screening method