Assessment of Oral Albendazole and Fumagillin in the Treatment of Pseudoloma neurophilia in Adult Zebrafish.

Pseudoloma neurophilia (Pn), the causative agent of the most commonly reported disease of zebrafish, is a microsporidianparasite that confounds research by inducing behavioral and physiologic changes in zebrafish. Although a treatmentfor P. neurophilia has not been documented in zebrafish, albendazole (ALB) and fumagillin (FUM) have been used to treatmicrosporidian infections of other fish species. To investigate the efficacy of oral ALB and FUM in the treatment of Pn, weperformed a pilot study that demonstrated the safety and palatability of novel gel-based diets containing FUM or ALB inadult AB zebrafish. In a subsequent study, approximately 250 adult AB zebrafish (previously infected with Pn) were treatedwith these medicated diets for 4 wk. At 4 different time points (weeks 0, 5, 10, and 16 of the study), fish were euthanized andwhole-body qPCR was performed to assess Pn prevalence across treatment and control groups. There was no statisticallysignificant association between treatment group and Pn prevalence at any time point, although potential biologically relevantreductions in Pn prevalence occurred in the combination therapy group at weeks 5 and 16 and in the ALB group at week 5.Based on high-performance liquid chromatography analyses, the medicated diets contained less ALB and more FUM thanexpected, highlighting the importance of validating medicated feed concentrations to ensure safety, efficacy, and consistency.While Pn remains challenging to eradicate and control, results of this study warrant further investigation into the utility ofALB and FUM as potential treatments for this pathogen.