WOS: 000305319800004The efficacy of oral administration of trichlorfon on cultured sea bass (Dicentarchus labrax) naturally infected with Diplectanum aequans has been investigated. Sea bass (weighing 80-100 g, mean weight 92 +/- 1 g SD) received a daily dosage of 50 mg kg(-1) trichlorfon in feed to for 7 days. On day 0, 7, 14 and 21 of the experiment, fish were randomly sampled and then parasites on the gills were counted. Comparisons were made to untreated control fish. At the beginning of the experiment all examined fish were infected with D. aequans. There were no statistical differences (P>0.05) in terms of mean number of D. aequans within each group, including the control. During the treatment period, the prevalence decreased in the medicated group by 5 %, 52 %, and 35 % on day 7, 14 and 21, respectively when compared to that of the control group. No mortality was found and adverse drug reactions or palatability problems were not associated with the treatments during the study. The drug may be used during acute outbreaks but due to the risk of anthelmintic resistance this treatment regime cannot be recommended for regular use
