Sparicotyle chrysophrii and gilthead sea bream - potential experimental infection model

An infection model of gilthead sea bream challenged with the monogenean Sparicotyle chrysophrii is described herein. Its design aimed to simulate the pathogenesis in situ. One thousand farmed fish (16 g) in a cement tank were heavily infected by adult parasites two weeks following the transfer of the 250 donor fish (50 g). Anorexia, lethargy and anaemia along with 15 % cumulatively mortalities were observed. A parasitological analysis carried out at end of the experiment (12 weeks) revealed that 7 % of the examined population was pathogen free and the mean intensity was 6.4 parasites/fish. Surprisingly, growth reduction of infected fish was not correlated with the parasitic load, perhaps due to the unfavourable feeding ground for the parasite in anaemic small fish. Overall, the described infection pattern resembles the characteristics of the disease seen in the field and could be ideally adopted in controlled environments.