Protocol of identification and quantification of bucephalosis (orange disease) in the mussel Perna perna

Abstract

This study proposes a protocol for the identification and quantification of bucephalosis in the mussel Perna perna by classical histology and stereological methods. Among fifty animals with length between 30 and 70 mm, proceeding from experimental mussel culture strings of Universidade Federal de Santa Catarina, at Sambaqui Beach - Florianópolis/SC, six animals infected with Bucephalus sp. were identified, corresponding to a prevalence of 12%. Inclined transverse sections of the mollusks were fixed in Davidson’s solution, processed through classical histology, cut (3 µm) and stained with HHE. The fractional volume of the parasite tissue (PT), host tissue (HT) and empty spaces (ES) were quantified by Weibel graticule attached to a microscope. The objective of 10x was more efficient than that of 40x, for the stereological analysis of the sections. Half of the infected animals presented a moderate rate of parasite infection (5 - 50% of the section with parasite tissue), while the other half presented greater rates (> 50%). Animals with light infection (< 5%) were not found.