First report of Perkinsus sp. infection in the bivalve Magallana bilineata (Roding, 1798) from Pulicat Lake, Tamil Nadu, south-east coast region of India

Abstract

Perkinsus sp., an important protozoan parasite of mollusca is reported in the bivalve Magallana bilineata (Roding, 1798) for
the first time from Pulicat Lake, Thiruvallur District, Tamil Nadu, south-east coast of India. Molluscs collected from Pulicat
Lake were screened for Perkinsus sp. as part of a state-wide aquatic animal disease surveillance programme. Perkinsus sp.
infection was diagnosed based on culture in Ray’s Fluid Thioglycolate Medium (RFTM), histology as well as by molecular
analyses. Microscopic analysis of the RFTM supernatant revealed enlarged blue-black hypnospores characteristic of
Perkinsus sp. like organisms and typical ‘signet ring’ stages of trophozoites. Histological preparation of the molluscan gills
also revealed trophozoites. PCR amplification of genomic DNA isolated from infected specimens using specific internal
transcribed spacer (ITS) 85 and ITS 750 primers resulted in 703 bp DNA fragments specific for Perkinsus sp. BLAST
analysis of the sequence revealed 97% homology with Perkinus marinus.
Keywords: Dermocystidium, OIE, Perkinsus marinus, Protozoan parasite