First report of the protozoan parasite Perkinsus marinus in South America, infecting mangrove oysters Crassostrea rhizophorae from the Paraíba River (NE, Brazil).

Abstract The present work aimed to study the infection by Perkinsus sp. in the mangrove oysters Crassostrea rhizophorae from the estuary of the Paraiba River (Paraiba State, Brazil). Perkinsosis was detected by incubation of oyster gill pieces in Ray’s fluid thioglycollate medium. The monthly prevalence values were all above 70%, thus infection was not likely to be a transient event. Perkinsus sp. parasites isolated from eight oysters were propagated in vitro . PCR–RFLP analysis of in vitro cultured cells as well as the sequences of the rDNA ITS region allowed the identification of the in vitro propagated parasites as Perkinsus marinus . Phylogenetic analyses using rDNA ITS region sequences strongly supported the Perkinsus sp. from Paraiba in a monophyletic group with P. marinus . Thus, the results confirmed the species affiliation of Paraiba Perkinsus sp. as P. marinus . This is the first report of P. marinus in Brazil and South America and the first report of P. marinus naturally infecting C. rhizophorae .