First record of Perkinsus chesapeaki infecting Crassostrea rhizophoraein South America

Abstract

This study investigatedPerkinsusspp. infectingCrassostrea rhizophoraefrom the Jaguaribe River estuary,Ceará, Brazil. Fragments of gills and rectum of the oysters (n = 150) were incubated in Ray’s fluid thiogly-collate medium (RFTM). GenusPerkinsus-specific PerkITS85/750 PCR assays were performed and theiramplicons were sequenced by the Sanger method. The RFTM assays confirmedPerkinsusspp. Thesequencing of the amplified fragments from the rDNA internal transcribed spacers (ITS) ofPerkinsusspp. confirmedPerkinsus chesapeaki. Neighbor-Joining analyzes placeP. chesapeakiidentified in this studyin a well-supported clade with other isolates of the same species. This is the first record ofP. chesapeakiinfectingC. rhizophoraein South America.Ó2016 Elsevier Inc. All rights reserved.1. IntroductionThe estuary of the Jaguaribe River (Ceará State, Northeast Brazil)has great importance both from an ecological point of view, as wellas for supporting fisherman communities, as a mollusk collectingsite for consumption and marketing. Mollusks from natural envi-ronments and also from cultivation can be affected by differentgroups of pathogens, including protozoa belonging to the genusPerkinsus. This genus currently has seven accepted species. Amongthem,P. marinusandP. olsenirequire mandatory reporting to theWorld Organization for Animal Health, due to the risk that theyrepresent for mollusk populations (Villalba et al., 2004; Choi andPark, 2010). In Brazil, studies on perkinsosis have attracted atten-tion since the first record ofPerkinsussp. was made inCrassostrearhizophoraefrom the Pacoti River estuary, Ceará (Sabry et al.,2009).Sabry et al. (2013)confirmed that the species ofPerkinsusaffecting oysters in that estuary wasP. beihaiensis. In this sameyear, the first South American records were published ofP. marinusinfectingC. rhizophoraefrom the estuary of Paraíba River (da Silvaet al., 2013) andPerkinsussp. infecting the same species of oysterfrom the coast of Bahia State (Brandão et al., 2013). Recently,Perkinsussp. andP. marinuswere reported infectingCrassostreagasarfrom Paraíba State (Queiroga et al., 2013, 2015.),P. marinusandP. olseniwere identified inC. gasarfrom the estuary of theSão Francisco River, Sergipe State (da Silva et al., 2014) andP. beihaiensiswas recorded inAnomalocardia brasilianafrom theTimonha River estuary, Ceará State (Ferreira et al., 2015). Thisstudy investigated the presence and prevalence ofPerkinsusspp.inC. rhizophoraefrom the estuary of the Jaguaribe River, Ceará,Brazil.2. Materials and methodsThe oysters were manually collected from the roots ofRhizophorae mangleat low tide in the estuary of the Jaguaribe River(04°27039,2100S, 37°47031,6800W), on the east coast of Ceará State.Collections were made in March 2012 (N = 150) during the rainyseason (January-April) and October (N = 150) of the same year dur-ing the dry season (May-December). The temperature and salinitydata were measured during the sampling. The oysters were trans-ported to the laboratory alive in isothermal boxes. Prior to process-ing, the animals were measured for shell height, according toGaltsoff (1964). Two gill lamellae and the rectum of each oysterwere incubated in Ray’s fluid thioglycollate medium in thepresence of antibiotics and antifungals (penicillin/streptomycinand nystatin) for 7 days in the dark at room temperature.