Author's personal copy Two Perkinsus spp. infect Crassostrea gasar oysters from cultured and wild populations of the Rio São Francisco estuary, Sergipe, northeastern Brazil Patricia Mirella da Silva a,c,⇑ , Marcos Paiva Scardua b,1 , Rogério Tubino Vianna a,2 , Raoani Cruz Mendonça a , Cairé Barreto Vieira c , Christopher F. Dungan d , Gail P. Scott e , Kimberly S. Reece e a Núcleo de Engenharia de Pesca, Universidade Federal de Sergipe, CEP 49100-000 Aracajú, SE, Brazil b Embrapa Tabuleiros Costeiros, Bairro Jardins, Caixa Postal 44, CEP 49025-040 Aracajú, SE, Brazil c Departamento de Biologia Molecular, Universidade Federal da Paraíba, CEP 58051-900 João Pessoa, PB, Brazil d Maryland Department of Natural Resources, Cooperative Oxford Laboratory, 904 S. Morris Street, Oxford, MD 21654, USA e Virginia Institute of Marine Science, College of William & Mary, P.O. Box 1346, Gloucester Point, VA 23062, USA article info Article history: Received 20 December 2013 Accepted 17 April 2014 Available online 26 April 2014 Keywords: Perkinsus olseni Perkinsus marinus Oysters Crassostrea gasar Histopathology rDNA abstract Brazilian production of bivalve molluscs is small but expanding, especially in the northeastern region where the native oysters Crassostrea rhizophorae and C. gasar are abundant, and tropical weather pro- motes their rapid growth. Studies on bivalve pathology are scarce in Brazil, with only a few employing techniques for detecting protozoan pathogens listed by the World Organisation for Animal Health (OIE). In 2008, a Perkinsus sp. was reported for the first time in Brazil, infecting C. rhizophorae oysters from a wild population in Ceará state, NE Brazil. Recently P. marinus was detected in the same oyster species in nearby Paraíba state. These findings highlighted the need to expand knowledge on the presence and impacts of Perkinsus spp. on Brazilian oyster populations. The current investigation evaluated Perkinsus sp. infections among wild and cultured C. gasar mangrove oysters from the estuary of the Rio São Fran- cisco, Sergipe state, NE Brazil. Our results show that Perkinsus sp. infections occurred commonly in oys- ters of both groups, at prevalences that were frequently higher among cultured oysters. Prevalences varied seasonally, with maximum values during summer (January) of 57% and 80% for wild and cultured oysters respectively, and minimum values during winter (July). Results of DNA sequencing, in situ hybrid- ization assays, and phylogenetic analyses showed dual- and single-pathogen infections by P. marinus and/ or P. olseni in the tested oysters. Ó 2014 Elsevier Inc. All rights reserved. 1. Introduction The native oysters Crassostrea rhizophorae and C. gasar were the first bivalve molluscs to be experimentally cultured in Brazil dur- ing the 1970s. During the same decade, Pacific oysters C. gigas were introduced for commercial culture along the coasts of Rio de Janeiro, São Paulo, and Santa Catarina states of southern Brazil, where moderate seasonal water temperatures of 16–30 °C occur, but rarely surpass 26 °C(Ferreira et al., 2004). Culture of C. gigas in northeastern Brazil was not attempted, due to incompatible tropical seawater temperatures (25–30 °C). However, the northeast region of Brazil has approximately 3000 km of coastline with calm waters and deep estuarine extensions that are suitable for produc- tion of native oysters. Despite their wide distributions along the Brazilian coast (Rios, 2009), however, commercial production of the common native oysters C. rhizophorae and C. gasar has lagged behind production of Pacific oysters in Brazil, which reached 15,636 t in 2010 (EPAGRI, 2012; http://cedap.epagri.sc.gov.br/). In the northeastern state of Sergipe, fish and shrimp culture are dominant, with oyster aquaculture increasing under encourage- ment from local and national governments. The fishery production of bivalve molluscs in Sergipe during 2007 was 3.8 t of Crassostrea spp. oysters and 638.9 t of Mytella spp. mussels (IBAMA, 2007). A http://dx.doi.org/10.1016/j.jip.2014.04.005 0022-2011/Ó 2014 Elsevier Inc. All rights reserved. ⇑ Corresponding author at: Departamento de Biologia Molecular, Universidade Federal da Paraíba, Centro de Ciências Exatas e da Natureza, Jardim Universitário s/n, Bairro Castelo Branco, CEP 58051-900 João Pessoa, PB, Brazil. Fax: +55 83 32167643. E-mail addresses: mirella_dasilva@hotmail.com (P.M. da Silva), mscardua@hot- mail.com (M.P. Scardua), rtvianna@gmail.com (R.T. Vianna), raoani@hotmail.com (R.C. Mendonça), cairebarreto@gmail.com (C.B. Vieira), cdungan@dnr.state.md.us (C.F. Dungan), gpscott@vims.edu (G.P. Scott), kreece@vims.edu (K.S. Reece). 1 Instituto Federal de Educação Ciência e Tecnologia do Ceará, CEP 62800-000 Aracati, CE, Brazil. 2 Universidade Federal do Rio Grande, CEP 96203-900 Rio Grande, RS, Brazil. Journal of Invertebrate Pathology 119 (2014) 62–71 Contents lists available at ScienceDirect Journal of Invertebrate Pathology journal homepage: www.elsevier.com/locate/jip