Perkinsus sp. infecting three important mollusks from Jaguaribe River estuary, Ceará, Brazil / Perkinsus sp. infectando três importantes moluscos do estuário do Rio Jaguaribe, Ceará, Brasil

This work investigated the occurrence of Perkinsus sp. in clam Anomalocardia brasiliana, oyster Crassostrea sp. and mussel Mytella falcata from the Jaguaribe River estuary, northeastern Brazil. The collection of clam (N = 300), oysters (N = 300) and mussels (N = 300) were carried out in the estuary of the Jaguaribe River, Ceará, in March and April (rainy season) and October (dry season) in 2017. The mollusks were measured in their major axis, open, and had their tissues submitted to tissue incubation techniques in Ray's fluid thioglycollate medium (RFTM), histology, real-time polymerase chain reaction (qPCR), PCR and sequencing. The RFTM assays showed Perkinsus sp. infecting the three mollusks investigated. The prevalence of infected clams was 1.33% in both sampling periods, oysters ranged from 2.66 (rainy season) to 8% (dry period), and mussels from 0% (dry period) to 51.33% (rainy season). The intensity of infection was very light to light in clams, very soft to severe in oysters and very soft to moderate in mussels. Histological analyses showed cells of Perkinsus sp. infecting the gills and connective tissue around the digestive gland of some individuals. The qPCR generated amplicons in all positive samples in RFTM, confirming the presence of Perkinsus sp., while the sequencing evidenced high similarity (99%) with the species P. beihaiensis. In conclusion, the results obtained contribute to increasing knowledge about the occurrence of Perkinsus sp. in bivalve mollusks from northeastern Brazil.(AU)

Foi investigada a ocorrência da infecção pelo protozoário Perkinsus sp. em berbigões Anomalocardia brasiliana, ostras Crassostrea sp. e mexilhões Mytella falcata do estuário do Rio Jaguaribe, Nordeste do Brasil. As colheitas dos berbigões (N = 300), ostras (N = 300) e mexilhões (N = 300) foram realizadas no estuário do Rio Jaguaribe, Ceará, nos meses de março e abril (período chuvoso) e outubro (período seco) de 2017. Os moluscos foram medidos em seu maior eixo, abertos e os seus tecidos foram submetidos às técnicas de incubação de tecidos em meio fluido de tioglicolato de Ray (RFTM), histologia, reação em cadeia da polimerase em tempo real (qPCR), PCR e sequenciamento. Os ensaios de RFTM evidenciaram Perkinsus sp. infectando os três moluscos investigados. A prevalência de berbigões infectados foi de 1,33% em ambos os períodos de amostragem, a de ostras variou de 2,66 (período chuvoso) a 8% (período seco) e a de mexilhões de 0% (período seco) a 51,33% (período chuvoso). A intensidade de infecção apresentou-se muito leve a leve em berbigões, muito leve à severa nas ostras e muito leve à moderada nos mexilhões. As análises histológicas mostraram células de Perkinsus sp. infectando as brânquias e tecido conjuntivo em torno da glândula digestiva de alguns indivíduos. A qPCR gerou amplicons em todas as amostras positivas em RFTM, confirmando a presença de Perkinsus sp., enquanto o sequenciamento mostrou alta similaridade (99%) com a espécie P. beihaiensis. Em conclusão, os resultados do presente estudo contribuem para ampliar o conhecimento sobre a ocorrência de Perkinsus sp. em moluscos bivalves do Nordeste do Brasil.(AU)

First record of Perkinsus chesapeaki infecting Crassostrea rhizophorae in South America.

This study investigated Perkinsus spp. infecting Crassostrea rhizophorae from the Jaguaribe River estuary, Ceará, Brazil. Fragments of gills and rectum of the oysters (n=150) were incubated in Ray's fluid thioglycollate medium (RFTM). Genus Perkinsus-specific PerkITS85/750 PCR assays were performed and their amplicons were sequenced by the Sanger method. The RFTM assays confirmed Perkinsus spp. The sequencing of the amplified fragments from the rDNA internal transcribed spacers (ITS) of Perkinsus spp. confirmed Perkinsus chesapeaki. Neighbor-Joining analyzes place P. chesapeaki identified in this study in a well-supported clade with other isolates of the same species. This is the first record of P. chesapeaki infecting C. rhizophorae in South America.