Marteilia sp. and other parasites and pathological conditions in Solen marginatus populations along the Galician coast (NW Spain)

Abstract

This paper reports the results of the survey developed after the first detection of protozoan Marteilia sp. infection of the grooved razor shell Solen marginatus (Pulteney, 1799) from Galicia (NW Spain) in 2006. Furthermore, we analysed other parasites and pathological conditions found in grooved razor shell populations throughout this survey, such as metacercariae of trematodes, prokaryotic infections and disseminated neoplasms, some of which could cause moderate or severe damage to the host depending on the intensity of infection. A total of 17 natural beds distributed along the Galician coast were analysed, and Marteilia sp. was detected in 6 of them with low prevalence, moderate intensity and no negative effects over the populations.KEY WORDS: Grooved razor shell · Prokaryote · Protozoa · Metacercaria · Disseminated neoplasm · Histopathological survey Resale or republication not permitted without written consent of the publisherDis Aquat Org 112: [177][178][179][180][181][182][183][184] 2015 Villalba et al. 2014). In fact, infection by M. refringens is a notifiable disease listed by the World Organisation for Animal Health (2013) and under European legislation (Directive 2006/88). The aim of the present study was to survey for Marteilia sp. in S. marginatus and to characterize other parasites and pathological conditions affecting grooved razor shell along the Galician coast. MATERIALS AND METHODSSamples of 20 to 30 commercial grooved razor shells (> 80 mm length) were collected by hand using salt (spread in burrow entrances, causing the razor shells to leave the burrow) in 17 intertidal beds in northern and western rías along the Galician coast ( Fig. 1). Samplings were conducted seasonally, during the years 2008 to 2011 (previous data from the Redondela bed between the years 2006 and 2008 were also included), except in the Barraña and Mañóns beds, where samples were collected monthly and in the Cariño bed, where they were collected every 2 mo.In the laboratory, valves were separated, and gills, mantle and visceral mass were examined macroscopically for evidence of macroparasites, lesions, abnormal colouration and other malformations. A section including digestive gland, gonad, kidney, foot, mantle lobes, labial palps and gills was taken from every specimen, fixed in Davidson's solution (Shaw & Battle 1957) and embedded in paraffin. Paraffin blocks were sectioned at 5 µm with a rotary microtome. Tissue sections were deparaffinised, stained with Harris' haematoxylin and eosin and examined by light microscopy for symbionts and pathological conditions such as haemocyte infiltrations and neoplasms.To further characterize the prokaryotic colonies detected in histology sections stained with Harris' haematoxylin and eosin, additional staining techniques were used: Gram's Brown and Hopps method for Gram-positive and Gram-negative bacteria, the Pinkerton method for rickettsial organisms, the Ziehl-Neelsen method for acid-fast bacteria and the Feulgen method for DNA (Howard & Smith 1983).Some samples we...

Neoplastic diseases of marine bivalves

“…Prevalence ranged from 1% to 25% in affected populations of S. marginatus (Ruiz et al, 2015), while only one case (out of 311 analyzed clams; prevalence: 0.3%) was detected in E. siliqua (Ruiz et al, 2013a). Five populations of the stout razor clam Tagelus plebeius from Chesapeake Bay that were sampled during 2002, revealed DN in all samples, at prevalence ranging from 7-100% (mean 79%) (Dungan et al, 2005).…”

Parasites, pathological conditions and resistance to Marteilia cochillia in lagoon cockle Cerastoderma glaucum from Galicia (NW Spain)

“…Similar enveloped bacterial colonies have been observed in gills and mantle of common cockles C. edule, some of them with a high number of such colonies per section, which were associated with local lesions (Carballal et al 2001). Enveloped bacterial colonies have also been reported from other bivalve species (Joly 1982, Le Gall et al 1988, Goggin & Lester 1990, Villalba et al 1999, Costa et al 2012, Ruiz et al 2015.…”

Cosmopolitan Distribution of Endozoicomonas-Like Organisms and Other Intracellular Microcolonies of Bacteria Causing Infection in Marine Mollusks

“…Infections related to IMC in economically important marine molluskan species have been reported in Spain, infecting the common cockle Cerastoderma edulis (Carballal et al, 2001), the grooved razor shell Solen marginatus, the pod razor clam Ensis siliqua (Ruiz et al, 2013(Ruiz et al, , 2015 and the Mediterranean mussel Mytilus galloprovincialis (Villalba et al, 1997); in France, infecting the Mediterranean mussel (Comps and Tigé, 1999), the European flat oyster Ostrea edulis (Comps et al, 1977;Comps, 1985b) and the wedge clam Donax trunculus (Comps, 1985a); in Chile, infecting the Chilean mussel Mytilus chilensis (Lohrmann et al, 2019) and the Peruvian scallop Argopecten purpuratus (Lohrmann et al, 2002;Lohrmann, 2009); in Norway, infecting the European flat oyster (Mortensen, 1993); in Italy, infecting the wedge clam (Carella et al, 2019); and in New Zealand, infecting the Pacific oyster Crassostrea gigas and the dredge oyster Ostrea chilensis (Hine, 1997(Hine, , 2000Diggles et al, 2002). In these reported cases, no host inflammatory response was observed and the severity of the lesions associated with the IMC infection was mild.…”