Parasitology



Risk factors associated with Enteromyxum scophthalmi (Myxozoa) infection in cultured turbot, Scophthalmus maximus (L.) 1


M. I. QUIROGA a2, M. J. REDONDO a1, A. SITJÀ-BOBADILLA a1, O. PALENZUELA a1, A. RIAZA a3, A. MACÍAS a3, S. VÁZQUEZ a2, A. PEREZ a4, J. M. NIETO a2 and P. ALVAREZ-PELLITERO a1c1
a1 Instituto de Acuicultura Torre de la Sal (C.S.I.C.), Ribera de Cabanes, 12595 Castellón, Spain
a2 Departamento de Ciencias Clínicas Veterinarias, Universidad de Santiago, Campus Universitario, 27002 Lugo, Spain
a3 Stolt Sea Farm S.A., Lira, Carnota
a4 Center for Animal Diseases Modeling and Surveillance, University of California in Davis, 279 Cousteau Place, Suite 500, Davis, CA 95616, USA, and CONICET/INTA Balcarce, Grupo de Sanidad Animal, Ruta 226 km 73, (7620) Balcarce, Argentina

Article author query
quiroga mi   [PubMed][Google Scholar] 
redondo mj   [PubMed][Google Scholar] 
sitja-bobadilla a   [PubMed][Google Scholar] 
palenzuela o   [PubMed][Google Scholar] 
riaza a   [PubMed][Google Scholar] 
macias a   [PubMed][Google Scholar] 
vazquez s   [PubMed][Google Scholar] 
perez a   [PubMed][Google Scholar] 
nieto jm   [PubMed][Google Scholar] 
alvarez-pellitero p   [PubMed][Google Scholar] 

Abstract

An epidemiological cohort study of Enteromyxum scophthalmi in cultured turbot was performed on a farm in North Western Spain. Four different ongrowing stocks (A, B, C, D) were monitored monthly until market size. Fish from stocks C and D were divided into 2 subgroups, receiving filtered (CF and DF) or unfiltered (CUF and DUF) water. The lack of water filtration was positively associated with infection prevalence, as all fish kept in filtered water remained uninfected. Parasite abundance varied seasonally (P<0·05) in stock B and subgroup CUF. Infection was also associated (P<0·05) with host weight, and the highest prevalences and intensities were detected in 101–200 g and 201–300 g fish. Distribution pattern of E. scophthalmi in subgroups CUF and DUF had a variance higher than the mean, indicating overdispersion. The minimum period necessary for the first detection of the parasite and for the appearance of disease symptoms and mortality, varied depending on the stock and introduction date, although a long pre-patent period was always observed. Several factors, such as host density, parasite recruitment and parasite-induced fish mortality can contribute to the observed distribution pattern. Risk factors found to be associated with E. scophthalmi infection, including water quality and accumulation of infective stages in the culture tanks, should be considered when designing control strategies to prevent the introduction and spread of infective stages in the facilities.

(Received February 10 2006)
(Revised April 11 2006)
(Accepted April 13 2006)
(Published Online June 19 2006)


Key Words: epidemiology; Myxosporea; aquaculture; fish; enteromyxosis.

Correspondence:
c1 Instituto de Acuicultura Torre de la Sal (C.S.I.C.), 12595 Ribera de Cabanes, Castellón, Spain. Tel: +34 964 319500. Fax: +34 964 319509. E-mail: alvarezp@iats.csic.es


Footnotes

1 M. I. Q and M. J. R. contributed equally to this article, so they share first authorship.



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