Host and environmental risk factors associated with Cryptosporidium scophthalmi (Apicomplexa) infection in cultured turbot, Psetta maxima (L.) (Pisces, Teleostei)

• Published in: Veterinary Parasitology
• Main Authors: Álvarez-Pellitero, Mª del Pilar, Pérez, Andrés M., Quiroga, María Isabel, Redondo, Mª José, Vázquez, Sonia, Riaza, Ana, Palenzuela, Oswaldo, Sitjà-Bobadilla, Ariadna, Nieto, José M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2009
• Subjects: Epidemiology; Multivariable regression model; Aquaculture; Fish; Turbot
• Online Access: http://hdl.handle.net/10261/46171; https://doi.org/10.1016/j.vetpar.2009.07.024

37 p., 8 figuras, 3 tablas y bibliografía An epidemiological cohort study of Cryptosporidium scophthalmi in cultured turbot Psetta maxima L. of Northwestern Spain was conducted along a four-year period. Four different ongrowing cohorts were monitored monthly from introduction into the ongrowing tanks (10-50 g) until reaching market size (400-1400 g). The association of host and environmental factors with five categories of parasite abundance was assessed using a multivariable regression framework. Epidemiological factors assessed here were water temperature, weight, length, month of collection, season, age, origin, condition factor, water filtration, and status to the myxozoan Enteromyxum scophthalmi infection. E. scophthalmi was included into the analysis because it targets the same organ than C. scophthalmi and it was prevalent in the studied population. The multivariable analysis demonstrated the statistically significant association between several factors and parasite abundance. C. scophthalmi abundance was associated (P < 0.05) with age, condition factor, season, and status to E. scophthalmi infection. Young animals, with poor condition factor, during spring or summer, and not infected with the myxozoan were most likely to be highly infected by C. scophthalmi. Inclusion of these four variables significantly (P < 0.05) improved the model, compared to the model that did not include any of these epidemiological factors. Increasing levels of C. scophthalmi abundance were associated (P < 0.01) with higher severity of C. scophthalmi-compatible lesions. The frequency of distribution of C. scophthalmi abundance was clearly right-skewed and fitted a negative binomial distribution, whereas the intensity of infection fitted a Poisson distribution. The quantification of the variance-to-mean ratio stratified by age demonstrated overdispersion for 8-16 months old fish, although this bivariate association is likely affected by several other factors, as suggested by the results of the multivariable analysis. ...