Weissellosis in rainbow trout in Colombia

Abstract

Weissellosis is an emergent disease caused by Weissella, a Gram-positive bacteria correlated with hemorrhagic illness and mortality in farm-raised trout in several countries. The current study reports the first outbreaks of weissellosis by Weissella ceti in rainbow trout (Oncorhynchus mykiss), which caused severe mortalities in trout farms in Colombia between May 2016 to June 2019. The disease occurred in several farms irrigated by the same river where temperatures were above 17 °C. Symptoms of the disease were limited almost exclusively to trout above 250 g. The clinical signs consisted of lethargic and anorexic fish, swimming in circles at the surface or against the walls. Pathological findings were mainly ocular lesions like bilateral exophthalmia, periocular and intraocular hemorrhage, lenticular opacity and corneal rupture usually leading to blindness, muscular hemorrhages and necrosis. Microbial isolating from eye, brain, kidney, liver and muscle was performed and W. ceti was confirmed by amplification and sequencing of the 16S rRNA. The aim of this work was to characterize the Weisellosis by Weissella ceti in trouts in Colombia, including microbiological isolating, molecular analysis, gross and microscopic characterization.

The Weissella and Periweissella genera: up-to-date taxonomy, ecology, safety, biotechnological, and probiotic potential

“…From 2015 to date, further cases have occurred, all involving W. confusa strains ( Table 4 ). As for Weissella infections in animals from 2015 to date, only five cases have been reported, with W. ceti as the etiological agent of weissellosis in rainbow trouts (Castrejón-Nájera et al, 2018 ; Mitomi et al, 2018 ; Medina et al, 2020 ; Vásquez-Machado et al, 2020 ).…”

Enfermedades bacterianas y sus agentes etiológicos identificados en peces de México - Una Revisión

“…El primer reporte de weissellosis se describió en China en 2007 (34), registrando pérdidas de hasta 40% en truchas adultas con signología septicémica. Posteriormente se describió en Brasil (33), también con manifestación septicémica en truchas adultas, y cuadros similares han sido informados en los Estados Unidos de Norteamérica, Japón y Colombia (34,35), México (10), Canadá, Sudáfrica y Perú (35).…”