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University of Veterinary Medicine, Vienna
RNA interference (RNAi) as a possible control
of whirling disease in rainbow trout
(Oncorhynchus mykiss)
Postdoctoral fellowship PD0112, Mansour El-Matbouli
Abstract
Whirling disease caused by the myxosporean agent, Myxobolus cerebralis, is considered not
only a problem in the European Aquaculture but also a major threat to the survival of wild
rainbow trout (Oncorhynchus mykiss) in North America (El-Matbouli et al. 1999a, Hedrick & ElMatbouli 2002, Hedrick et al 2003). The life cycle of M. cerebralis alternates between two hosts:
Salmonid fish and aquatic the oligochaetes Tubifex tubifex (El-Matbouli et al. 1999b). After a
three-phase development in the intestinal epithelial tissue of the oligochaete, the triactinomyxon
stages of M. cerebralis are released into the water. These spores are infectious to the alternate
host, salmonids where it penetrate the epidermis of the fish, reach to the peripheral nerves and
migrate to the cartilage (El-Matbouli et al. 1995; El-Matbouli & Hoffmann 1998)). The disease
has three characteristic symptoms: whirling swimming behaviour, blackening of the caudal part
of the fish, and deformation of head and spinal column (Hedrick et al. 1998). As there is no
successful treatment to whirling disease up to now, affected fishes subjected to destruction. The
development of an effective control and prevention method will diminish the economic losses in
salmonid fish due to whirling disease.
RNA interference (RNAi) is a technique in which exogenous double-stranded RNAs, that are
complimentary to known mRNA, are introduced into a cell to specifically destroy that particular
mRNA, thereby diminishing or abolishing gene expression (Schyth et al. 2006). RNAi
technology was applied successfully not only with many parasites such as Caenorhabditis
elegans, human filarial nematode Onchocerca volvulus and Schistosoma mansoni, but also with
fish (Wargelius et al.1999; Dodd et al. 2004; Nasevicius & Ekker 2000), making RNAi a potential
therapeutic tool in veterinary medicine.
The aim of this project is to breakdown the M. cerebralis life cycle to control the whirling
disease. By using RNAi technology, important genes of M. cerebralis will be targeted by small
interfering RNA (siRNA) to hinder the development of the spores in the oligochaete host or to
down regulate the expression of genes important for spore’s pathogenesis to prevent it from
infection of rainbow trout and development of whirling disease.
Postdoctoral fellowship PD0112, Mansour El-Matbouli
03.09.2012
Seite 1/2
University of Veterinary Medicine, Vienna
References
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Postdoctoral fellowship PD0112, Mansour El-Matbouli
03.09.2012
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