Transmission Of SVCv
The rhabdovirus that causes SVC enters the fish through
the gills, replicating in gill epithelium and spreading to
internal organs (Ahne 1978; Baudouy et al. 1980). The virus
is distributed to other susceptible fish via mucoid casts in
feces from infected fish. Blood-sucking parasites, including
leeches and the fish louse Argulus, have been implicated
in spreading the disease (Pfeil-Putzien 1977; Ahne 1985).
Mechanical transmission by aquatic animals, birds, and
equipment is suspected because of the longevity of the virus
in water and mud and following desiccation (Ahne 1982a;
Ahne 1982b). The virus can survive freezing for one month
at -20°C (-4°F); thus, frozen infected fish that are fed to
piscivorous fishes or other animals may spread the virus to
other locations (OIE 2015a).