Rl. Rausch et Am. Adams, Natural transfer of helminths of marine origin to freshwater fishes, with observations on the development of Diphyllobothrium alascense, J PARASITOL, 86(2), 2000, pp. 319-327
Infective stages of helminths of 5 species that occur as adults in marine m
ammals were found in burbot, Lota lota (L.) (Gadidae), from the lower Kusko
kwim River (southwestern Alaska): Diphyllobothrium alascense Rausch et Will
iamson, 1958; Pyramicocephalus phocarum (Fabricius, 1780); Corynosoma strum
osum (Rudolphi, 1801); Corynosoma semerme (Forsell, 1901); and Pseudoterran
ova decipiens (Krabbe, 1878). Some larval stages were obtained also from sm
elt, Osmerus mordax dentex Steindachner, an anadromous fish important as pr
ey of burbot. Burbot, which are freshwater fish, could become paratenic hos
ts of those helminths by means of at least 3 interactions: by consuming mar
ine fishes in brackish waters at river mouths, by feeding on marine fishes
that enter lower reaches of rivers, or by preying on anadromous fishes as t
hey migrate up livers. Consumption of burbot by people may result in infect
ion by helminths of marine origin; of those recorded, only P. decipiens may
be significantly pathogenic. Attempts to rear P. phocarum in dogs were uns
uccessful. Plerocercoids of D. alascense, of very small size and found only
in the gastric lumen of burbot, readily infected dogs. For study of their
development, strobilae were obtained at intervals of 48 hr to 32 days posti
nfection. In heavy infections, some strobilae developed slowly, while other
s underwent rapid development.