Cryptobia (Trypanoplasma) salmositica is a haemoflagellate that causes
morbidity and mortality in salmon, Oncorhynchus spp, on the Pacific c
oast of North America, In this review, Patrick Woo briefly describes t
he pathogen, its transmissions (either indirectly via its leech vector
, Piscicola salmositica, or directly between fish) and the clinical si
gns of the disease. He then outlines strategies that have been develop
ed to protect fish against the pathogen, and the mechanism of innate r
esistance to disease in Cryptobia-tolerant fish. Protective strategies
include the breeding of fish that are resistant to infection, and the
use of an attenuated C. salmositica strain to protect susceptible fis
h from disease for at least two years. He ends the review with suggest
ions for further research that include the use of the leech vector to
deliver the vaccine and the development of more novel protective strat
egies (eg. immunochemotherapy, anti-idiotype vaccine) against cryptobi
osis.