Transmission of the Hemoflagellate, Cryptobia salmositica Katz, 1951, by a Rhynchobdellid Vector

Abstract

The transmission of Cryptobia salmositica Katz, 1951, a hemoflagellate of freshwater teleosts, was investigated in experiments involving the rhynchobdellid leech, Piscicola salmositica Meyer, 1946. Uninfected leeches developed metacyclic stages of Cryptobia in their digestive tracts after feeding on naturally infected torrent sculpins (Cottus rhotheus). When naturally infected leeches were fasted and then allowed to engorge on uninfected juvenile coho salmon (Oncorhynchus kisutch) and torrent sculpins, parasitemias developed in the fish as early as 5 days after the leeches had fed. Infections did not appear in uninfected fish after ingesting infected leeches, nor in uninfected leeches after feeding on the blood of uninfected fish. C. lynchi Katz, 1951, is declared a synonym of C. salmositica. Aquatic leeches are recognized as vectors of Cryptobia (= Trypanoplasma) occurring in the blood of European freshwater fishes (Leger, 1904; Keysselitz, 1906; Brumpt, 1906, 1907; Robertson, 1912). Yet, as far as is known, there are no records of leeches as vectors of these hemoflagellates in freshwater teleosts of North America. Infections of Cryptobia salmositica Katz, 1951 (Mastigophora: Cryptobiidae) have been reported in adult and young salmonids and in sculpins of western Washington and Oregon (Katz, 1951; Davison et al., 1954; Katz et al., 1960, 1961). Similar, if not identical parasites, have also been found in various teleosts of northern California (Wales and Wolf, 1955). In the same general localities, the leeches, Piscicola salmositica Meyer, 1946 (Rhynchobdellae : Piscicolidae), are habitual ectoparasites of adult salmonids (Meyer, 1946, 1949; Earp and Schwab, 1954; Haderlie, 1953). Both the hemoflagellates and the leeches are apparently endemic to the Pacific coast of the North