A STUDY OF THE LIFE HISTORY OF TRICHOBILHARZIA CAMERONI SP. NOV. (FAMILY SCHISTOSOMATIDAE)

Abstract

A cause of swimmer's itch in the lower Ottawa River is Trichobilharzia cameroni sp. nov. Its life cycle has been completed experimentally in laboratory-bred snails and in canaries and ducks, and the various stages are described. The eggs are spindle-shaped. The sporocysts are colorless and tubular. Mother sporocysts become mature in about a week. The younger daughter sporocyst is provided with spines on the anterior end and becomes mature in about three weeks. The development in the snail requires from 28 to 35 days. A few cercariae were found to live for up to 14 days at 50 °C., although their life at 16° to 18 °C. was about four days. Cercariae kept at room temperature for 60 to 72 hr. were found infective. The adults become mature in canaries and pass eggs in about 12 to 14 days. Physa gyrina is the species of snail naturally infected. It was found in one case giving off cercariae for five months after being kept in the laboratory. Domestic ducks were found to become infected until they were at least four months old, with the parasites developing to maturity in due course; no experiments were made with older ducks. Furthermore, miracidia were still recovered from the faeces four months after the duck had been experimentally infected, and it is suggested that migratory birds are the source of the local infection.

The life-cycle and morphology of Trichobilharzia australis n.sp. (Digenea: Schistosomatidae) from the nasal blood vessels of the black duck (Anas superciliosa) in Australia, with a review of the genus Trichobilharzia

“…Only Physella gyrina, the normal host, became infected. Wu (1953) could not infect lymnaeid snails with miracidia of T. cameroni, a species utilizing Physa gyrina as intermediate host. Kawanaka (1978) reported that miracidia he attributed to T. brevis would develop in L. ollula but not in L. japonica.…”

“…Cercariae have been shown to develop to adulthood in a range of unrelated bird species. Adults of T. elvae and of T. cameroni were raised experimentally in canaries, domestic ducks and pigeons (McMullen & Beaver, 1945;Wu, 1953), of T. physellae in canaries, mallards and pigeons (McMullen & Beaver, 1945), of T. oregonensis in domestic ducks and geese (Macy et al, 1955) and of T. corvi in chickens (Ito, J., 1960). Schistosomula of T. brevis were found in the lungs of a white mouse exposed to cercariae a few days earlier (Basch, 1966).…”

“…Similarly, eggs of T. physellae which utilizes physid snails resemble those of T. maegraithi which develops in lymnaeid snails. Wu (1953) considered eggs to be important in species identification, but reported that the eggs of T. cameroni are rather variable in shape and swell after being laid. Neuhaus (1952a) observed that the egg of T. szidati attains its full length within the uterus, but only reaches its full width after being laid.…”

“…On the basis of this evidence, we consider that T. querquedulae is distinct from T. physellae and that its use of a physid snail as an intermediate host is likely but remains to be proved. Wu (1953), Farley (1971) and Turner & Threlfall (1975) also regard these species as separate. T. querquedulae stands apart from 7".…”

The emergence of cercariae of Trichobilharzia ocellata and its relationship to the activity of its snail host Lymnaea stagnalis

“…C. ocellata in Europe is said to emerge in the middle of the day (Vogel 1930) and Macy et al (1955) noted that, under outdoor conditions, Lymnaea stagnalis produced cercariae of Trichobilharzia elvae "in the morning." Wu (1952) concluded that T. cameroni emerged at variable times and that "there is no definite time for the cercariae to emerge." Further studies on T. brevis (Basch 1966) (Bearup 1956), Cercaria longicauda (MacFarlane 1949), and others do not permit a generalized statement to be drawn about the emergence behaviour of cercariae of bird schistosomes.…”