Haplorchis sprenti Pearson, 1964

ETYMOLOGY:Haplorchis = single testis and sprenti = for Dr. Sprent


HISTORY: This fluke was originally described from specimens collected from a water rat (Hydromys chryogaster), a domestic cat, a little black cormorant (Phalacrocorax ater), a little pied cormorant (Phalacrocorax melanoleucus), a pied cormorant (Phalacrocorax sulcirostris), a pelican (Pelecanus conspicillatus), and herons and egrets.

GEOGRAPHIC DISTRIBUTION: This trematode is found in Australia.

LOCATION IN HOST: Small intestine.

PARASITE IDENTIFICATION:Haplorchis sprenti is very similar to Haplorchis yokogawai. It differs mainly in the shape of the body, being pyriform with the length being 0.25 to 0.42 mm, and the width being 0.08 to 0.12 mm anteriorly and 0.09 to 0.17 mm posteriorly. The eggs measure 27 to 32 µm by 13 to 15.5 µm, and contain a fully developed miracidium when laid.

LIFE CYCLE: The life cycle has elucidated by the feeding of infected brackish-water fish to cats, rats, and chickens (Pearson, 1964).

CLINICAL PRESENTATION AND PATHOGENESIS: Not reported but thought to be asymptomatic.

TREATMENT: Probably praziquantel, but not reported.

EPIZOOTIOLOGY: Cats become infected by eating raw fish. Other hosts that ingest infected raw fish are also likely to become infected. The normal natural hosts are probably piscivorous birds.

HAZARD TO OTHER ANIMALS: None known; however, due to the requirements for two intermediate hosts, it is unlikely that an infected cat would pose a direct threat to other animals.

HAZARD TO HUMANS: Humans could be infected by the ingestion of the infected fish intermediate hosts.

CONTROL/PREVENTION: The prevention of the ingestion of raw fish.


Pearson JC. 1964. A revision of the subfamily Haplorchiinae Looss, 1899 (Trematoda: Heterophyidae). Parasitology 54:601-676.