Clinostomum falsatum Ortlepp, 1963
ETYMOLOGY:Clino (bent) + stoma (mouth) and falsatum for bill-hooked.
HISTORY: This parasite was described from the oral mucosa of a cat in Durban, South Africa. A second collection of similar specimens was made from the mouth of a cat in Lydenburg.
GEOGRAPHIC DISTRIBUTION: South Africa.
LOCATION IN HOST: Mouth.
PARASITE IDENTIFICATION: These are small trematodes that are less than 5 mm long. The oral sucker, which is retractable as evidenced by a collar-like fold in the tegument of the fluke at the base of the oral sucker, is about one-third the diameter of the ventral sucker that is located slightly anterior to midbody. The genital opening is posterior to the ventral sucker, and the ovary is in the posterior of the body between the testes.
The oval eggs are large, 95-116 µm long by 65-74 µm wide, operculate, and not embryonated when they leave the fluke.
LIFE CYCLE: The life cycle of Clinostomumfalsatum has not been elucidated. Other Clinostomatids are typically found as adults in the mouth or esophagus of aquatic reptiles and birds. Miracidia develop in eggs that leave the bird and in the water the miracidia hatch and penetrate a snail host. After sporocyst and redial generations, brevifurcate, pharyngeate cercariae with pigmented eye spots are produced. These cercariae seek out fresh-water fish which they penetrate and then encyst as metacercariae in muscle and connective tissues. The metacercaria contains some reproductive structures and takes only a few days to develop to the adult stage after a fish is eaten by a final host.
CLINICAL PRESENTATION AND PATHOGENESIS: The clinical presentation has been described by Dr. Coetzee (in Ortlepp, 1963) as follows: "An Indian resident at Badfontein brought in a male domestic cat in fairly good condition with the information that it had worms in its mouth.” Subsequent examination revealed a granulomatous growth in the soft tissues (frenulum) under the tongue. The parasites were firmly attached within the growth and required removal with forceps.
TREATMENT: Physical removal.
EPIZOOTIOLOGY: Cats become infected by eating fish containing the metacercariae. The flukes are capable of developing to the adult stage in a few days.
HAZARD TO OTHER ANIMALS: None.
HAZARD TO HUMANS: None.
CONTROL/PREVENTION: Prevent cats from eating raw fish.
Ortlepp RJ. 1963. Clinostomid trematodes as aberrant parasites in the mouth of the domestic cat (Felis catus domesticus). Onderstepoort J Vet Res. 30:137-144.