Centrocestus caninus Leiper, 1913
ETYMOLOGY:Centro (spined) + cestus (girdle) [for a ring of small spines around the oral opening] and caninus for the canine host
SYNONYMS:Centrocestus cuspidatus Leiper, 1913; Stephanopirumus longus Onji and Nishio, 1916; Stamnosoma formosanum Nishigori, 1924; Centrocestus yokogawai Kobayasi, 1942.
HISTORY: This parasite was first described by Leiper from a dog in Taiwan (Leiper, 1913).
GEOGRAPHIC DISTRIBUTION: This parasite has been reported from Egypt, the islands of Taiwan and Hainan, and from Malaysia (Chen, 1941, and Rohde, 1962).
LOCATION IN HOST: Small intestine.
PARASITE IDENTIFICATION: This small worm has two rows of spines (a total of 30 to 36 spines) on the oral sucker. The testes are terminal and the vitellaria do not extend into the middle of the body.
The eggs are 33 µm long by 16 to 17 µm in width; the eggs are relatively thin shelled and bear minute spines.
LIFE CYCLE: The life cycle has been examined by Nishigori (1924) and Chen (1941). The miracidia develop in snails of the genus Semisulcospira, and the simple-tailed cercariae with eyespots encyst in the gills of various fresh-water fishes, including Macropodus opervularis, Puntius semifasciolatus, Carassius auratus, and Misgurnus anguillicaudatus, and in the stomach wall and muscle of frogs, Rana limnocharis and toads, Bufo melanostictus. When cats were experimentally infected, eggs were present 11 to 17 days after the cats were fed metacercariae.
CLINICAL PRESENTATION AND PATHOGENESIS: Thought to be asymptomatic.
TREATMENT: Probably praziquantel, but not reported.
EPIZOOTIOLOGY: Cats become infected by eating raw fish or frogs. Animals other than the cat that have been shown to serve as hosts of the adult fluke include the various herons and egrets. Man and dogs have been experimentally infected through the feeding of infected fish.
HAZARD TO OTHER ANIMALS: None. Although other hosts are infected, the major means of infection is through the ingestion of the fish intermediate host which requires that the appropriate snail also be available. Thus, infection of these other hosts will typically only occur in the wild.
HAZARD TO HUMANS: Humans have been experimentally infected by feeding them fish containing the metacercarial stage of this parasite.
CONTROL/PREVENTION: Prevention of the ingestion of raw fish.
REFERENCES:
Chen HT. 1941. The metacercaria and adult of Centrocestusformosanus (Nishigori, 1924), with notes on the natural infection of rats and cats with C. armatus (Tanabe, 1922). J Parasitol 28:285-298.
Leiper RT. 1913. Seven helminthologial notes. J Lond School Trop Med 2:175-178.
Nishigori M. 1924. On a new species of fluke, Stamnosomaformosanum, and its life history. Taiwan Igakkai Zasshi 234:181-238.
Rohde K. 1962. Helminthen aus Katzen und Hunden in Malaya; Bemerkungen zu ihrer epidemiologischen Bedeutung für den Menschen. Z Parasitenk 22:237-244.