Echinochasmus perfoliatus

Echinochasmus perfoliatus (Ratz, 1908)

(Figure 2-12)

ETYMOLOGY:Echino (Spined) + chasmus (hiatus) [for the discontinuous spination] and per (= extremely) + foliatus (= leaf-like)

SYNONYMS:Echinostomum perfoliatum Ratz, 1908; Echinochasmus perfoliatus var. shieldsi Tubangui, 1922; Echinochasmusperfoliatus var. japonicus Tanabe, 1922; Echinochasmus perfoliatus var. aegyptius Fahmy et al., 1981.

HISTORY: This worm was originally described from dogs and cats in Hungary (Ratz, 1908). Further work has shown it to be present in cats in Russia and Asia.

GEOGRAPHIC DISTRIBUTION: This trematode is a common parasite of cats in Italy, Hungary, Romania, Russia, Egypt, Israel, and the Far East (Wu, 1938; Fahmy et al., 1981; Fahmy, et al., 1984; Abo-Shady, et al., 1983).

LOCATION IN HOST: Small intestine.

PARASITE IDENTIFICATION: This worm is elongate, measuring 1 to 12 mm in length. The genus Echinochasmus is characterized by the possession of a single row of typical Echinostomatid hooks on the anterior collar. Echinochasmus differs from other genera of Echinostomes in that this circle of hooks is discontinuous in both the ventral and dorsal aspects of the body. The testes are large, globose structures that occur in tandem just posterior to the midline of the body. The ventral sucker is located at the beginning of the second third of the body.

The eggs are rather large, being 90 to 135 µm long by 55 to 95 µm in width.

LIFE CYCLE: Cats have been experimentally infected by feeding them fish containing metacercariae (Ciurea, 1922). The snail intermediate hosts are species of the fresh-water genus Parafossarulus. The cercariae are of the echinostome type, i.e., they have a tail that is not forked, oral and ventral suckers, and small hooks similar to those of the adult arranged in a row on the head collar. The cercariae enter fish by being swept into the pharynx, and the metacercariae are found encysted in the gills of numerous different fresh-water fish. The adult forms develop within 7 to 10 days after the fish is eaten.

CLINICAL PRESENTATION AND PATHOGENESIS: Thought to be asymptomatic.

TREATMENT: Probably praziquantel, but not reported.

EPIZOOTIOLOGY: Cats become infected by eating raw 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 infected with this trematode. It is believed the infection is less common in people than might otherwise be the case due to the large number of infected fish because of the location of the metacercariae in the gill tissue of the fish host which is often discarded when the fish is eaten.

CONTROL/PREVENTION: Prevention of the ingestion of raw fish heads.

REFERENCES:

Abo-Shady AF, Ali MM, Abdel-Magied S. 1983. Helminth parasites of cats in Dakahlia, Egypt. J Egypt Soc Parasitol 13:129-133.

Ciurea I. 1922. Sur quelques trématodes de renard et du chat sauvage. Comptes Rendus Soc Biol. 87:268-299.

Fahmy MA, Khalifa R, Sakla AA. 1981. Study of two echinochasmid parasites (Trematoda: Echinochasmidae) from Upper Egyptian cats. Assiut Vet Med J 8:73-75.

Fahmy MA, Arafa MS, Khalifa R, Abdel-Rahman AM, Mounib ME. 1984. Studies on helminth parasites in some small mammals in Assiut Governorate. 1. Trematode Parasites. Assiut Vet Med J 11:43-52.

Wu K. 1938. Helminthic fauna of in vertebrates of the Hangchow area. Peking Nat Hist Bull 12:1-8.

FIGURE 2-12.Echinochasmusperfoliatus collected from a cat in Egypt.

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