Diplopylidiumacanthotetra (Parona, 1886) Witenberg, 1932
ETYMOLOGY:Diplo = double and pylidium = openings along with acantho = spined and tetra -four rows of hooks.
SYNONYMS: Witenberg (1932) reviewed the genus Diplopylidium, and he recognized four species of which only two were considered as parasites of the domestic cat. The synonyms he recognized were: Diplopylidiumfabulosum Meggitt, 1927; Diplopylidiumquinquecoronatum (Lopez-Neyra & Munoz-Medina, 1921); Diplopylidiumtrinchesii (Diamare, 1892); Diplopylidiumtriseriale (Lühe, 1898).
HISTORY: The genus Diplopylidium was first described by Beddard in 1913 who noted the character of the genus, that is in that the openings of the male reproductive system are behind the openings of the female reproductive system. The species Diplopylidiumacanthotetra was first described as a larval stage from a lizard, Zamensisviridiflavus, in Italy by Parona. Later the adult stage was found by Diamare, 1892 who described it as Dipylidiumtrinchesii but thought it to be the same species as that described as acanthotetra. Later work on the life cycle convinced Witenberg that these were the same species.
GEOGRAPHIC DISTRIBUTION:Diplopylidiumacanthotetra have been reported from the Middle East, North Africa, and southern Europe (Daoud et al., 1988; El-Shabrawy & Imam, 1978; Harralampidis, 1977; Ismail et al., 1983; Roca & Lluch, 1988; Witenberg, 1932). In Egypt, El-Shabrawy & Imam (1978) reported that 51 out of 66 cats were host to cestode parasites, 22.5% harbored a single species, 45.1% had tow species, while 32.4% were reported with three or more types of tapeworms: Diplopylidiumacanthotetra was found in 16 cats (24.2%); Diplopylidiumnölleri was found in 24 cats (36.4%); Joyeuxiellapasqualei was found in 21 cats (31.8%); Dipylidiumcaninum was found in 30 cats (45.5%); and Taeniataeniaeformis was found in 20 cats (30.3%).
LOCATION IN HOST: The adult Diplopylidiumacanthotetra is in found in the small intestine of the feline host.
IDENTIFICATION: When compared to Dipylidium and Joyeuxiella species, Diplopylidium is in the smallest, only 4-12 cm, of these types of tapeworms found in the cat. It holdfast possesses four suckers and a retractable rostellum armed with thorn-like hooks. The proglottids are shaped like cucumber seeds, possessing two complete sets of genital organs and bilateral genital pores. The genital pores of Diplopylidium lie anterior to the middle of the proglottid. Each egg capsule contains a single egg. Diplopylidiumacanthotetra is in characterized by having a short neck and hooks on the scolex that are larger than those of Diplopylidiumnölleri.
LIFE CYCLE: Very little has been described relative to the biology of this parasite. The cat sheds segments into the environment which contain eggs that are infectious. It is in believed that the first intermediate host is in some form of coprophagous insect, but this has never actually been proven for any member of this genus. The second intermediate hosts are cysticercoids (small solid-bodied tapeworm larvae with an inverted scolex) that are found in reptiles. Cats become infected by the ingestion of the second intermediate host. Parrot and Joyeux (1920) fed cysticercoids to three cats and two became infected. Tapeworms recovered 14 days after the feeding of the cysticercoids contained mature but no gravid proglottids. Tapeworms recovered 22 days after the feeding of the cysticercoids contained gravid proglottids.
CLINICAL PRESENTATION AND PATHOGENESIS: There have been no descriptions of signs in cats infected with this parasite, so it is thought to be asymptomatic.
DIAGNOSIS: Little has been described on the actual diagnosis of infection with this tapeworm other than at necropsy. It would seem likely that proglottids are passed in the feces of the cat as occurs with Dipylidium, and it may bee that occasionally free egg capsules containing a single egg may be observed in fecal samples. Each proglottid of Diplopylidium species possesses two genital pores for fertilization. The egg with its capsule is in best demonstrated by taking a gravid proglottid and teasing it open in a small amount of physiologic saline or tap water to disperse the characteristic egg capsule with its single egg (Georgi, 1987).
TREATMENT: Praziquantel (Droncit) administered at 25 mg per animal at 6-week intervals has proven to be effective against Joyeuxiella (Blagburn and Todd, 1986), a tapeworm in the same family as Diplopylidiumacanthotetra
EPIZOOTIOLOGY: Cats become infected by ingesting reptiles in dwellings and yards.
HAZARDS TO OTHER ANIMALS: Adult Diplopylidiumacanthotetra has also been reported from civets.
HAZARDS TO HUMANS: The authors were unable to ascertain any public health significance potential similar to that which would be observed with Dipylidiumcaninum.
CONTROL/PREVENTION: Cats should not be allowed to roam freely or to scavenge carcasses. Predation may lead to infection with Diplopylidiumacanthotetra if prey animals or carcasses containing cysticercoids.
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