PENTASTOMIDA

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PENTASTOMIDA

The pentastomids comprise a small group of organisms that have a worm-like adult and a larval stage within the eggshell that appears to be mite-like. It appears that they are probably related in some way to the parasitic crustacea and have developed in a manner that allows them to live within the respiratory tract of vertebrates. Typically, the final host is a carnivorous vertebrate that becomes infected by eating an intermediate host that has larvae encysted in its viscera. Cats can become infected either by the ingestion of eggs, when they will serve as intermediate hosts supporting the larval stage internally, or they can get infected by eating an intermediate host, and then if the correct species of pentastomid is involved, they will develop infections of the upper respiratory system.

Adult pentasomes, have a mouth surrounded by four hooks; these were described initially as five mouths and hence the names. In veterinary medicine, pentastomes are most commonly seen in the air sacs of snakes (because these structures are transparent and thin, the location in the host is often misidentified as the body cavity) and encysted as larvae in the viscera of primates. The adults in snakes and the larvae in primates can be quite large several inches or more in length, so their discovery can be highly disconcerting.

The reports of pentastomiasis in cats have described the infection of the cats with the larval stage. These reports have come from Central Africa (Graber et al., 1973; Moens & Tshamala, 1986; Mohammed, 1972), India (Gretillat & Thiery, 1960), and Malaysia (Chooi et al., 1982). The cases have all dealt with infections of larval Armilliferarmillatus. The adults of this pentastome are found in the lungs and airsacks of large snakes.

The cases in cats have either been incidental findings or cats tht have presented with signs of abdominal disease, e.g., vomiting, anorexia, depression, and cachexia. The nymphs that are recovered tend to be yellowish-white in color and are about 1 to 2 cm long. The larvae have a thick stocky body that has psuedosegmentation that gives them a maggot-like appearance. The larvae are usually found in a coiled body position, looking like a “C” or a circle that is firmly attached to the omentum, or surfaces of various abdominal organs such as the liver, spleen, or kidney. To date, there has been no treatment attempted other than the surgical removal of the larvae.

REFERENCES

Chooi KF, Omar AR, Lee JYS. 1982. Melioidosis in a domestic cat, with concurrent infestation by nymphs of the cat pentastome, Armillifermoniliformis. Kajian Veterinar 14: 41-43.

Graber M, Troncy PM, Thal J. 1973. Prsence de larves d’Armilliferarmillatus Wyman, 1847 chez divers mammifres domestiques et sauvages d’Afrique Centrale. Bull Soc Pathol Exot 66:183-191.

Gretillat S, Thiery G. 1960. Porocephalose a Nettorhynchus (Armillifer) armillatus (Wyman 1845) chez un cat. Rev Elev Med Vet Pays trop 13:305-308.

Moens Y, Tshamala M. 1986. Nymphal pentastomiasis in a cat. Vet Rec. 119:44.

Mohammed AN. 1972. A note on the occurrence of Armilliferarmillatus (Wyman, 1845) (Phylum: Pentastomida, Order Porocephalida) in a cat. Nigerian J Sci 6:139-142.

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