ACANTHOCEPHALA
The acanthocephala is a small phylum of worm-like creatures that is very important relative to fish, aquatic reptiles, and aquatic birds. There are a few that have developed life cycles that allow them to make good use of terrestrial hosts, but for the most part, they are seen almost exclusively by individuals working in wildlife biology or medicine.
The adult worms can reach in size from less than 1 cm to more than 35 cm in length depending on the species involved. The adult worms do not have an intestinal tract, and on the anterior end of the worm, there is a protrusible proboscis that is covered with hooks. The adult worms are all parasites of the intestinal tract where they live with their proboscis embedded in the intestinal mucosa. There are separate sexes, males and females, and the females produce eggs that are characteristic in that they typically have three marked components to the shell and have a larva inside that has a lot of hooklets on one end. In the typical life cycle, there is the requirement for some type of arthropod as the first intermediate host. Depending on the species, the life cycles can also involve various paratenic vertebrate hosts. When cats become infected, they have typically done so by eating either an intermediate host or a vertebrate paratenic host.
The majority of reports of acanthocelphala in cats have come from Australia (O’Callaghan & Beveridge, 1996; Thompson et al., 1993; Shaw et al., 1983; Coman et al., 1981; Ryan 1976; Coman 1972). Almost all these reports have dealt with cats being infected with a species of Oncicola. In the most recent of these reports (O’Callaghan & Beveridge, 1996), the species in the cats from the Northern Territory of Australia were identified as Oncicola pomatostomi. In the 188 cats that were examined in this study, this was the most common helminth recovered being present in over 65% of the cats, and infected cats had anywhere from 1 to 1,000 worms. In the other studies, the prevalence of infection was lower. Cats probably acquired infections with this acanthocephalan through the ingestion of a paratenic host. The arthropod intermediate host has not been described, but birds and small mammals can probably serve as paratenic hosts.
In most cases, the acanthocephala parasite has not been identified to genus yet alone to species. In Somalia, a cat was reported as being infected with a species of Moniliformis, which is typically found in rodents and which uses an arthropod as the intermediate host (Gadale et al., 1989). Reports from Japan (Asato et al., India (Balasubramaniam, 1972); Malaysia (Amin-Babjee, 1978); and Chile (Bonilla-Zepeda, 1980) have simply reported the presence of these worms. Chandler (1925) recorded Centrorhynchus erraticus from a cat in Calcutta.
REFERENCES
Amin Babjee. 1978. Parasites of the domestic cat in Selangor, Malaysia. Kajian Vet 10: 107-114.
Asato R, Hasegawa H, Kuniyoshi S, Higa T. 1986. Prevalence of helminthic infections in cats on Okinawa Island, Japan. Jap J Parasitol 35: 209-214.
Balasubramaniam G. 1972. Report of an acanthocephalan infection in a domestic cat (Felisdomesticus). Cheiron 1:116-117.
Bonilla-Zepeda C. 1980. Estudio de la fauna helmintologica del gato en la ciudad de Valdivia, Chile. Arch Med Vet 12: 277.
Chandler AC. 1925. The helminthic parasites of cats in Calcutta and the relation of cats to human helminthic infection Ind J Med Res 13:213.
Coman BJ. 1972. A survey of the gastro-intestinal parasites of the feral cat in Victoria. Austral Vet J 48:133-136.
Coman BJ, Jones EH, Driesen MA. 1981. Helminth parasites and arthropods of feral cats. Austral Vet J 57: 324-327.
Gadale OI, Capelli G, Ali AA, Poglayen G. 1989. Intestinal helminths of cats. First reports in Somalia. Bollett Sci Fac Zootec Vet Univ Naz Somala 1989: 8-24.
O’Callaghan MG, Beveridge I. 1996. Gastro-intestinal parasites of feral cats in the Northern Territory. Trans Roy Soc S Australia 120: 175-176.
Ryan GE. 1976. Gastro-intestinal parasites of feral cats in New South Wales. Austral Vet J 52:224-227.
Shaw J, Dunsmore H, Jakob Hoff, R. 1983. Prevalence of some gastrointestinal parasites in cats in the Perth area. Austral Vet J 60: 151-152.
Thompson RCA, Meloni BP, Hopkins RM, Deplazes P, Reynoldson JA. 1993. Observations on the endo- and ectoparasites affecting dogs and cats in Aboriginal communities in the north-west of Western Australia. Austral Vet J 70:268-270.