Aonchotheca putorii

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Aonchotheca putorii (Rudolphi, 1819) López-Neyra, 1947

(Figure 4-59)

ETYMOLOGY: a = un + oncho = spined + theca = sheath (referring to the unspined sheathe on the spicule of the male) and putorii for the original isolation from a ferret.

SYNONYMS:Trichosomaputorii Rudolphi, 1819; Trichosomaerinacei Rudolphi, 1819; Trichosomumexigua Dujardin, 1845; Trichosomumentomelas Dujardin, 1845; Calodiumalatum Molin, 1858; Capillariaerinacea (Rudolphi, 1819) Travassos, 1915; Capillariamustelorum Cameron & Parnell, 1933; Capillariaputorii (Rudolphi, 1819) Travassos, 1915.

HISTORY:Aonchothecaputorii was first described by Rudolphi in 1819 as Trichosomaputorii from the stomach of a ferret, Mustelaputorius. Butterworth and Beverley-Burton (1980) felt that Capillariaerinacei of the European hedgehog and Capillariamustelorum of weasel in Scotland were synonymous with the species recovered from ferrets.

GEOGRAPHIC DISTRIBUTION:Aonchothecaputorii has been reported from domestic cats in Europe, North America, and New Zealand (Butterworth and Beverley-Burton (1980. Aonchothecaputorii is a common parasite of the stomach and small intestine of such wild mammals as bobcats, racoons, mink, and various other mustelids (Butterworth and Beverly-Burton, 1980; Campbell, 1991).

LOCATION IN HOST:Aonchothecaputorii is usually observed in the gastric mucus, but some descriptions note its occurrence in the small intestine. In the Iowa report, the parasites were found in the gastric mucus, but only on occasions where there had been intestinal reflux (Greive and Kung, 1983). Butterworth and Beverley-Burton (1980) found that the worms lived within the gastric mucosa and were easiest to identify in tissues when the mucosal surface was washed with 1% aqueous methylene blue which gave the tissues a light blue appearance and made the unstained worms easier to visualize.

IDENTIFICATION: Particular morphologic details of adult Aonchothecaputorii are influenced by the definitive hosts which they parasitize. In the feline, the male stomach capillarids range in size from 2.52 to 5.29 mm (average 3.97 mm); the females range in size from 3.46 to 7.40 mm (average 5.04 mm). The gastric capillarids recovered from cats in New Zealand were approximately 8 mm in length (Collins and Charleston, 1972). The width at the posterior end of the stichosome of the male is from 24 to 38 μm (average 29) while that of the female is from 24 to 38 μm (average 33.4). The maximum width of the male ranges from 31 to 41 μm (average 33); that of the female is 34 to 51 μm (average 41.4). The distance from the vulva to the anterior end in the female is 2.01 to 3.18 μm (average 2.48). The vulvar flap of Aonchothecaputorii may or may not be covered by a cuticular flap; instead, the vulva is surrounded by varying amounts of corrugation. The males demonstrate a characteristic structure of the tip of the spicule and a distinct form of the lateral and caudal alae (Greve and Kung, 1983). The spicule length in the male is from 162 to 276 μm with an average length of 211 μm. The characteristic of this genus which allows easiest identification of these worms is the lack of spices on the cirrus, or spicular sheathe, which surrounds the spicule.

The egg length of this capillarid is from 57 to 66 μm (average 61.3); the egg width is from 21 to 28 μm (average 23.3). The eggs are characterized by having a dark shell with thickened ridges on their surfaces (Fig. 4-59).

LIFE CYCLE: It has been postulated that the New Zealand cats became infected by ingesting infective eggs of Aonchothecaputorii from soil contaminated with hedgehog feces. These capillarids reach maturity in the stomachs of cats and dogs as well as in hedgehogs (Collins, 1973).

CLINICAL PRESENTATION AND PATHOGENESIS: Until the reports by Curtsinger et al. (1993), the pathogenicity of Aonchothecaputorii in domestic cats was not known (Greve and Kung, 1983). It had not been associated with clinical illness in cats in the United States, but a European report documented it as a cause of feline gastritis (Wagner, 1936).

There are few reports on the clinical presentation of infection in cats with this parasite. One domestic cat presented with a 3-week history of partial anorexia and intermittent passage of bloody vomitus and tarry feces (Curtsinger et al., 1993). . Physical examination revealed lethargy, dehydration, pale mucus membranes and signs of pain when the cranial portion of the abdomen was palpated. A complete blood cell count revealed a normocytic, normochromic anemia. Serum biochemistry tests revealed hyperglycemia, hypocalcemia, and hypokalemia. Multiple fecal examinations were negative. Contrast radiography revealed delayed gastric emptying. Exploratory laparotomy revealed a 0.5 cm diameter perforation in the caudal aspect of the pylorus. There were adhesions between the pylorus and the surrounding structures Histology of gastric tissue obtained by gastroduodenoscopy showed chronic, hyperplastic pyloric gastritis, dilation of numerous pyloric glands, regions of superficial mucosal fibrosis, and perforation of an ulcer in the caudal aspect of the pylorus. Adult nematodes, identified as Aonchothecaputorii, and their eggs were observed in the pyloric mucosa, near the perforation. The nematodes in tissue sections were between 26 and 40 mm in diameter. Some contained a linear arrangement of yellow-brown operculated eggs. The worms were surrounded by mucus that contained many red blood cells and a few neutrophils. Some parasites were observed in the lamina propria of the mucosae. Smaller worms ranging in size from 15 to 24 mm (hypothesized to be larvae) were noted in the deeper layers of the mucosa, within glandular lumens, and between the basement membrane and the epithelial cells of the glands. Regions of cellular necrosis and regeneration surrounded the worms. Eggs were noted in the pyloric mucus and in the lumens of the pyloric glands.

TREATMENT: When an infected cat was treated with levamisole (2 doses: 7.5 mg/kg at 2-week intervals, the first dose split 12 hours apart and the second dose given singly), eggs of Aonchothecaputorii disappeared from the feces (Greve and Kung, 1983).

Curtsinger etal. (1993) administered ivermectin (300mg/kg BW) per os one week following surgery and again two weeks later.

EPIZOOTIOLOGY: Infected cats may serve as carriers. The exact role of wild animals in the epizootiology of gastric capillariasis has not been studied.

HAZARDS TO OTHER ANIMALS: Aonchothecaputorii has been recorded from the American black bear, European hedgehog, racoon, swine, bobcat, and a variety of mustelids. Such a broad host range is typical for many capillarid species. Cross transmission is possible from host to host (Collins, 1973, Greve and Kung, 1983).

HAZARDS TO HUMANS: There have been no reports of cross transmission of Aonchothecaputorii to humans.

CONTROL/PREVENTION: Infection results from ingestion of soil contaminated by feces containing infective eggs. These feces could come from a variety of definitive hosts. Cats should not be allowed to roam freely.

LITERATURE CITED

Butterworth EW, Beverley-Burton M. 1980. The taxonomy of Capillariaspp (Nematoda: Trichuridea) in carnivorous mammals from Ontario, Canada. Sys Parasitol 1:211-236.

Cameron & Parnell, 1933

Campbell BG. 1991. Trichuris and other trichinelloid nematodes of dogs and cats in the United States. Comp Cont Ed Pract Vet 13:769-779, 801.

Curtsinger DK, Carpenter JL, and Turner JL. 1993. Gastritis caused by Aonchothecaputorii in a domestic cat. J Am Vet Med Assoc 203:1153-1154.

Collins GH. 1973. A limited survey of gastro-intestinal helminths of dogs and cats. NZ Vet J 21:175-176.

Collins GH and Charleston WAG. 1972. Ollulanustricuspis and Capillariaputorii in New Zealand cats. NZ Vet J 20:82.

Greve JH and Kung FY. 1983. Capillariaputorii in domestic cats in Iowa. J Am Vet Med Assoc 182:511-513.

López-Neyra CR. 1947. Los capillariinae. Memorias de la R. Academia de Ciencias exactas, físicas y naturales de Madrid 12:248 pp.

Rudolphi KA. 1819. Entozoorum synopsis cui accedunt mantissa duplex et indices locupletissimi. Berlin:813 pp.

Travassos, 1915

Wagner O. 1936. Beitrage zu einer Revision der Nematoden-Gattungen Capillaria, Hepaticola, und Eucoleus. Senckenbergiana 18(5,6):245-269.

FIGURES

Figure 4-59. Aonchothecapurtorii. Two views of the same egg of this worm. The top view shows the surface of the egg with its deep striations. The bottom view shows how the egghell appears to have a rough surface at midsection (Illustration courtesy of Dr. Barry Campbell).

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