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Anatrichosoma species

(Figure 4-63)

This genus of rarely encountered, capillarid-like worms was first discovered in the skin and nasal mucosa of monkeys in Asia and Africa and was named Trichosomacutaneum by Swift, Boots, and Miller (1922). The genus Anatrichosoma was created in 1954 for a second species, Anatrichosomacynomolgi, also from monkeys (Smith and Chitwood, 1956; Chitwood and Smith, 1958). In the genus Anatrichosoma, there are now seven recognized species that have been reported from a wide variety of tissue sites in primates, rodents, shrews, and marsupials. Anatrichosomacutaneum and Anatrichosomacynamolgi have been detected in the skin and nasal mucosa of Asian monkeys (Allen, 1960; Orihel, 1970) (Fig. 4-63). Anatrichosoma. rhina and Anatrichosomanacepobi have been reported from the nasal mucosa of Indian monkeys (Conrad & Wong, 1973). Anatrichosomagerbilis was described from specimens collected from the stomach mucosa of a North African gerbil (Bernard, 1964). Anatrichosomaocularis was described from the eye of the common Thai tree shrew (File, 1974). Anatrichosomahaycocki has been described from the dasyurid marsupials, Antechinus swainsonii and Antechinus stuartii, where it lives in the paracloacal glands (Spratt, 1982). Anatrichosomabuccaliswas described from the buccal mucosa of the common opossums, Didelphismarsupialis, that were collected in Louisiana, Costa Rica, and Colombia (Pence and Little, 1972).

The only report of anatrichosomiasis from the cat occurred in South Africa (Lange et al., 1980). The affected cat appeared listless and depressed at the time of clinical presentation. The cat was disinclined to move due to complete or partial sloughing of the epidermis of the footpads of all four feet. The lesions resembled burn wounds with necrosis of the epidermis and exudation which caused caking of the hair on the feet and between the toes. With sloughing of the epidermis of a particular footpad, the underlying tissue appeared soft and red. The dorsal surface of both carpal joints had pressure sores characterized by alopecia, scab formation and thickened skin. The cat was euthanatized due to a diagnosis of chronic interstitial nephritis. At post mortem examination, all five pads of the left front paw had no epidermis. The center pad of the right front paw demonstrated almost complete detachment of the epithelium. The detached part was dry, discolored and hard. Both hind feet showed similar lesions of the center pads and the lateral toe pads. A single intact female worm and fragments of three others were recovered from the cat's footpads. The total length of the female worm was slightly over four centimeters. The stichosome esophagus makes up about 10% of the total body length, and the vulva is just behind the termination of the esophagus. The uterus was filled with bi-operculate brown eggs, each of which was larvated. The eggs were 63-72 m by 35-44 m.

There have been no successful experimental infections of any host with any species of Anatrichosoma. In the case of Anatrichosomabuccalis of the common opossum of North and South America, the adult female nematodes make extensive tunnels through the superficial layers of the hard palate, gum, and tongue (Pence and Little, 1972, Little and Orihel, 1972). Male nematodes are usually found in the deeper layers of the dermis and, more rarely, in the outer epidermal layers associated with the females. Males reside in tunnels that are not so well defined. The males are about the same length as the females, but are much thinner, and during copulation, the posterior end of the male worms is inserted into the uterus of the female. When they are not copulating, the males leave the females and migrate from the mucosal epithelium to the deeper tissues. The females to make extensive tunnels through the superficial layers of the stratified squamous epithelium and leave a trail of embryonated eggs as they wander through the tissue.

Other than the cat, species besides primates, marsupials, and shrews that have been host to rare infections include dogs in Alabama and Arizona, USA, and human beings in Japan, Vietnam, and Malaysia. In the first report of Anatrichosoma infection in a dog, the initial diagnosis was made by observing typical eggs on fecal flotation (Hendrix etal., 1987); the dog had presumably licked the skin lesion and the eggs were swallowed and passed out in the feces. In the second canine infection, the diagnosis of infection in the dog in Arizona was made when the eggs were recognized to be present in the hundreds in the washed detritus from both ears (Hendrix et al, 1990). In the case in the human being in Japan, single lesions, red zigzag tracks, appeared on the left middle finger and on the right ankle of a businessman (Morishita and Tani, 1960). The tracks grew about 5 to 10 mm each day. A single female worm was removed from the end of each tract , the worms were about 25 mm long. In the Vietnamese case Lê-van-hoa, et al., (1963) lesions containing worms or eggs were observed betweent he fingers of the hands, on the left foot, and scrotum. In the Malaysian case, the discovery of Anatrichosoma eggs was an incidental finding in an asymptomatic person who face was scraped as part of a survey on the prevalence of Demodex within the aboriginal Malaysian population (Marwi et al., 1990).


Allen AM. 1960. Occurrence of the nematode, Anatrichosomacutaneum, in the nasal mucosae of Macacamulatto monkeys. AJVR 21:389-392.

Bernard J. 1964. Trichosomoides gerbilis n. sp. parasite stomacal d’un gerbille d’Afrique du Nord. Arch Inst Past Tunis 41:33-38.

Chitwood MB, Smith WN. 1958. A redescription of Anatrichosomacynamolgi Smith and Chitwood, 1954. Proc Helm Soc Wash 25:112-117.

Conrad HD, Wong MM. 1973. Studies on Anatrichosoma (Nematoda: Trichinellida) with descriptions of Anatrichosomarhina sp. n. and Anatrichosomanacepobi sp. n. from the nasal mucosa of Macacamulatta. J Helminthol 47:289-302.

File SK. 1974. Anatrichosomaocularis sp. n. (Nematoda: Trichosomoididae form the eye of the common tree shrew, Tupaiaglis. J Parasitol 60:985-988.

Hendrix CM, Blagburn BL, Boosinger TR, Logan RT, and Lindsay DJ. 1987. Anatrichosoma sp infection in a dog. J Am Vet Med Assoc 191:984-985.

Hendrix CM, Greve JH, Jeffers MD, and Glock RD. 1990. Observation of Anatrichosoma-like eggs from otic irrigations of a dog. Canine Prac 15:34-36.

Lange AL, Verster A, Van Anstel SR, and De La Rey R. 1980. Anatrichosoma sp. infestation in the footpads of a cat. J S Afr Vet Assoc 51:227-229.

Lê-van-hoa, Duong-hong-mo, and Nguyên-luu-viên. 1963. Premier cas de Capillariose cutanêe humaine. Bull Soc Path Exot 56:121-126.

Little MD and Orihel TC. 1972. The mating behavior of Anatrichosoma (Nematoda: Trichuroidea). J Parasitol 58:1019-1020.

Marwi MA, Omar B, Mahammod CG, Jeffery J. 1990. Anatrichosoma sp. egg and Demodexfolliculorum in facial skin scrapings of Orang Aslis. Trop Biomed 7:193-194.

Morishita K and Tani T. 1960. A case of Capillaria infection causing creeping eruption in man. J Parasitol 46:79-83.

Orihel TC. 1970. Anatrichosomiasis in African monkeys. J Parasitol 56:982-985.

Pence DB and Little MD. 1972. Anatrichosomabuccalis sp. n. (Nematoda: Trichosomoididae) from the buccal mucosa of the common opossum, Didelphismarsupialis L. J Parasitol 58:767-773.

Spratt DM. 1982. Anatrichosomahaycocki sp. n. (Nematoda: Trichuridae) from the paracloacal glands of Antechinus spp., with notes on Skrjabinocapillariaskaarbilovitsch. Ann Parasitol Hum Caomp 57:63-71.

Smith WN, Chitwood MB. 1954. Anatrichosomacynomolgi, a new trichurid nematode from monkeys. J Parasitol 40 (suppl):12.

Swift HF, Boots RH, Miller CP. 1922. A cutaneous nematode infection in monkeys. J Exp Med 35:599-620.


Figure 4-63. Anatrichosomacynomolgi. This is a section through the skin of a monkey showing various sections through the worm that is embedded in the epithelium.