Capillariosis

Abstract

Capillaria species are members of the superfamily Trichinelloidae. These worms have a filamentous thin anterior end and a slightly thicker oesophagus which is surrounded by glandular cells or stichocytes. This oesophageal pattern is called stichosomal oesophagus. Capillaria species are parasites which are found in many vertebrate animals. More than two hundred species have been reported in several vertebrate species, including fish, amphibians, reptiles, birds, and mammals (Cross 1992; Chitwood et al. 1968), but only three species infect humans. These are Capillaria hepatica , C. aerophila and C. philippinensis (McCarthy and Moore 2000). Of these intestinal capillariosis, a fish-borne parasitic zoonosis caused by C. philippinensis , is the most important. Humans acquire the parasite, C. philippinensis, by eating uncooked or raw freshwater fish (Cross and Basaca-Sevilla 1991). The disease is endemic mainly in Philippines and Thailand where there are many reported fatalities.Although C . hepatica is found in rodents worldwide, only a few cases of hepatic capillariosis have been reported in humans from Europe, Asia, Africa, North and South America. The infection is acquired by the ingestion of embryonated eggs from the soil. Female worms deposit eggs in the liver tissue and granulomas develop around the egg. The eggs are released after the rodent is eaten and the liver digested. Eggs pass in the faeces and are deposited in the soil where they embryonate. Avoidance of contaminated soil would prevent human infection and destruction of rodents would control animal infections.Only 12 cases of human infection caused by Capillaria aerophila have been reported, the majority from Russia. The parasite is found within tissue of the respiratory passages of canines and felines worldwide.Anatrichosoma cutaneum (Nematoda, Trichosomoididae), also included in this chapter, is primarily a subcutaneous parasite of monkeys, but there are two reports of cutaneous infections in humans resulting in serpiginous lesions in the skin of the soles, palms, and nasal passages. In addition there is a further suspected case isolated from a breast nodule and a possible case of mucosal lesions in the mouth reported. Whole monkey colonies can be infected with this parasite and control is difficult.