GENERAL CHARACTERISTICS
Capillaria philippinensis was first recognized as a human parasite in the late 1960s and now has a well-known wide distribution. This parasite is prevalent in the northern Philippines, hence the name C. philippinensis, and has also been found in Thailand, Japan, Taiwan, Iran, and Egypt. The parasite reproduces in the gut, resulting in autoinfection and hyperinfection very similar to that observed in S. stercoralis.
EPIDEMIOLOGY
Human infection is thought to occur from the ingestion of uncooked fish harboring infective larvae. In the Philippines, where the organism is prevalent, the people ingest a large spectrum of raw seafood, including fish, shrimp, crabs, and snails. In addition, defecation in the fields or water sources where snails, shrimp, and crabs are collected is common. The life cycle of the parasite is currently not fully understood.
PATHOGENESIS AND SPECTRUM OF DISEASE
Symptoms vary with the level of worm burden. The larvae are ingested and reside in the small intestine where they burrow into the mucosa. Because of the mechanical insertion into the intestinal wall, patients lose weight rapidly as a result of malabsorption and fluid loss. Long term infections lasting weeks to months may result in death attributable to a severe loss of electrolytes, particularly potassium (hypokalemia), and associated organ failure. See Table 1 for a summarized detail of associated diseases.
Table1. Pathogenesis and Spectrum of Associated Diseases
Table1. Pathogenesis and Spectrum of Disease—cont’d
LABORATORY DIAGNOSIS
Diagnosis is typically from the identification of eggs, adult worms, or larvae in stool specimens. The eggs resemble those produced by T. trichiura. They are somewhat smaller with a thick, striated shell and less prominent polar plugs. Female worms produce the characteristic thick-shelled eggs as well as thin-shelled and free larvae.
THERAPY
Anthelmintic agents including albendazole and mebendazole are recommended.
PREVENTION
Adequate preparation and cooking of seafood, including fish, snails, crabs, and shrimp in endemic areas, are encouraged.
