Barber's Pole Worms in Humans

The barber pole worm, Angiostrongylus cantonensis, is a parasitic nematode--or roundworm--that can lead to serious infection, and even death in some cases, when it infects a human host. The adult female worm has a "barber pole" type spiral on her body, leading to the common name barber pole worm.

Hosts

• Barber pole worms are commonly found in the pulmonary arteries of rats, from which they get another name: rat lungworms. The mature adult worms are found only in rats.

  Snails and slugs are the primary intermediate host, and this is where the larvae develop until they are infective. Rats pass the immature larvae in their feces, and snails and slugs get infected by ingesting the rat feces. The larvae mature in the snails and slugs but will not become adult worms unless the snail or slug is eaten by a rat.

Transmission

• Humans might get barber pole worms from ingesting the larvae in raw or undercooked snails or from contaminated water or vegetables. After ingestion, the larvae travel through the blood to the central nervous system. Because humans are incidental hosts, the barber pole worm cannot reproduce within a human.

Symptoms

• The worms may incubate in their human host from one week to 47 days. Early symptoms of a barber pole worm infection include severe abdominal pain, nausea, vomiting and weakness. A fever might develop with severe headache and stiffness of the neck. Most cases will resolve themselves without treatment.

  In some cases, the barber pole worm will infect the eye of its human host. Vision will be impaired, there will be pain in the eye and retinal edema. Sometimes the worms can be removed surgically from the eye.

Angiostrongyliasis

• The barber pole worm causes angiostrongyliasis, which is the most common cause of Eosinophillic meningitis in Southeast Asia and the Pacific Basin. Eosinophillic meningitis can lead to death or permanent brain or nerve damage.

Diagnosis

• Diagnosis of angiostrongyliasis is difficult. It is usually based upon the patient presenting with Eosinophillic meningitis and having a history of travel to an infected area or of exposure to a snail host.

Treatment

• There is no specifically defined treatment for angiostrongylus, but most physicians use a combination of anti-parasitic medications--which might include albendazole, ivermectin, mebendazol or pyrantel--and steroids to limit inflammation as the worms die. Pain medication is often prescribed to ease the patient's discomfort from Eosinophillic meningitis.