General Discussion

Acanthocheilonemiasis is a rare tropical infectious disease caused by a parasite known as Acanthocheilonema perstans, which belongs to a group of parasitic diseases known as filarial diseases (nematode). This parasite is found, for the most part, in Africa. Symptoms of infection may include red, itchy skin (pruritis), abdominal and chest pain, muscular pain (myalgia), and areas of localized swelling (edema). In addition, the liver and spleen may become abnormally enlarged (hepatosplenomegaly). Laboratory testing may also reveal abnormally elevated levels of certain specialized white blood cells (eosinophilia). The parasite is transmitted through the bite of small flies (A. coliroides).

Signs & Symptoms

Initially people with Acanthocheilonemiasis may have no symptoms. Symptoms occur more frequently in people who visit the areas where this parasite is common (endemic), than in people who are native to that area. One common laboratory finding, in people who have recently returned from infected areas, is abnormally high levels of specialized white blood cells (eosinophilia). Generally there are no symptoms associated with the laboratory finding.

When symptoms appear they may include itchy skin (pruritis), abdominal pain, chest pain, muscle pains (myalgias), and/or areas of swelling under the skin (subcutaneous). Examination by a physician may reveal an abnormally enlarged liver and spleen (hepatosplenomegaly), and abnormally high levels of granular white blood cells (eosinophilia). The adult worm (nematode) may lodge in the tissues of the abdomen and chest causing inflammation and immune reactions. This may result in inflammation of the lining of the lungs (pleuritis) and/or the membranes that surround the heart (pericarditis).

The early or prelarval form (microfilariae) of Acanthocheilonema perstans can be isolated from the blood from patients with Acanthocheilonemiasis. Generally this disease is diagnosed by the examination under a microscope of a thick blood smear taken from the patient.

Causes

Acanthocheilonemiasis is a rare infectious disease caused by long “thread-like” worms, Acanthocheilonema perstans, also known as Dipetalonema perstans. The disease is transmitted by a small black insect (midge), called A. Culicoides.

Affected Populations

Acanthocheilonema perstans, the parasite that causes Acanthocheilonemiasis is common in central Africa and in some areas of South America. This disorder affects males and females in equal numbers.

Related Disorders

Symptoms of the following disorders can be similar to those of Acanthocheilonemiasis. Comparisons may be useful for a differential diagnosis:

Filariasis is a group of rare infectious diseases caused by parasitic worms. These disorders are characterized by abnormal changes with the lymph glands (lymphadenopathy) and chronic obstruction of the flow of lymphatic fluid. This may result in the extreme swelling of the legs and/or genitalia (elephantiasis). This parasite enters the body by a mosquito bite. (For more information on this disorder, choose “Filariasis” as your search term in the Rare Disease Database.)

Other tropical diseases can cause similar symptoms to Acanthocheilonemiais. For more information choose “Tropical” as your search term in the Rare Disease Database.