Loiasis

Loiasis, or Loa Loa filariasis, is an eye disease caused by the Loa Loa worm. The Loa Loa worm is a parasitic nematode found in Central and West Africa. It travels through the subcutaneous tissue in a human host, and can be seen when crawling across the eye. For this reason it is commonly referred to as the “African Eye Worm” or “Eye Worm.”

Infection

Loa Loa worms are introduced to the human body by Mango or Deer flies, which carry the Loa Loa larvae and transfer them to a human through biting. Once introduced to the human host, the larvae travel across the body through the subcutaneous tissue while they grow and mate. Since the worms are under the skin’s surface, they are usually not noticeable until they cross the eye. Even then, the worms are constantly moving, so their presence in the eyes only lasts for a few minutes. The experience is typically painful when the worm travels across the eyes and the bridge of the nose.

Lifecycle

A Loa Loa worm’s lifecycle begins inside the human body when the worm is in its microfilaria stage. During this stage, they swim in the human bloodstream, waiting for a fly to bite so they can transfer to the fly’s body. Once the microfilariae infect the fly, they molt into the larvae stage and are transferred to a human in the next bite. The larvae then mature into adults and reproduce microfilariae, thus completing the lifecycle. Loa Loa worms can live up to 15 years, and can grow up to 2.5 inches with the females being substantially longer than the males.

Diagnosis

Loa Loa filariasis can be diagnosed through physical observation or a blood smear. Taken at the right time, the blood smear can identify Loa Loa microfilariae in the blood stream.

Symptoms

Symptoms of Loa Loa worm infection are minimal. The worm’s presence is only noticed when they travel across the eye, or stop for a moment at a specific point in the body. Once the worm is still, the body’s immune system reacts to the worm’s presence by inducing redness, swelling, pain, or itching. When the worm starts moving again, the symptoms disappear. The corpse of a deceased worm can also cause the immune system to react, which induces swelling.

Treatment and Prevention

Treatment of Loa Loa worms includes surgery, medication, and chemotherapy. A vaccine has yet to be discovered. The best methods of prevention include insecticides that have DEET, long pants, long-sleeved shirts, and mosquito nets in sleeping quarters. If you believe that you have been infected with loiasis, contact emergency services immediately.

WARNING: The following video shows the surgical removal of a loa loa worm and contains graphic imagery which may not be suitable for some viewers.