Loiasis

Loiasis, also known as Loa loa infection or African eye worm, is a tropical parasitic disease caused by the filarial worm Loa loa. The infection is spread through the bite of deer flies (Chrysops species), which are found in the rainforests and swamp forests of West and Central Africa. When an infected fly bites a person, it deposits tiny worm larvae into the skin. Over months to years, these larvae grow into adult worms that can migrate through the tissues under the skin and sometimes across the surface of the eye, which is how the disease got its common name "eye worm." The most recognizable symptoms include Calabar swellings — temporary, painless or slightly painful swellings that appear on the arms, legs, or other body parts and last a few days before disappearing. Patients may also notice an adult worm moving across the white part of the eye, which can be alarming but is usually not dangerous to vision. Other symptoms include itching, joint pain, fatigue, and sometimes swelling of the limbs. Many infected people have no symptoms at all but carry high levels of a type of white blood cell called eosinophils in their blood. Treatment typically involves antiparasitic medications, with diethylcarbamazine (DEC) being the primary drug used. However, treatment must be carefully managed because in patients with high numbers of microfilariae (baby worms) in the blood, rapid killing of the parasites can trigger a severe and potentially life-threatening brain inflammation called encephalopathy. For this reason, doctors often check the level of microfilariae in the blood before starting treatment. In some cases, a procedure called apheresis may be used to reduce the worm burden before drug treatment begins. Albendazole may also be used as a slower-acting alternative.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Bring these to your next appointment

• Q1.What is my microfilariae level, and does it affect which treatment is safe for me?,What are the risks of treatment, and how will you monitor me for complications like encephalopathy?,How long will treatment take, and will I need multiple rounds of medication?,Should my family members or travel companions also be tested?,What can I do to prevent reinfection if I return to or live in an endemic area?,Are there any medications I should avoid because of my loiasis infection, such as ivermectin?,Will I need long-term follow-up after treatment to make sure the infection is fully cleared?

Common questions about Loiasis

Related conditions

Other rare diseases commonly researched alongside Loiasis.

• Dirofilariasis→