Loiasis is an infection with a parasitic worm. You get it from the bite of infected deer flies that live in parts of Africa. The most common symptom is painless swelling that comes and goes. Many people don’t have symptoms.
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Loiasis is an infection with the parasitic worm Loa loa. You get it from the bite of deerflies that live in West and Central Africa. It can cause joint swelling that comes and goes. Many people don’t have any symptoms.
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Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy
If you take a short trip to Africa, your chances of getting loiasis are small. You usually need to be bitten by infected flies many times over several months to get infected.
Loiasis (low-eye-AYE-sis) is also sometimes called African eye worm. It’s a type of filariasis.
Many people with loiasis don’t have symptoms. The most common symptom is itchy, swollen areas on your body (Calabar swellings). These can come and go as the worms move around in your body. They can happen anywhere, but they’re most common near your joints, like knees and elbows.
You may also have:
You might see worms moving under your skin or across your eye.
Loa loa roundworms, a type of parasitic worm, causes loiasis. You can get it when an infected fly bites you. Deer flies and mangrove flies spread Loa loa worms. They’re only found in Africa.
Once the worms are in your body, they grow into adults over several months. As they grow, they can move to your body’s tissues and organs, causing swelling.
Healthcare providers use blood tests to diagnose loiasis. A provider might order them if you have symptoms and have lived in or traveled to Africa. A lab will look for the worms in a sample of your blood. Your provider may also notice worms moving under your skin or across your eye. Let your provider know if you’ve traveled to or lived in Africa.
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Healthcare providers use antiparasitic medications to treat loiasis. A provider may surgically remove worms that are visible on your eye. You may need to see an infectious disease doctor who specializes in tropical diseases for treatment.
Before treatment, your provider may order a test to see how severe the infection is and whether you’re infected with other parasitic worms. If you have severe loiasis or additional infections, you may need more medications or a blood-filtering procedure (apheresis).
Medications you might need include:
See a healthcare provider if you:
Your provider might recommend taking preventive medicines to reduce your risk of infection if you’re planning a trip. These can take some time to get, so it’s best to talk to a provider as soon as possible.
Most cases of loiasis aren’t serious. You’ll need to take medication for about three weeks. Some people need to take more than one round of treatment. You might also have visible worms removed with surgery.
You can reduce your risk of infection when traveling to areas where loiasis spreads by:
Loiasis is uncommon in the U.S. But you might get it if you travel to certain parts of the world. If you have symptoms and have traveled to places where Loa loa spreads, talk to your healthcare provider. They may recommend seeing a specialist for diagnosis and treatment.
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