Loiasis, commonly referred to as African eye worm, is caused by the parasitic worm Loa loa. It is transmitted to humans by repeated bites from Chrysops deer flies (also called mangrove or mango flies), the parasite-carrying flies that breed in West and Central African rainforests.

In Africa, determining if someone has a Loa loa infection has grown increasingly crucial. More than 29 million individuals may be at risk of contracting loiasis in affected West and Central African regions.


The majority of people who have loiasis don’t have any symptoms, although some of the following are possibilities:

  • Itching throughout your body
  • Joint or muscle pain
  • The worm travels over your eye’s conjunctiva, the eye surface lining, and inside your eyelids
  • Fatigue
  • Swollen, itchy, or painful spots on your body, particularly around joints such as your elbows or knees, are called Calabar swellings. After a few days, the swelling may go away only to reemerge weeks or days later.
  • Worms that may be seen crawling beneath your skin.


If you have loiasis symptoms and have been to or reside in affected regions of Africa, your physician may recommend a blood test. This test will detect the presence of Loa loa microfilariae in one’s blood. Your physician may also perform a physical exam to search for indications of loiasis, including swollen, itchy spots on your body.


Loiasis is treated with antiparasitic drugs like diethylcarbamazine (DEC) and ivermectin. On the other hand, individuals who have significant quantities of Loa loa microfilariae in their blood may have fatal responses to these drugs. Before administering ivermectin or DEC, the practitioner may prescribe a test to determine the number of microfilariae in one’s blood.

Furthermore, DEC and Ivermectin may not be safe when you have over 8,000 microfilariae for every milliliter of blood. Firstly, your doctor may advise you to take albendazole or undergo a blood-filtering process. Both blood filtration and the use of albendazole are effective in lowering the microfilariae count in the blood. If this is the case, then DEC or ivermectin could be your best option.

Because loiasis is uncommon in the United States, your doctor may refer you to a tropical medicine specialist to treat the illness. You should consult an expert doctor if you have a severe infection.

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