A 37-year-old woman’s right eye was intensely red and painful when she arrived at a hospital in the UK. During the examination, doctors discovered the cause: a long, thin worm was moving beneath the conjunctiva, the membrane covering the white part of the eye.
The patient was French, of Congolese origin, and had been living in the UK for six months. She was also HIV-positive. Her vision, however, remained normal, and she had no inflammation inside the eye.
The doctors made a small incision of just 2 millimeters in the conjunctiva and managed to remove the live worm intact with forceps. It was later identified as an adult female of Loa loa, a parasite known as the “African eye worm”.
But removing the worm they could see did not mean the infection was over. Blood tests performed during the day found Loa loa microfilariae: microscopic forms of the parasite circulating in her body. The count was 55 microfilariae per 20 milliliters of blood.
The patient was initially given ivermectin and, a month later, 21 days of diethylcarbamazine to eliminate the remaining parasites. The doctors used corticosteroids during treatment to reduce the risk of an inflammatory reaction caused by the death of the microfilariae.
More than a year later, the woman had not experienced any further symptoms, and tests no longer detected microfilariae in her blood. The case was published in BMJ Case Reports in 2011, and the authors emphasized that the infection should be considered when someone from an area where the parasite is endemic presents with unusual eye symptoms.