Loiasis, the African eye worm
Loiasis, commonly known as the African eye worm is caused by the parasitic worm loa loa. Humans get infected through repeated bites of deerflies of the genus Chrysops. The flies are also known as mango flies or mangrove flies. The flies that infect humans breed in rain forests in West and Central Africa. Infection with the parasite can also manifest with repeated episodes of itchy swellings, referred to as Calabar swellings. Currently, there are more than 29 million people who are at a risk of getting infected with loaisis in Central and West Africa.
Case study
In a similar case, a 36-year-old anthropologist who had recently visited Central Africa republic as a part of her work presented to the outpatient clinic with a moving wormlike structure in her left eye. Laboratory studies showed that she had an absolute eosinophil count of 1.75 per cubic millimeter, reference range 0.01 to 0,59. A fresh blood smear was also examined via a microscope which showed fast-moving worms present at a count of 3400 per millilitre. Gamma-stained blood films further confirmed the presence of microfilaria with the presence of colourless sheaths, leading to the diagnosis of Loa Loa.
Diagnosis and treatment
Doctors diagnosed the patient with loaisis. The worms are known to migrate through subcutaneous tissues and can cause inflammatory swelling, also known as Calabar swelling. The patient was treated with a 20-day course of diethyl carbamazine. The dosage was started at 50 mg daily and increased to 300 mg daily. The patient was also prescribed prednisolone at a starting dose of 20 mg which was tapered over the course of 20 days. There were no signs of complications from treatment.
At 6-month follow-up the patient’s eosinophil count returned to a normal range with no signs of relapse.
Source: NEJM
