Loa loa infection without microfilaraemia

A diagnosis of loasis without microfilaraemia was made in the United States of America 8 to 11 years after the patient's exposure in an endemic area of Central Africa. Surgical removal of 5 parasites from the patient's eyelids during a span of 7 years revealed that all were mature, unfertilized females. A unisexual infection reported in this case appears to be another cause of amicrofilaraemia in loasis. The erratic behaviour of Loa loa parasites, combined with amicrofilaraemia for years after the patient's exposure to infection may cause a very difficult diagnostic problem.