What Is Loiasis?

Loiasis is a parasitic infection endemic to rain forest and swamp regions in western Africa. It is caused by a nematode worm known locally as “loa loa,” and is sometimes referred to as loa loa filariasis. Patients with this condition develop a subcutaneous infection that can also spread to the eyes and the mucous membranes. As the worms travel through the body, they cause inflammation and irritation. This condition can appear with comorbidities, making it challenging to treat effectively.

The infection starts with a bite from a fly. The worms can incubate for months and even years before they start to travel through the skin, causing distinctive bumps known as Calabar swellings. Patients usually report itching, irritation, and redness. The worms can be visible in the eyes and mucous membranes, traveling just below the surface. Muscles and joints may swell, causing aches, pains, and limited mobility. Patients may also experience pain in their eyes because of the movement of the worms.

Loa loa worms can live inside a patient with loiasis for years. The patient may experience discomfort, but the infection will not be fatal. Treatment involves chemotherapy to kill the worms. In some cases, a doctor may recommend surgery to remove worms and facilitate treatment. Once the worms are dead, the patient should experience an improvement and feel more comfortable. Lingering skin irritation is treatable with soothing creams to keep inflammation down while the body recovers.

There are some prevention techniques available to address loiasis. Using insect nets, repellent, and appropriate garments can reduce the risk of a bite from a fly carrying the parasite. In addition, it is possible to take prophylactic drugs to prevent infection in the event of a bite. Travelers can access these medications along with other prophylactic treatments that a doctor may recommend, such as antimalarial drugs. Costs for loiasis prevention vary, depending on the measures a patient takes, but are usually lower than the costs for treatment.

Patients with a history of travel in regions where parasites like the loa loa worm are present should make sure this is noted in their chart. The lengthy incubation of many infections means that patients and doctors may not immediately connect symptoms like itchy red bumps with a condition like loiasis, delaying diagnosis and appropriate treatment. Recording any travel history will allow a doctor to consider the possibility of a long-dormant parasitic infection when a patient arrives with a complaint of skin lesions or irritation of the mucous membranes.