Loiasis or African eye worm is a disease cause by infestation of the parasitic round worm, loa loa. The worm can migrate under the skin, and sometimes it can cross the conjunctiva of the eye making it visible. Hence its name, the African eye worm. The movement of the worm when migrating between the eyes across the bridge of the nose can be painful. The worm can also travel to the brain causing encephalitis.
During the day, the worm is often observed floating in the blood and in the lymphatic fluid, and at night it is often observed in the lungs. Symptoms of loiasis may not appear in few months to few years from the day of infection. African eye worm infestation is common in the Congo River region, Ethiopia, and Sudan.
Causes and transmission of loiasis
Loiasis is cause by the infestation of the parasitic thread-like nematode or round worm called loa loa. People contract loiasis through the bite of a deer fly or mango fly carrying the larvae of the worm from biting an infected human being. The microfilaria stays under the skin until it fully matures into an adult worm. Male and female African eye worm can mate inside the host's body and multiply; the human body is the only known reservoir of the loa loa.
Symptoms and diagnosis of loiasis
Loiasis is hard to diagnose because it does not present in known symptoms. The quickest way to identify the infection is when the worm is visible when travelling under the conjunctiva where it is visible for observation for few minutes. The worm infestation can also cause red itchy swelling on the skin called Calabar swellings.
The diagnosis involves taking a blood sample from the suspected victim and examining it under a microscope. The microfilaria should be visible under the watchful eye of a train health care professional. The blood may also be filtered through a nucleopore membrane or processed through a centrifuge to help in exposing the microfilaria.
Treatment of loiasis
The African eye worm disease is usually cured by killing the worms with diethylcarbamazine taken three times daily for 12 days. Six milligrams of diethylcarbamazine per kilogram of the victim's body weight is recommended: the dosage is the same in adults and children. However, the drug is effective in killing the microfilaria but only partially effective against adult worms. Chemotherapy and surgical removal of adult worms can also be done to cure the infestation.
Prevention of loiasis
To prevent loa loa infestation, people are advised to avoid the insect vector at all times. When visiting places with known cases of loiasis, it is best to wear protective clothing that covers majority of the body. Insect repellent is also helpful when applied in right amount, and follow up application is needed in regular intervals. The use of bed net is also advised to avoid insect bite while sleeping. The use of diethylcarbamazine or ivermectin as prophylaxis is also a probable option against loiasis.
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