Onchocerca volvulus in a nutshell:
Onchocerciasis is an infection caused by parasitic worm Onchocerca volvulus (Nematoda: filarial worm) spread by black fly. It is also called river blindness because the fly can cause blindness. The world health organization estimates that at least 25 million people are infected and 23 million people live in the areas that put them at risk of being infected. The most likely areas to be infected are Africa in Yemen and in the Middle East. Those most at risk are people who live in areas where the parasite is spread followed by adventure, travelers, missionaries and Peace Corps volunteers. The best prevention is avoiding being bitten by infected black flies by using insecticides. Unfortunately, there is no vaccine
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The larvae become adult in around 3 months to year. Nodules formed due to interaction between parasite and its human host.
-Some people don not experience symptoms while infected with O.volvulus. The larvae can migrate through the human body through the human body without any response from the immune system.
-Many people experience the symptoms which include itchy skin rashes, nodules under the skin and vision changes .Non- painful swelling of lymph glands.
- These symptoms caused by the response to dead larvae. In addition to itching it can cause long-term damage to the skin.
-They can cause changes in color of the skin that result in "leopard skin" appearance.
-Thinning of the skin with loss of elastic tissue "cigarette-paper" appearance.
-Permanent clouding of the cornea resulting in blindness and inflammation of the optic nerve.
Diagnosis: Diagnosis of Onchorerciasis can be difficult. There are multiple methods that the diagnosis can be made. 1) The most common method is taking a tissue biopsy of the skin to identify larvae and put and put it in a physiologic solutions e.g (normal saline) 2) If there are nodules on the skin. The nodule can be surgically removed and examined for adult