Causes of Onchocerciasis
It is caused by a parasitic worm, Onchocerca volvulus, which causes river blindness. The infection is transmitted through the bites of infected black flies (genus Simulium). In Africa, Latin America, and Yemen, these flies breed in fast-flowing rivers and streams.
Symptoms of Onchocerciasis
Onchocerciasis may cause the following symptoms:
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The skin manifests as severe itching, skin lesions, and depigmentation.
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Progressive vision loss, particularly peripheral vision loss (river blindness).
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In the skin, nodules are firm, painless swellings caused by adult worms.
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Some patients experience fever, headaches, and muscle pain as systemic symptoms.
Diagnosis of Onchocerciasis
Clinical evaluation and specific tests are required for diagnosis:
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Microfilariae (larval forms of the parasite) are detected under a microscope through a skin biopsy.
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Detection of antibodies against Onchocerca volvulus by serological tests.
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Skin samples can be tested for parasite DNA using PCR (Polymerase Chain Reaction).
Treatment of Onchocerciasis
The goal of treatment is to eliminate the parasite and manage symptoms:
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The oral medication ivermectin kills microfilariae and reduces symptoms. It is used in endemic regions for mass drug administration programs.
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Subcutaneous nodules can be removed surgically if they become bothersome or infected.
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Treatment of secondary bacterial infections of the skin or eyes with antibiotics.
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Medications that relieve itching and discomfort.
Prevention of Onchocerciasis
Vector control and community-based interventions are the main preventive measures:
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Larviciding and environmental modifications are used to control vectors.
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Ivermectin is administered regularly to at-risk populations to reduce parasite reservoirs and transmission.
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Awareness programs about the disease, its transmission, and prevention.
Onchocerciasis is discussed in this overview, including its causes, symptoms, diagnosis, treatment options, and prevention.
