2013, Number 4
Dermatología Cosmética, Médica y Quirúrgica 2013; 11 (4)
Ríos YJM, Ríos CM, Yuil RE, Mercadillo PP
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ABSTRACTCaused by the filarial nematode Onchocerca volvulus, onchocerciasis is a parasitic disease affecting some 37 million people worldwide, especially in Sub-Saharan Africa and to a lesser extent, Latin America. The infection begins with the bite of Simulium spp. insects, which inoculate third-stage nematode larvae that settle in the skin and subcutaneous tissues of the host, where they evolve into adult male and female parasites and are ultimately encapsulated in a fibrous reaction known as onchocercoma. The female goes on producing thousands of microfilariae on a daily basis and these larvae migrate through the skin until they are extracted in the bite of another Simulium spp., which thus acts as an intermediary host and vector. While onchocerciasis is characterized by an important skin involvement, the severe ocular disease can lead to blindness. Clinical manifestations are caused by the host immune response against the nematode and its contents, the endosymbiont Wolbachia sp. This response is dependent upon both the innate and adaptive immune systems, resulting in a mixed Th1/Th2 reaction. So far, the strategy used to control the disease has been the massive distribution of ivermectin in high-risk populations; however, this has proven to be ineffective. Although other approaches have been tried, including an anti-Wolbachia treatment, it is imperative to develop more effective drugs to eradicate this disease.