The Onchocercidae are a family of nematodes in the superfamily Filarioidea. This family includes some of the most devastating human parasitic diseases, such as lymphatic filariasis, onchocerciasis, loiasis, and other filariases. The taxonomy of nematodes in the order Spirurida is still in a state of flux, and the family Onchocercidae contains around 70–80 genera. The following genera are included in the family Onchocercidae in the Wikispecies project and the Entrez Taxonomy Browser. The latter is the taxonomic system used in the NCBI family of databases, including PubMed.