Ascaris: The Neglected Parasite

Book excerpt: The structural simplicity of nematode nervous systems has provided a useful resource for studies on basic neurobiology. Two species have underpinned basic neuroscience research in phylum Nematoda, the free-living nematode Caenorhabditis elegans and the pig parasitic nematode Ascaris suum due to their genetic tractability and large size, respectively. The fact that most of the chemotherapeutic targets for the treatment of roundworm parasite infections of animals and man associate with neuromuscular function means that nematode neurobiology research resonates beyond discovery biology and informs parasite control. These diverse drivers for the interrogation of nematode neurobiology have exposed a unique approach to the regulation of complex behavioral traits, encompassing structural simplicity with profound chemical complexity. The latter embraces extreme diversity in both the ligand-gated ion channel subunit complements for classical neurotransmitters and in the neuropeptide ligands that signal mostly via G-protein coupled receptors, offering compelling opportunities for parasite control-target discovery and validation.