Today, ivermectin is being used to treat billions of livestock and pets around the world, helping to boost production of food and leather products, as well as keep billions of companion animals, particularly dogs and horses, healthy. Indicative of the impact, in Brazil, where some 80% of the bovine herd is infested, losses total about $2 billion annually 10). Ivermectin is also highly effective against ticks, for example, the ixodid tick Rhipicephalus (Boophilus) microplus, one of the most important cattle parasites in the tropics and subtropics, which causes enormous economic damage. Ivermectin is effective against a wide range of parasites, including gastrointestinal roundworms, lungworms, mites, lice and hornflies 9). Despite decades of searching around the world, the Japanese microorganism Streptomyces avermitilis remains the only source of avermectin ever found 8). Ivermectin was the world’s first endectocide (veterinary parasiticide), forerunner of a completely new class of antiparasitic agents, potently active against a wide range of internal and external nematodes and arthropods. When it first appeared in the late-1970s, ivermectin, a derivative of avermectin was a truly revolutionary drug. Pilot field trials in western Africa indicate that the mass drug administration of ivermectin against onchocerciasis and lymphatic filariasis can simultaneously reduce survival of Anopheles gambiae and local malaria transmission 7). Anopheles species shown to be susceptible to ivermectin at these concentrations include major vectors from Africa (Anopheles gambiae, Anopheles arabiensis), Southeast Asia (Anopheles campestris, Anopheles dirus, Anopheles minimus, Anopheles swandwongporni) and Latin America (Anopheles aquasalis, Anopheles darlingi). At these plasma concentrations, ivermectin can significantly reduce the survival of Anopheles mosquitoes that ingest treated blood. The recommended dose of ivermectin used to treat humans for filarial infection 6). The large-scale administration of oral ivermectin to people has become a cornerstone in the global eradication campaign against human onchocerciasis and lymphatic filariasis 5). Ivermectin has a high safety profile in humans and livestock 3) and is one of the most commonly-used anti-helminthic drug in the livestock industry to control intestinal nematodes 4). Ivermectin does not readily pass the mammal blood-brain barrier to the central nervous system where glutamate-gated chloride channels locate, hence the hosts are relatively resistant to the effects of this agent. As a result, neurons or muscle cells remain at either hyperpolarisation or depolarization state, thereby resulting in paralysis and death of the parasites. Distinct from the channel opening induced by endogenous glutamate transmitter, ivermectin-activated channels open very slowly but essentially irreversibly. Ivermectin binds to and activates the glutamate-gated chloride channels of nerve and muscle cells of a wide variety of nematode (parasitic worms) and arthropod species, causing uncontrolled influx of chloride ions into the cells and leading to paralysis and death of the organism 2). Ivermectin acts as an endectocide (i.e., kills both endoparasites and ectoparasites). Ivermectin is a lipophilic drug that belongs to the avermectin class (mostly avermectin H2B1a with some avermectin H2B1b) of macrocyclic lactone compounds 1). In the Western hemisphere, varieties of Simulium species bite humans and may transmit parasites. Some game animals, notably elands and buffalo, are possible reservoir hosts. In tropical Africa, Onchocerca parasites (Onchocerca volvulus) are transmitted primarily by Dipteran blackflies of the Simulium damnosum complex, members of the Simulium neavei group also being vectors. Ivermectin is an anti-parasite medication with activity against several parasitic nematodes (parasitic worms) and scabies and is the treatment of choice for onchocerciasis (also called “river blindness” because the blood-feeding flies that transmit the ultimately blinding disease inhabit lush, fertile land alongside the rivers in which they breed). Ivermectin has a broad spectrum of activity against several nematodes (Ascaris, Trichuris, Ancylostoma), cestodes (Taenia) and trematodes (Fasciola, Schistosoma). Ivermectin has particularly potent activity against onchocerciasis (river blindness) and lymphatic filariasis, which are important endemic diseases in Africa and South America.