Introduction: There are 12 protozoan genera that provoke zoonotic disease in humans and animals. We discuss the most common ones with a highlight on Babesia spp and Entamoeba histolytica, also mentioning Toxoplasma gondii, Trypanosoma cruzi, and Leishmania spp.
Areas covered: The complex life cycle of pathogenic protozoans is deeply understood but this did not contribute to the discovery of new drugs. The clinical armamentarium is poor and includes antiinfectives originally proposed as antibacterial (azithromycin, clindamycin, paromomycin, sulfadrugs), antifungals (amphotericin B), or they are outdated compounds with poor efficacy and many side effects (nitroazoles, antimonials, etc.). Few patents and innovative ideas are available.
Expert opinion: Protozoan diseases are not restricted to tropical countries and are difficult or impossible to treat with currently available drugs, which are limited and restricted to a low number of clinical classes. The antiprotozoal drug targets are also limited, and this had deleterious effects on translational studies for designing efficient antiprotozoal drugs. There is a stringent need for innovative approaches to tackle these problems.
Keywords: Babesia; Entamoeba histolytica, zoonosis; Protozoa; antiprotozoal drug; drug repurposing.