Frontiers in Parasitology Grand Challenge

Parasites are themost prevalent group of eukaryotic organisms on the planet. Humans harbor more than 300 species of helminths and 70 species of protozoans (Cox, 2002). Some of these parasites are rare or accidental passengers, but at least 90 parasites are relatively common inhabitants of the human body. If the other 65,000 species of known vertebrates house a similar number of different parasites, then we are talking about almost 6 million different types of parasites in vertebrate hosts alone. Admittedly, some parasites infect multiple different hosts, but nonetheless, their diversity is impressive. Then consider the 1.3 million known invertebrate animals, most of which also harbor multicellular and unicellular parasites, and then the more than 300,000 plants and their parasites, and the concept becomes slightly overwhelming. Sadly, despite the prevalence and importance of parasites to human and animal health, there are very few examples of commercially available vaccines against parasitic diseases. In this COVID pandemic era as we witnessed anti-viral vaccines go from bench to bedside in a matter of months, it is all the more remarkable that we have so few anti-parasite vaccines despite knowing of their importance for thousands of years.