"Figure 3.29: Acanthamoeba spp. are waterborne parasites very com - mon in unchlorinated aqueous environments. Modification of work by Centers for Disease Control and Prevention. Public domain. Figure 3.30: An Acanthamoeba cyst. An Acanthamoeba trophozoite. Left: modification of work by Centers for Disease Control and Pre - vention. Public Domain. Middle, Right: Modification Figure 1, 3 from Lorenzo-Morales J, Khan NA, Walochnik J. An update on Acanthamoeba keratitis: diagnosis, pathogenesis and treatment. Parasite. 2015;22:10. https://pmc.ncbi.nlm.nih.gov/articles/PMC4330640 . CC BY"