Colpodella spp. are phylogenetically related to apicomplexans such as Plasmodium spp., Babesia spp., and Cryptosporidium spp. Colpodella spp. are free-living protists that prey on bodonids, ciliates, and algae using myzocytosis. Colpodella spp. cause human and animal infections known as colpodellosis, with transmission via ticks across different geographic areas on different continents. Colpodella spp. DNA has been detected in ticks, the biting fly Stomoxys indicus and vertebrate samples using polymerase chain reaction (PCR). Ticks transmit zoonotic pathogens, and the identification of Colpodella spp. in animals poses a major public health risk due to human and animal encounters exposing humans to tick bites. However, it is unclear if ticks are confirmed vectors for Colpodella spp., since tick vector competence and capacity for Colpodella spp. transmission has not been experimentally demonstrated. Human cases of colpodellosis have involved three cases of blood infection, a fourth case of tickborne infection, and a fifth case of urinary tract infection. In this narrative review, the occurrence of Colpodella spp. in ticks that transmit zoonotic pathogens will be reviewed. Differences in the disease presentations and symptoms of colpodellosis in tickborne infections will be discussed. The pattern of Colpodella spp. coinfections with piroplasms and Cryptosporidium spp. will be evaluated. The pressing need for morphological identification of Colpodella spp. to assist proper characterization of the different species identified in arthropods and vertebrate hosts will be highlighted.
Tobili Y. Sam-Yellowe (2026) studied this question.