Are Colpodella Species Pathogenic? Nutrient Uptake and Approaches to Diagnose Infections

species are free-living protists phylogenetically related to apicomplexans. sp. have been detected in human and animal tissues, as well as in ticks and biting flies. The trophozoite and cyst stages of species can be distinguished from stages of the prey using Sam-Yellowe's trichrome staining. species obtain nutrients by attaching to their prey, aspirating the prey's cytoplasmic contents into a posterior food vacuole and encysting. It is unclear whether both trophozoite and cyst stages are present in human and animal tissues. Molecular techniques have detected species in human blood, cerebrospinal fluid, and in ticks and flies. However, no morphological information was reported to aid life-cycle stage identification of species. This review discusses the increased reports of species detection in animals and in arthropods and the need to identify stages present in human and animal tissues. We previously used Sam-Yellowe's trichrome staining to identify life-cycle stages of sp. In this review, we examine the reports of species detection in human and animal tissues to determine whether the identification of species represents true infections or contaminations of samples collected during routine surveillance of piroplasm infections in animals and arthropods. This review also aims to provide insights regarding , nutrient uptake, and the survival of sp. within humans, animals, and arthropods, as well as whether the attachment of trophozoites to cells occurs in tissues leading to myzocytosis and endocytosis.