Apicomplexa
noun plural
Api·com·plexa
ˌā-pi-kəm-ˈplek-sə, ˌa- 
: a taxonomic group and especially a phylum of diverse parasitic protozoans that have a complex life cycle usually involving both asexual and sexual generations often in different hosts, that move by gliding or bending, and that include the causative agents of malaria, toxoplasmosis, and cryptosporidiosis
Note: The group Apicomplexa was proposed for use in place of Sporozoa because the infective stage (sporozoite) is not always contained within a spore. While Apicomplexa and Sporozoa are often considered synonymous, not every species in the group Sporozoa is included in Apicomplexa. One uniting feature of members of Apicomplexa is a specialized complex of organelles at the apex of the cell which facilitates penetration of a host cell during its infective stage.
apicomplexan
noun
Many apicomplexans are of medical or veterinary importance, including Plasmodium, Babesia, Toxoplasma … and Eimeria.
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Mitchell S. Abrahamsen et al.
Mitchell S. Abrahamsen et al.
Cite this Entry
“Apicomplexa.” Merriam-Webster.com Medical Dictionary, Merriam-Webster, https://www.merriam-webster.com/medical/Apicomplexa. Accessed 31 Oct. 2025.
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