Sporozoans (Apicomplexa) - Protozoa

 The sporozoans (Apicomplexa)

Members of this group are all parasitic, infecting a range of vertebrates and invertebrates. They have complex life cycles involving both haploid and diploid phases and infecting more than one host. Probably the best known is Plasmodium, the causative agent of malaria, which spends part of its life in a species of mosquito (Figure 9.15). Sporozoans are characterised by a spore-like stage called a sporozoite, which is involved

in the transmission of the parasite to a new host. The tip of the sporozoite contains a complex of structures that assist in the penetration of the host’s tissues. Unlike the protozoans discussed above, sporozoans are generally non-motile, and absorb soluble nutrients across the cell surface rather than ingesting particulate matter.