Apicomplexa

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Apicomplexan parasites extensively manipulate the host cell environment to establish infection, survive and proliferate

cryptosporidium

plasmodium

toxoplasma

theileria

Apical complex = allow them to establish and alter membranes

Cryptosporidium parvum: induction of massive host cytoskeletal actin remodelling (causes acute gastroenteritis in livestock)

*Recruits actin remodelling proteins which manipulate the structure of actin, generating an actin platform under the site of parasite attachment = involved in acquiring host cell nutrients and transport of vacuoles to the parasite

Plasmodium parasites:

Oxotrophs for purines (can't synthesise) - have to take from host (need purines to make nucleic acid) - use antigenic variation to persist

Toxoplasma gondii = remodels the PVM to prevent lysosomal fusion

Theileria Life cycle:

only eukaryotic cell that can evade other cells and cause proliferation

acts like a cancer cell (infected cells spread around body)

Animals die by drowning in own fluid

Transcription factor NF-KB is activated after infection and blocks apoptosis

Summary:

Apicomplexan parasites extensivley manipulate the molecular

environment of the host cells they infect to establish and survive

Plasmodium, Cryptosporidium, Toxoplasma and Theileria

Theileria annulata constitutively activates NF-kB and extensively manipulates the outcome of host cell transcription factor activation - to ensure survival of the proliferating infected cell

Manipulation may involve transport of parasite proteins to the host nucleus that bind DNA and alter bovine gene expression