Context

Apicomplexa are parasites responsible for diseases with a high economic and sanitary impact in animal health (toxoplasmosis, neosporosis, babesiosis, cryptosporodiosis, etc…), but in human health as well.  Currently, few vaccines against these infectious diseases are available in veterinary medicine and none is in human medicine.

Nowadays, available veterinary vaccines are mostly of 2 types:

• live and attenuated vaccines obtained through several consecutive culture cycles on cell lines or in animals.  Generally, these vaccines are very effective, the immune response they trigger being very similar the one caused by a natural infection.  Nonetheless, the origin of their attenuation is mostly unknown and a return to full virulence is a major risk to be handled and that prevent their use in human beings,
• inert vaccines made of killed parasites or of protein subunits.  Commonly, these vaccines are very safe, but poorly effective.