Interesting stuff lineup. I will mention that in the case of my own parasites, there is a stage which I believe is designed to be picked up by macrophages and transported. I have also seen the sporozoites, which are very interesting. They resemble bacteria, and would be in no way identifiable, unless seen exiting the oocyst.
So, as I have always maintained, it is the intracellular stage that is the problem.
If you can stimulate antibodies against the oocysts, I think that would be a major gain. Shroom