[Parasitology] Diagnostic assay

[Hawash, Y.A.E.]

Dear ALL, 
I am going to do  a PCR assay for enteric protozoa that can affect human
. I wonder if any one can direct me to 
1-The best extraction method to be applied on clinical stool samples .
2- A good resource for enteric protozoa ( trophozoite ,cysts or oocysts
) in UK where I am studying.
Best wishes and complete regards,

Yousry