The real problem is that they may not be spending enough money to create mprw advanced drugs and while they may be doing this parisitology is on the low down with the mainstream us medical community.
Also by the way just because something is a 'vitamin' or 'natural' doesn't automatically make it better than everything else. Also you sound like someone trying to make money off d.e. and vitamin c by the way you push it.
They may be helpful for some things but that doesn't mean they are some magic cure for people with infections.