How to defend against bloodmancers?

Bloodmamcers are an intelligent agglomeration of multiple microscopic organisms working in a colony.

Those organism can change shape to resemble a liquid or stand up in the shape of man being able to switch various cells around. Specifically they can change color perfectly to match the texture of clothes or human skin.

You may see a pond of water lying on the ground and the next second it morphs into a man.

Bloodmancers get their name because they can both enter humans through the veins and eat them from within, and also because they release some magical spores or air thingies which, when breathed in or coming in contact with the skin, make the person a slave to the bloodmancer.

The bloodmancer will be able to control from a distance (3 to 16 meters) the blood of the infected causing asphyxiation, moving limbs on their will, or simply increasing the blood pressure enough to blow up an artery.

The spores can travel for miles, and a skilled bloodmancer could infect an entire village from a large distance, then come and take control over the entire village either by literary commanding every single limb in their bodies like a puppet or extorting them in exchange of not being exploded.

How do normal humans living in a medieval fantasy setting defend themselves against being killed and/or enslaved by bloodmancers?