On the polycephalous cercariae of goat brain

I recently saw a Boer ram with a good body condition, that is, it wriggles its hind legs when walking, and another one often falls to the ground when it gets sick, and its hind limbs seem to be paralyzed. Both sheep are about 120 jin, which I think is brain polycephalosis. Can you express your views, if it is brain polycercaria, why only breed ram disease? Is this disease highly contagious? can it be cured?