Ridecamp: [RC] Polo Ponies

Does or has anyone know or done so themselves used Polo Ponies as endurance horses?  I have the ability to acquire one and wondered about them for endurance.  My QH gelding that I was training for a ride in Feb. contracted WNV and died.  He had been vaccinated but as you know it is only 90% effective.  He was 19 and such a good boy. he loved the trail.  It is a horrible way for them to go.  i put him down on Christmas Eve.  Thanks for any information.  Shawna