I don't know...   I'm to dumb to know better but if the fox showed no outward signs of disease . foam/ blood in mouth, diarrhea on the southbound fur. Missing patches of fur etc.
 Then hell, I sure wouldn't eat it but I'd skin it. Atleast take the tail.
 Wear gloves, salt it and let it sit a while.
 If your spouse loves you , you can even use the washing machine.  Then salt it. 

 Maybe some kid in the neighborhood got a BB gun for Christmas. 
Kevin