A vicious beaver that attacked an 8-year-old boy in New Jersey — before the fast-acting victim catapulted it back into a lake in a video that has since gone viral — has tested positive for rabies, authorities said. The rowdy rodent had already bitten multiple people at Lake Henry in the Continental Soldiers Park complex when it was filmed chasing the young boy out of the water and biting him while he was fishing with his family. While cops were investigating the attack, they alerted animal control personnel to the beaver, who found that it was exhibiting signs of possible illness, Capt. Michael Blondin of the Mahwah Police Department  told NorthJersey.com . The beaver has since tested positive for rabies, the Mahwah Township Health Department said in a  Facebook update  on Tuesday. Bizarre video captures the moment a beaver attacks an 8-year-old boy at a New Jersey lake. Facebook / Michael Noonan “Individuals who were bitten are currently receiving treatment.…