For example , on 16 April 2007 , Knut took a break from his display because of teething pains , but reports said that he might have an unknown sickness . For example , on 16 April 2007 , Knut was removed from display due to teething pains resulting from the growth of his right upper canine tooth , but initial reports vaguely stated that he was suffering from an unknown illness and subsequently put on antibiotics .