There is this science fiction novel much similar or having a name similar to treasure planet. The things i can remember about the book are
- There were whale like creatures which were eventually discovered to be space-ships
- The main character was discovered to have a natural resistance to a particular deadly disease that was ravaging the known world
- There were pirates in the story line.
- There were alien creatures - some reptilian creature tagging along with the main character and the pirate crew.