The song is called "Per la Ricuperata Salute di Ofelia," which translates to "For the recovered health of Ophelia".
Rumors of Salieri's involvement in Mozart's death began almost immediately after Mozart's passing on December 5, 1791 just shy of his 36th birthday.
In 2001, Dr. Jan V. Hirschmann, an infectious disease specialist, reviewed childhood accounts and letters from Mozart to his wife and others placed the blame for his death on trichinosis from eating undercooked pork.
http://www.thedailybeast.com/articles/2016/02/17/does-a-song-prove-that-salieri-didn-t-kill-mozart.html
“I’m well again but it took five months! I can sing!
These eighteenth century quacks, can hardly do a thing!
Where’s Louis Pasteur when you need him?
Oh well, let’s get undercooked pork for Mozart and feed him!”
— being silly