The Cuban government-run newspaper Granma has published a letter signed by Fidel Castro, the first by the 86-year-old former president to be made public since July.
The letter, dated Wednesday, comes in the wake of rumors this month that prompted Castro's relatives to deny that his health had worsened.
Castro has not been seen in public since video images showed him greeting a visiting Pope Benedict XVI in late March, and the last of his essays known as "Reflections" was published June 19.
The letter, which appeared in Granma's online version Thursday, congratulates a Cuban medical institute on its 50th anniversary.
Castro, whose revolution seized Cuba in 1959, left office in 2006 due to a life-threatening intestinal condition. His younger brother Raul now serves as president.