Fidel Castro's signature appeared once again in the Cuban press on Thursday when he published a congratulatory message directed to an academic institution.

"Fidel's Message" to graduates of Havana's Victoria de Giron Institute of Basic and Preclinical Sciences appeared on the cover of the official dailies Granma and Juventud Rebelde and comes after days of rumors concerning a decline in the former president's health.

Castro's missive was also the lead story on Wednesday night's newscast on state-run television and appears on the government Web site Cubadebate.

It has been almost four months since the 86-year-old leader of the Cuban Revolution last published one of his "Reflections," the articles he began writing during his convalescence from the serious illness that forced him to hand over power to younger brother Raul Castro in 2006.

In addition, the most recent images of Fidel Castro were released back in late March, when he met with the visiting Pope Benedict XVI.

These circumstances and the fact that there was no known congratulatory message sent by Fidel Castro to his ally Hugo Chavez after the latter won the recent Venezuelan presidential election have fueled speculation in recent days about the Cuban's health.

In the message published on Thursday, Fidel recalls the opening of the institute on Oct. 17, 1962, after there had been an exodus from Cuba to the United States of the majority of the island's 6,000 physicians.

The inauguration of the institute coincided with the "hazardous" days of the Cuban Missile Crisis and the center had to serve as an "anti-aircraft fire unit," said Castro in his message.

Underneath the message appears, as he has habitually done with his "Reflections," Fidel Castro's signature, his complete name and the date and time, in this case "October 17, 2012; 1:20 p.m."

Last Friday, pro-government blogger Yohandry Fontana published remarks by one of Fidel's sons, Alex Castro, in which he said that his father "is well" and maintains a daily routine of reading and physical exercise. EFE