By Frances Kerry
HAVANA, Oct 5 (Reuter) - Fidel Castro's leadership of Cuba into the 21st century will come under the spotlight this week as the ruling Communist Party holds a congress expected to opt for continuity in political and economic strategy.
Authorities are portraying the Oct. 8-10 Fifth Party Congress as an occasion to mark support for President Castro's 38-year-old revolution -- now a post-Soviet era hybrid of one- party socialism with some capitalist trimmings -- rather than a moment for radical departures.
"We have to think of the congress as a reaffirmation of the political thinking of the revolution,'' Vice-President Carlos Lage told reporters on Saturday.
The congress, the first full party gathering since 1991, is bound to highlight the role of Castro, 71, even if the question is not voiced by the 1,500 delegates and 250 guests at Havana's Convention Centre.
The subject of Castro's health is virtually taboo in Cuba at official levels.
But in recent months foreign diplomats have speculated that the veteran revolutionary, who took power after his rebel army ousted former dictator Fulgencio Batista in 1959, is ill or at least starting to show his age.
Castro has cut back his public schedule this year and did not speak publicly for nearly five months from early April, prompting rumors in Miami and elsewhere abroad that he had died. The Cuban Foreign Ministry denied the rumors, saying he was in "excellent health.''
Castro finally appeared on Sept. 1 to open the school year with a speech that included jokes about the rumors.
But foreign diplomats who attended a reception he gave late last month said they were surprised at his gaunt appearance.
Castro occupies all the key posts in the country -- Commander in Chief of the Armed Forces, Communist Party First Secretary and President of the Council of State and Council of Ministers.
Foreign diplomats have speculated that at some stage he may want to ease his workload by giving up one post.
They say if this occurs he might create the post of Prime Minister and possibly hand it to Lage, 45, who has overseen the country's economic reform process and has often assumed a prominent public role in recent years.
Castro's officially designated successor should he die or become incapacitated is his brother Raul Castro, 66, who is vice-president, defence minister and deputy head of the party.
Fidel Castro has in the past addressed the longer-term succession issue, saying a new generation of Cubans are ready to take up the baton of revolution.
In what Lage called a process of "natural renewal,'' the congress will elect a new Central Committee and Politburo and some new, younger faces are expected.
The gathering will unequivocally state commitment to one-party socialism, however, approving a political document that argues Cuba has no choice but its current system.
The document shakes an angry fist at the United States, Cuba's principal foe since 1959, arguing it poses a greater threat than ever to the country's independence. Washington last year tightened its 35-year-old economic embargo in an effort to step up pressure for change.
Delegates will also approve an economic document that is expected to consolidate cautious liberalization begun four years ago at a time of crisis caused by the collapse of the Soviet Union. The reforms have pulled Cuba out of the worst of the crisis but authorities are still wary of letting the small private sector evolve.
The document, which has not been made public ahead of the congress, is likely to make plain the state will continue to control a lion's share of the economy.
"It ratifies the socialist nature of economic policy even with the introduction of some market elements and certain capitalist practices,'' the party newspaper Granma said.
15:06 10-05-97