sentences:  The outbreak was labeled the "most alarming event" of 1971 by the United Nations Food and Agricultural Organization.Six years after the event, the newspaper "Newsday", citing untraceable sources, claimed that anti-Castro saboteurs, with at least the tacit backing of U.S. Central Intelligence Agency officials, introduced African swine fever virus into Cuba six weeks before the outbreak in 1971, to destabilize the Cuban economy and encourage domestic opposition to Fidel Castro.The virus was allegedly delivered to the operatives from an army base in the Panama Canal Zone by an unnamed U.S. intelligence source.