Despite a floundering economy, restrictions on free speech and the incessant hostility of its powerful neighbour to the north, Cuba has developed a considerable research capability — perhaps more so than any other developing country outside southeast Asia. Whatever one thinks of its leader, Fidel Castro, it is worth asking how Cuba did it, and what lessons other countries might draw from it.

When Castro came to power in 1959, Cuba had almost no scientific infrastructure. Now it boasts a biotechnology industry that has produced effective drugs and vaccines of its own, a large and fairly influential scientific work-force, and a fledgling pharmaceutical industry with its sights set on export markets. The agricultural sector, in which small farmers benefit from partnerships with agricultural researchers, is also quite successful (see Cuban science: ¿Vive la revolución?).

Some of the reasons for Cuba's success are straightforward. The government has invested heavily in elementary and secondary education, and has attained developed-world standards of literacy and numeracy in its population. After university, large numbers of young scientists are sent abroad for training — once to its Communist allies, more recently to Europe and Latin America — and Cuba ensures, by fair means or foul, that they return home afterwards to work.

But one aspect of Cuba's scientific success is often overlooked. At various times, other Latin American nations such as Venezuela and Argentina have sought to build up science and technology by supporting a mixture of pure and applied research, a model similar to that established in wealthier countries. Cuba took a different approach: research there is ruthlessly applied.

Cuba's science is structured like a corporate research lab, except that its output consists of social outcomes not commercial products.

Cuba's state-sponsored science is structured like a corporate research laboratory, except that its output consists of social outcomes, rather than commercial products. If a project looks likely to earn foreign currency or meet the government's social objectives, it is backed to the hilt. Cuba's scientists have no funds for basic research, but they largely back their government's approach, in part because they have seen how it transformed health services in their country.

But the approach has many drawbacks. One concerns the constraints that it places on the movement of researchers. Castro's government maintains strict control on the movement of its citizens. Scientists fare better than most, and are frequently allowed to attend conferences or spend time working in foreign laboratories. Yet if they stay away for longer than permitted, they lose the right to return freely. This draconian approach to dealing with the threat of a brain drain is in breach of the Universal Declaration of Human Rights, adopted by the United Nations in 1948. Restrictions on free political expression in Cuba are also inconsistent with the declaration.

It is questionable, in any case, whether such restrictions serve any useful purpose for Cuba's government, given the obvious commitment of the scientists in question to their country's future. Just as questionable is the purpose served by the continuing US trade embargo on Cuba, which continues to isolate scientists and others on the island from their colleagues in the United States, including a large group of Cuban origin.

The embargo damages Cuban science and scientific collaboration in various ways. A Cuban proposal for dengue research, for example, won a $700,000 award from the Bill & Melinda Gates Foundation after international peer review. But the award has been held up for a year, lest the illustrious Microsoft founder, his wife and their fellow trustees be dragged off to the penitentiary for breaching the embargo.

Nature has consistently opposed scientific embargos, and strongly believes in research collaboration as a means of building bridges between nations that lack normal diplomatic relations. But there is a more specific issue here. When Castro dies, Cuba faces a period of volatility that could endanger key national assets, such as its science. In preparation for that day, both Havana and Washington should be acting now to wind down such cold-war artefacts as Cuba's travel restrictions and the US trade embargo.