Cholera is a potentially fatal, water-borne, gastrointestinal disease usually associated with poverty and inadequate sanitation. Some 600,000 people contracted the disease in Haiti after the 2010 earthquake, 8,000 of whom died.

It is not the sort of illness that you would expect to find in Cuba, where Fidel Castro’s 1959 revolution ushered in an era of free high-quality health care and excellent public health — or so we are often told.

The truth about Cuba, however, is that the revolution’s achievements were never as great as its propagandists claimed and that economic and social conditions on the island trail those of many Latin American countries Cuba once surpassed.

Cholera has returned to Cuba for the first time in more than a century. In three reported outbreaks since the summer of 2012, more than 600 people have been sickened and at least three have died, according to official Cuban data.

Of course, no one can say for sure whether these figures tell the whole story; they have been grudgingly admitted by a regime that is both totalitarian and eager to reassure the tourists upon whom it depends for hard currency.

Cuban authorities did their best to play down the bad news about cholera until visitors from Europe and Latin America — as well as a Cuban American from New York — contracted the disease this year and their cases made the press abroad.

Meanwhile, another kind of devastating truth about Cuba is influencing international public opinion in the form of “Una Noche” (“One Night”), a brilliant new indie film by first-time director Lucy Mulloy. After premiering at the Berlin and Tribeca film festivals in 2012, it is in limited release in theatres and available for download on iTunes.

Whereas the cholera epidemic bespeaks the decline of physical conditions on the island, “Una Noche” dramatizes the heartbreaking moral and psychological decay of the revolution’s subjects, especially Cuban youth.

Denied free expression, forced to hustle incessantly for life’s necessities, bombarded by propaganda and hounded by brutal police, young Cubans live in what Mulloy aptly calls a state of “nervous desperation.”

As one of her Cuban characters mutters, there only two things to do in Cuba: “sweat and f---.” Prostitution, sexual and otherwise, is the dominant mode of human interaction, but every transaction is ultimately rigged in favor of the authorities and the tourists whose dollars help fuel the regime.

The brothers in charge of this corrupt madhouse, Fidel and Raúl Castro, never appear in the film; they are not mentioned by name, much less criticized. One wonders if this was the price Mulloy paid for her apparently extensive access in Cuba. It hardly matters, since the audience knows who has been in power for the past 55 years and who is accountable for what Cuba has become.

The film’s turning point comes when Raul, a teenager eager to escape this crazy-making milieu, assaults a tourist he has caught having sex, for cash, with his mother. She needed the money for AIDS medicine.

With the police hunting him in every alleyway, Raul decides to flee to the United States. He and two companions take to the sea on a precarious raft fashioned from stolen styrofoam and bartered inner tubes. It is the same desperate course taken by tens of thousands of Cubans, many of whom have died in the attempt.

I won’t spoil the ending except to say that the movie culminates on a realistic note — which, since it’s about Cuba, cannot be a totally happy one.

Mulloy’s camera takes in Havana with the precision of a documentarian and the rhythm of a rapper. The result is a pulsation of conflicting images — fetid hotel kitchens, speeding police cars, street fights, parading hookers, jet-skiing foreigners — as hectic as the city itself.

She slows only occasionally, to linger on collapsed walls, patched-up roofs and crumbling sidewalks. It’s as if Havana had been hit by some massive artillery barrage — but we know this is the urban legacy of a half-century of communism.

“Una Noche” may do for nervous, desperate Havana what “Slumdog Millionaire” did for the shantytowns of Mumbai: portray it in a visual idiom that resonates with the new generation of pop-culture consumers and touches their hearts.

At least, I hope “Una Noche” has that kind of impact. Because another truth about Cuba is that Americans have grown too complacent about the Castro dictatorship. Enough already with the benign neglect. Enough already with the excuses — the U.S. embargo chief among them — and the phony promises of “reform.”

Enough already with a system, just 90 miles from our shores, that offers its people no sane alternative but escape.

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