Venezuela’s brewing economic troubles and high crime rates have been prompting Venezuelans -- particularly young professionals -- to emigrate by the thousands in recent months. But Cuban doctors stationed there are also getting in on the exodus: The number of Cuban medical professionals defecting from their posts in Venezuela has ballooned in the past year, and many of them are winding up in the United States.

The U.S. has been a prime destination of Cuban defectors in the health care sector, with the help of the little-known Cuban Medical Professional Parole Program, launched by executive order under President George W. Bush in 2006. According to the U.S. Citizenship and Immigration Services agency, the number of medical workers from Cuba who have come to the U.S. under that program quadrupled in the last four years, aided heavily in the last year by defectors from Venezuela.

Since September 2013, some 700 Cuban medical professionals have abandoned their stations in Venezuela, up from 300 the previous year, according to Solidarity Without Borders (SSF), a nonprofit organization based in Florida that helps Cuban health care workers transition their careers in the United States. The U.S. granted 1,289 visas to Cuban medical professionals in fiscal year 2014, a record, with 1,438 visas granted to defectors from Venezuela in the past four years.

“Worsening conditions in Venezuela push defection up,” SSF president Dr. Julio Cesar Alfonso told Venezuelan newspaper El Universal. “Insecurity, low wages, labor exploitation and control over private life continue to be the main causes.” In Venezuela, it’s common for defectors to escape first through Colombia with the help of smugglers before applying to the U.S. parole program for a visa.

Many Cuban medical professionals opt to participate in the country’s infamous international medical programs for higher wages offered in other countries; in Brazil, for instance, doctors are reportedly paid $1,125 a month, while in Cuba, the government recently raised doctors’ salaries to around $67. But some doctors have also reported being coerced by Cuban authorities to work in Venezuela’s poorest and most insecure neighborhoods without adequate protection or enough money to eke out a decent living. Alfonso told El Universal Cuban medical workers in Venezuela often only receive around $100 while the Cuban government reaps most of the financial rewards from the deal. “They cannot refuse to work, they are poorly paid and no one says a word,” he said.

One defector named Manuel who spoke with the Los Angeles Times in September said he was only paid $20 a month in Venezuela, an amount that “was not enough to pay even for food and transportation, much less a telephone call to Cuba now and then.”

U.S. congressional hardliners on U.S. Cuba policy, including Rep. Mario Diaz-Balart, R-Fla., have decried the program as forced labor. “Cuban doctors are hastily trained, poorly equipped and forced to work in dangerous conditions while most of their pay is siphoned to the Castro dictatorship,” Diaz-Balart said last month.

But in many other cases, such as with Cuba’s medical missions in West Africa to combat Ebola, observers say that Cuban medical personnel are there on their own accord. The U.S. State Department also stated in its 2014 human trafficking report that “reports of coercion by Cuban authorities in this program do not appear to reflect a uniform government policy of coercion; however, information is lacking.”

Cuba does not have official figures on how many doctors it has sent on international medical missions, which have been in place since the early 1960s. But the programs have been a hallmark of Havana’s foreign policy under the Castros. The so-called oil-for-doctors agreement between Cuba and Venezuela forms the foundation of their close relationship and is generally a win-win for the governments involved: Cuba is able to raise its humanitarian profile internationally while also receiving an estimated $3.2 billion per year in discounted Venezuelan oil, and Caracas gets trained medical professionals to boost the government’s social agenda.

Cuba has also sent thousands of medical professionals to Brazil under the “Mais Medicos” (More Doctors) program launched last year, a move that provoked the ire of health care unions in Brazil. Earlier this year, two doctors defected from the Brazil program and moved to the U.S., saying their salaries were only a fraction of what other foreign doctors in Brazil made and accusing the Cuban government of pocketing most of the pay.