By Dave Graham
PENAS BLANCAS, Costa Rica (Reuters) - In the week Cuban migrant Lenin Rivacoba has slept rough on Costa Rica's border with Nicaragua, he was briefly blinded by tear gas, lost hearing in one ear and is now almost out of money.
But Rivacoba, whose first name was given in honor of Soviet revolutionary Vladimir Lenin, says he would rather perish than return to his family in Cuba because it would mean giving up on their dream of forging a new life in the United States.
"It's get there, or die," said Rivacoba, a 30-year-old teacher and father of two whose grandmother sold her house for $5,000 to pay for his passage to the United States. "I can't return. They're waiting for me to start sending money back."
Rivacoba is part of a tide of Cubans rushing to the United States because they fear the recent rapprochement between Havana and Washington could end preferential U.S. policies for Cuban migrants.
While migrants from across Latin America struggle to get green cards and many live illegally in the United States, fearful of deportation, Cubans receive residency with ease under the U.S. Cuban Adjustment Act of 1996.
Along with over 1,000 tired but determined Cubans, Rivacoba has been stranded here since Nicaragua's leftist government, a close ally of Cuba, refused to let them cross the border last week.
Blocking traffic at the border in a bid to force Nicaragua to relent, many of the Cuban migrants say they sold their belongings to make the journey and that there can be no turning back.
From babies to grandparents, blacks to whites, they have turned the Penas Blancas border station into a temporary shelter with makeshift beds, piles of luggage and improvised washing lines. Hundreds of others are being housed in buildings around the small town of La Cruz nearby.
Since U.S.-Cuban ties began to thaw in December, the number of Cubans heading through Central America has leapt.
According to U.S. Customs and Border Patrol data published by the Pew Research Center, 27,296 Cubans entered the United States in the first nine months of the 2015 fiscal year, up 78 percent from 2014.
Two-thirds arrived through the Border Patrol's Laredo sector in Texas, though the number arriving mostly by sea to the Miami sector also surged, more than doubling from the previous year to over 7,000, the figures showed.
The vast majority at the Nicaraguan border say they flew from Cuba to Ecuador and then started the trek north through Central America. A few said they had crossed the Caribbean to Venezuela via Trinidad and Tobago.
All of them said they left Cuba to improve their economic lot, and a substantial number were also worried the U.S. "wet foot, dry foot" policy could soon end.
"People say it's going to change in January," said Yahumara Ramirez, a 39-year-old nurse who was deported back to Cuba in 2013 during her first attempt to reach the United States.
Under the policy, Cubans who set foot on U.S. soil can stay, while those captured at sea are sent back.
Cuba's Communist government on Tuesday blamed U.S. Cold War-era immigration legislation for the migrant crisis, but U.S. officials have repeatedly said there are no plans to change it.
Many of the stranded Cubans here have followed a route snaking from the Colombian city of Ipiales, through Cali and Medellin and into Panama via Puerto Obaldia.
The Colombian section has become notorious, with tales widespread of extortion by both police and coyotes - the smugglers used by migrants to evade authorities.
Alberto Perez, a 24-year-old aspiring actor, said he had to pay officials bribes of $20 or more 18 times crossing Colombia.
"They say it's for 'collaboration'," he said wryly, adding that police patrols would radio on ahead to colleagues to alert them when Cubans were coming.
Fellow migrant Johannes Burgos, 26, said he and 12 others were forced to pay $1,500 each to a group of coyotes who threatened them as they were entering Panama.
The migrants said Panama and Costa Rica treated them well, but they cursed Nicaragua, whose President Daniel Ortega has been an ally of Cuba's government since the Cold War era, for closing its border.
Earlier this month, Nicaragua was still open to migrants. But Costa Rica's temporary closure of its border with Panama after the bust of a human trafficking ring unleashed a surge northward when it was reopened last weekend.
Nicaragua responded by sealing the border with troops.
Frustrated Cubans staged protests at the crossing, and this week trucks stretched back more than 4 km (2.5 miles) into Costa Rica.
Costa Rica has called for a regional summit to create a corridor to let the Cubans pass, arguing they will otherwise fall into the hands of smuggling gangs.
Rivacoba and hundreds of others had already crossed some 5 km into Nicaragua on Sunday when police appeared and abruptly forced them back using tear gas, he said.
Police also fired shots into the air, and one went off so close to Rivacoba's ear his hearing is still impaired.
For all the frustration over Nicaragua, most of the Cubans' anger is aimed at the Cuban government, which they accuse of cronyism, mismanaging the economy and limiting free speech.
Fanning his 10-month-old son with a towel in the stifling heat of a Red Cross border shelter, Yordanis Boza said even if detente between the United States and Cuba helps the economy, it will not happen fast enough for his wife and two children.
"If you work for a year in the United States it's like working for 10 years in Cuba, or more," the 28-year-old said.
(Additional reporting by Enrique Pretel; Editing by Simon Gardner and Kieran Murray)