By early February, it had halted its shipments.One Russian oil tanker was allowed through the US blockade at the end of March, easing the crisis for about a month.Those supplies are now exhausted.Russia has sent another tanker, but it's not clear if it will be allowed to dock.For now, Betty travels around Havana to friends' homes who might have power, so she can use the internet to try to reach potential foreign visitors."Old Havana, once the main hub of visitors, is but a ghost town," she said"Prices have skyrocketed for the only still-standing businesses to stay afloat."Betty is plagued by another worry: a toothache that she says hospitals will be unable to address due to a lack of power and supplies.She is searching for treatment options on the black market, as Cuba's healthcare system plunges deeper into crisis.UN officials estimate there are 100,000 patients, including 11,000 children, waiting for surgeries delayed by power and supply shortages.Sewage infrastructure is breaking down, causing disease The supplies run out quickly, so people have to get up early or miss out."You can live without electricity," Lucia said, "but living without water is just not possible."Sporadic and small protests broke out last week as the island's energy reserves ran out.It was a sign of just how desperate people had become, says Havana-born Sebastian Arcos, who is now the interim director of the Institute for Cuban Studies at Florida International University (FIU)."This is a police state, a totalitarian society