A fierce new strain of HIV in Cuba is highlighting an old danger—of sleeping around without using any protection, CBS News reports. Researchers say the new HIV is a combination of strains (possibly from multiple sex partners) that more quickly invades cells and turns into full-blown AIDS. A study in Cuba looked at blood samples of 73 people recently infected with the "CRF19" strain, 52 of whom had AIDS, and compared them to 22 blood samples with AIDS from more ordinary HIV strains. The result: CRF19 patients had "abnormally high doses" of HIV, Eureka Alert reports. They also got AIDS only three years after infection, compared to the usual 10. In fact, CRF19 infects so quickly that patients may not realize they're sick until it's too late for antiretroviral therapy to help, Science Times reports.
This strain is more dangerous because it's better at grabbing onto human cells and eventually entering them. Typical HIV holds onto cells at one anchor point and advances to another as the virus progresses, giving the patient a few healthy years. But CRF19 moves faster, possibly because fragments combined from HIV subsets hold onto each other through an enzyme that helps the virus replicate. HIV's mutating ability is nothing new, but this one's a doozy—and may hold particular significance for Miami because "Cuba is local for Miami," a physician tells the Miami Herald. He's also troubled by the study's small sample size and the researchers' decision to not treat the patients. "It's unethical to wait until someone progresses" toward AIDS, when "they can no longer benefit from treatment," he says. (See how Craigslist personal ads are causing reported HIV cases to spike.)