(ABC News) -- Swedish scientists have identified a new strain of HIV that appears to progress much faster than most previously identified variations of the virus.
The new strain, known as A3/02, is a recombinant, meaning it is a cross between two previously identified HIV strains. Writing in the Journal of Infectious Diseases, Lund University researchers said that the infection moves from HIV to full-blown AIDS in about five years, nearly two to two and a half years faster than most previously known strains.
So far the new infection seems confined to West Africa. But experts fear that recombinants are becoming more common and could start to spread globally, especially to highly mobile regions such as Europe and the United States. The researchers said recombinants develop faster than the "parental" strains they spring from, though fortunately, this latest strain seems treatable with existing drugs.
An HIV diagnosis changes to AIDS when a person's white blood cell count dips below 200, according to the Centers for Disease Control and Prevention.
Phalguni Gupta, a professor of infectious diseases and microbiology at the University of Pittsburgh School of Graduate Health, said that most clinicians also consider a diagnosis of AIDS when someone with HIV develops a serious infection such as pneumonia, cancer or a wasting syndrome characterized by severe weight loss, diarrhea and high fever. In poorer regions such as West Africa, tuberculosis is the leading cause of death among people with HIV.
Gupta, however, said it was misleading to say that this new strain was the most aggressive form of AIDS yet known.
"There are some HIV types here in the United States that take as little as two years to develop into AIDS," he noted.
This information is particularly troubling in light of a new Centers for Disease Control and Prevention report that found that since 2005, there has been a 48 percent increase in unprotected anal sex in the U.S. among men who have sex with men. Men who engage in risky sexual behavior are often unaware of their positive HIV status, the report found.
Gupta said the new West African strain needs to be monitored to see if it transmits more readily than other types of HIV. This is a question the researchers haven't yet explored.
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An estimated 34 million people globally have been diagnosed with HIV, according to the World Health Organization. Since the epidemic began more than 30 years ago, the infection has claimed more than 33 million lives, the CDC estimates.
There are glimmers of hope. Treatment, prevention and awareness have come a long way since the since the early days of the AIDS epidemic.
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