Since the start of the deadly AIDS epidemic in the 1980s, scientists have been working towards a cure. Now, they may be close to finding one.

　　Researchers have developed a method to cut the viral DNA from a person's infected cells. It is called CRISPR/Cas9 and it means the person could be virus-free.

　　DNA is a substance that carries genetic information in the cells of animals and plants.

　　This gene-editing took place in a scientific lab, but has not been tested on humans yet.

　　"It's a big step," said Kamel Khalili, Ph.D. He is lead researcher and chair at the Department of Neuroscience at Temple University in Philadelphia, Pennsylvania. He and his team made the discovery.

　　But more tests have to be done to know if it will be a cure for the millions of patients infected with the HIV virus, which causes AIDS.

　　Antiretroviral drugs have been doing a good job of keeping the AIDS virus from reproducing. Such a good job that levels of HIV are just about undetectable in infected people who take the medicine.

　　But even with the drugs, the virus stays in the body's "T-cells," which are T-lymphocytes. AIDS damages the immune system, hurting the body's ability to fight off disease.

　　So the drugs are kind of a "Band-Aid solution," Khalili explained. They keep the virus from growing. But they do not eliminate the memory of the virus from the cells.

　　And, the moment antiretroviral drugs are stopped, the HIV comes back to life and begins making more HIV, which is the AIDS virus.

　　Khalili and his team of scientists appear to have found a way to cut this viral DNA from infected people's cells.

　　In their lab, they took cells from people infected with the HIV virus. They removed the part of the cell that was holding the virus.

　　He said they had "in some cases, near 90 percent of the virus replication or production dropped in the patient samples after treatment in the laboratory."

　　Khalili and his team have not actually cured any patients yet. However, he believes this gene-editing technology could possibly cure AIDS.

　　"Elimination of the virus can lead to the cure." He said, "it's an exciting time, and the reason is the technologies are available and the methods are in place and our knowledge has increased."

　　"And hopefully, there will be funding to take us toward this exciting moment for developing the cure strategy by eliminating viral DNA using editing techniques."

　　He said that he hopes human tests could begin in two to three years. But that depends on funding.

　　The work was published in the journal Scientific Reports.

　　HIV/AIDS has been a devastating disease since it was first discovered in the early 1980s. Since then, the World Health Organization says almost 78 million people have been infected with the HIV virus. About 39 million people have died of HIV/AIDS.

　　At the end of 2013, 35 million people worldwide were living with HIV, according to the WHO.

　　Sub-Saharan Africa is the most affected by the virus. Nearly 71 percent of people in the world who live with HIV are in Sub-Saharan Africa.

　　And while the drug therapy can control the virus, not everyone infected can get or afford it. Also, some who take it report side effects.

　　I'm Anne Ball.

　　Jessica Berman reported on this story for VOANews. Anne Ball adapted this story for Learning English. Kathleen Struck was the editor.

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