“It can be a real challenge for diagnostic tests,” Mary Rodgers, a co-author of the report and a principal scientist at Abbott, said. Her company tests more than 60% of the world’s blood supply, she said, and they have to look for new strains and track those in circulation so “we can accurately detect it, no matter where it happens to be in the world.”

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said current treatments for HIV are effective against this strain and others. However, identifying a new strain provides a more complete map of how HIV evolves.

“There’s no reason to panic or even to worry about it a little bit,” Fauci said. “Not a lot of people are infected with this. This is an outlier.”

For scientists to be able to declare that this was a new subtype, three cases of it must be detected independently. The first two were found in the Democratic Republic of Congo in the 1983 and 1990.

The two strains were “very unusual and didn’t match other strains,” Rodgers said. The third sample found in Congo was collected in 2001 as a part of a study aimed at preventing mother-to-child transmission of the virus. The sample was small, and while it seemed similar to the two older samples, scientists wanted to test the whole genome to be sure. At the time, there wasn’t technology to determine if this was the new subtype.

So scientists at Abbott and the University of Missouri developed new techniques to study and map the 2001 sample. Rodgers said it was “like searching for a needle in a haystack,” and then “pulling the needle out with a magnet.”

It’s unclear how this variant of the virus may impact the body differently, if it does act differently at all. Current HIV treatments can fight a wide variety of virus strains, and it is believed that these treatments can fight this newly named one.

“This discovery reminds us that to end the HIV pandemic, we must continue to out think this continuously changing virus and use the latest advancements in technology and resources to monitor its evolution,” study co-author, Dr. Carole McArthur, a professor in the department of oral and craniofacial sciences at the University of Missouri, Kansas City, said in a statement.