Mary Rodgers and her team at Abbott, along with co-authors at the University of Missouri, on Wednesday announced their discovery of the first new subtype of the human immunodeficiency virus identified since 2000.

Their findings were published in an article published in the Journal of Acquired Immune Deficiency Syndromes.

"We're always looking for viruses," said Rodgers, who heads the Global Viral Surveillance Program at Lake County-based Abbott, a team of researchers who focus on identifying new strains of hepatitis and HIV and following trends in identified strains.

"I think a lot of people might not realise that there is more than one strain of HIV, and at Abbott we're making tests to catch all these different strains, so it's important that we know all the different types out there."

The newly discovered strain, called HIV-1 Group M, subtype L, was first collected in the 1980s in the Democratic Republic of the Congo, but there were only two samples that could be examined via gene sequencing.

Rodgers said Abbott researchers took note, but could not advance further toward positively identifying a new form of the virus; a third sample was needed to confirm the discovery.

In 2001, a sample that appeared to be similar was collected, but this time the sample couldn't be fully sequenced because the sample was too small.

Researchers at Abbott maintain a virus library with more than 78,000 samples, and the information about the potential new strain of HIV essentially sat as part of that archive until 2018.

"We always wondered if there would be another subtype," Rodgers said, "and we always thought that there might be another one out there if we just kept looking long enough."

Though researchers don't yet know how the new subtype may affect the body differently, the expectation is that it behaves in much the same way as other M group strains.

The discovery is important, said AIDS researcher Thomas Hope, professor of cell and developmental biology at Northwestern University Feinberg School of Medicine, to ensure tests can incorporate the new virus.

Current treatments for HIV, which can reduce viral load and prevent illness, are effective against variants of the virus, including the new subtype, meaning that a new strain is not a new public health crisis.

Abbott's tests can now detect this strain, and the company will share its research with other labs that are working to advance science around HIV.

Australian Associated Press