Yes. These medical researchers are very good and very persistent so I trust them to do their detective work. They have always been my heroes.
For example, a recent claim is that they have found the earliest case of AIDS/HIV in humans. An excerpt:
"^By DANIEL Q. HANEY, AP Medical Editor, CHICAGO (AP)
Scientists have pinpointed what is believed to be the earliest known case of AIDS an African man who died in 1959 and say the discovery suggests the virus first infected people in the 1940s or early '50s...
The virus in the sample had degraded, but the scientists were able to isolate four small fragments of two viral genes. One gene holds instructions for assembling the outer coat of the virus, while the other is code for one of the proteins the virus needs to reproduce...
HIV mutates quickly. About 1 percent of its genetic material changes each year. So the scientists compared the genes from the 39-year-old sample of HIV with those carried by current versions of HIV."
https://www.cbsnews.com/news/the-earliest-aids-case/
Take time to read the (short) article. It is a credit to our medical/biomedical scientific researchers and explorers and a glowing tribute to what good science can do.