CHICAGO — Abraham Lincoln has been dead for 142 years, but he still manages to make medical headlines, this time from doctors who say he had a bad case of smallpox when he delivered the Gettysburg Address.

Physicians said last week that Lincoln might have survived being shot if today’s medical technology had existed in 1865. Last year, University of Minnesota researchers suggested that a genetic nerve disorder rather than the long-speculated Marfan syndrome might have caused his clunky gait.

“If you play doctor, it’s difficult to shut down the diagnostic process” when reading about historical figures, an immunology specialist and professor emeritus at the University of Texas Medical Branch in Galveston, Dr. Armond Goldman, said. He and a colleague “diagnosed” serious smallpox in Lincoln after scouring historical documents, biographies, and old newspaper clippings.

Their report, presented at a Baltimore conference, appears in this month’s Journal of Medical Biography.

“Lincoln is such a famous figure in American life that people are just automatically drawn to him,” Dr. Goldman said.

Heart illness, eye problems, and depression are among other ailments modern-day doctors have investigated in the 16th president.

But smallpox is the one that might come as the biggest surprise to the general public, especially if Lincoln had it when he spoke at Gettysburg.