The 25-year-old laboratory researcher at San Francisco Veterans Affairs Medical Center died Saturday morning after asking friends to bring him to the hospital, the San Jose Mercury News reported Thursday.
The man, whose name has not been reported, was working to develop a vaccine for highly infectious bacteria linked to meningitis and septicemia, both deadly bloodstream infections, at the VA hospital.
Harry Lampiris, chief of the VA hospital's infectious diseases division, said the man left work Friday evening and "had no symptoms at all."
About 2 hours later, however, he told his girlfriend he was feeling sick with a headache, fever and chills, Lampiris said. On Saturday, his symptoms worsened and he developed a body rash.
He asked friends to bring him to the hospital and when he arrived, he was unconscious and had no pulse. The man died later that morning.
Officials believe the man died of septicemia, a bloodstream inflammation that causes bleeding into the skin and organs.
Those who worked with the researcher said he followed the rigorous safety precautions when dealing with the germs he was studying.
"His co-workers felt he was highly competent and that he was adequately supervised to do the level of work," Lampiris said.
The San Francisco Department of Public Health, the California Occupational Safety and Health Administration and the U.S. Centers for Disease Control are trying to determine how the man became infected with the disease and identify all those who came in contact with the man to ensure they get preventive antibiotics.
"We're not certain how this death happened, but hopefully the investigation will turn up some answers to help prevent it from ever happening again," CDC spokeswoman Alison Patti said.