And Dr. Greg Poland, director of the Vaccine Research Group at the Mayo Clinic, noted that the intensive care doctors he works with are in contact with other intensivists around the world who describe a bleeding, or hemorrhagic, lung infection. Poland said these doctors "are indeed seeing high viral, overwhelming viral, pneumonia, which then leads to hemorrhagic pneumonitis and severe respiratory distress syndrome; this has been requiring extraordinarily intensive therapy."
A spike in such severe cases could have big implications for hospitals, some fear.
"I have seen a number of these cases, with a number of deaths," said Dr. Christian Sandrock, medical director of the Intensive Care Unit at the University of California Davis Medical Center.
He added that while doctors can treat patients with much more specialized medical care now, if these very sick patients increase in numbers at hospitals, "These are the patients that are going to crush us."
Wire reports contributed to this story.