Working theory.
POTUS said "plague" many times today. Many, many times.
Plagues are not viruses; they are bacterial in nature.
Bubonic plague is one of three types of plague caused by bacterium Yersinia pestis. One to seven days after exposure to the bacteria, flu-like symptoms develop. These symptoms include fever, headaches, and vomiting. Swollen and painful lymph nodes occur in the area closest to where the bacteria entered the skin.
Flu like symptoms.
Stopped by taking HCQ, an anti-malarial medication.
And of course malaria is caused by a parasite.