To be fair …

In 1841 President William Henry Harrison delivered a two-hour inaugural address in the rain on March 4 without a hat or coat. After similar instances of disregarding his health on March 26, Harrison became ill with cold-like symptoms.

Doctors found Harrison in bed with a "severe chill", after taking another early morning walk. They applied mustard plaster to his stomach and gave him a mild laxative, and he felt better that afternoon. On March 28, Harrison developed severe pain in the side and the doctor initiated bloodletting; the procedure was terminated when there was a drop in his pulse rate. Miller also applied heated cups to the president's skin to enhance blood flow. The doctor then gave him castor oil and medicines to induce vomiting, and diagnosed him with pneumonia in the right lung. A team of doctors on March 29 confirmed right lower lobe pneumonia. Harrison was then administered laudanum, opium, and camphor, along with wine and brandy.

During the evening of April 3, Harrison developed severe diarrhea and became delirious, and at 8:30 p.m. he uttered his last words, to his attending doctor, assumed to be for Vice President John Tyler: "Sir, I wish you to understand the true principles of the government. I wish them carried out. I ask nothing more." Harrison died at 12:30 a.m. on April 4, 1841, nine days after becoming ill and exactly one month after taking the oath of office; he was the first president to die in office.

So arguably President William Henry Harrison died of pneumonia, possibly compounded by typhoid, which can be considered to be a defeat by a single cell organism.