President William Henry Harrison gave the longest inaugural address in history, speaking outside in a cold Washington, D.C. snowstorm for an hour and 45 minutes. He died not long after from what people say was pneumonia brought on by the cold he caught while giving the address. Now some researchers at the National Institute of Health say that Harrison may not have died from pneumonia after all. In fact, Harrison along with Presidents James Polk and Zachary Taylor all may have died unexpectedly from typhoid in the 1840s due to contaminated water in the White House.

Both Harrison and Taylor died in office and Polk died not long after leaving office. According to the research, Harrison's own doctor disputed the pneumonia diagnosis in his well-documented medical journals Business News Insider outlined in a video.

"The disease was not viewed as a case of pure pneumonia," Harrison's doctor wrote. "But as this was the most palpable affection, the term pneumonia afforded a succinct and intelligible answer to the innumerable questions as to the nature of the attack."

"Although the president had fever, dyspnea and cough productive of blood-tinged sputum during the course of his illness, his pulmonary symptoms didn't arise until the fifth day of his illness and were intermittent rather than progressive thereafter," the study outlines. "His gastrointestinal complaints, by comparison, began on the third day of the illness and were relentless as well as progressive."

Essentially, Harrison had been complaining of constipation and had a distended belly. Despite laxatives and enemas, he had no relief for six days. It wasn't long after that the president's pulse fell and he died. He'd complained his whole life about persistent indigestion and in that day the most common fix was carbonated alkali. But drinking it offsets gastric acids in the gut which is there to kill off bacteria ingested and introduced into the stomach. So, the use of the alkali could have made his stomach more susceptible to potential infection.

Both Polk and Taylor also developed gastroenteritis while in the White House and Taylor died from it. Polk, however, recovered from it but was eventually killed by cholera just a few months later.

What gave them this problem boils down to a lack of proper sanitation and water filtration. DC didn't have a sewer system in the 1840s, it was more like a drainage system for storm and ground water. It wasn't until the 1850s that most of the people along Pennsylvania Avenue were piping in well water and sewage was being flushed into the nearest body of water.

The White House got its water from a spring just northeast of the building not far from what is now K Street. The White House is at an elevation of about 55 feet above sea level and the spring was about 60 feet. Further uptown, a few blocks northeast from Dupont Circle was a sewage dump that came from the higher elevations up the hill (approximately 80 feet above sea level). According to the study this would have been a bacterial free for all with salmonella typhi and salmonella paratyphi which cause typhoid and paratyphoid fever.

These bacteria could have easily found their way into the spring that delivered water to the White House and made their way into the drinking glasses of the three presidents.

Check out a full video on the NIH study from Business News Insider below: