Famous explorer Christopher Columbus, whom the U.S. celebrates today with “Columbus Day,” died at age 54 in 1506 after battling "reactive arthritis," an illness which is now treatable.

Columbus died of a heart attack caused by the disease, according to a study published on February 2007 by Antonio Rodriguez Cuartero, from the Department of Internal Medicine of the University of Granada.

Cuartero, working from Columbus’ diary and writings of his son, was able to assemble a nearly complete clinical history of the explorer, Cuartero told Mexican publication El Universal.

Columbus battled with symptoms such as burning pain during urination, pain of the knees and swelling and infection in the eyes known as conjunctivitis. All linked to the disease, according to his personal diaries and notes from contemporaries.

Frank C. Arnett M.D., a rheumatologist and professor at the University of Texas, said in 2010 that Columbus experienced “many months of debilitation on several occasions before becoming completely bedridden.”

“Reactive arthritis is an inflammation of certain joints that occurs several weeks after intestinal bacterial infections or after acquiring a sexually transmitted disease like Chlamydia,” he says. “It seems likely that he acquired reactive arthritis from food poisoning on one of his ocean voyages because of poor sanitation and improper food preparation.”

The exact cause of the illness is to date unknown. Certain genes can also make people more vulnerable to the disease, according to the A.D.A.M. Medical Encyclopedia.

Currently, doctors prescribe antibiotics if the patient has an infection and pain killers and anti-inflammatory pills to relieve symptoms.

Reactive arthritis can go away in a few weeks, a few months or it may become chronic, according to the encyclopedia.