This vintage portrait features George Washington, the first president of the United States. (iStock)

Today is George Washington’s Birthday. It’s something of a political miracle that the man indispensable to the founding of his country came into the world just at the right time, in 1732, so that when he reached manhood, he was there when we needed him.

More miraculous still is that he survived so long, until 1799.

During the course of his 67 years on Earth, the father of our country survived smallpox, bouts of malaria, multiple infections and abscesses, tuberculosis, dysentery and in the first six months of his presidency, an extraordinarily painful boil “the size of two fists” accompanied by a fever.

So worrisome was his health at that point that some feared a “dreadful calamity,” and as James Madison wrote, a “crisis” in the affairs of the new nation, which had given no thought to anyone else as president. The presidency, indeed, was designed with Washington in mind.

“Were we to be deprived of his influence,” wrote Rep. William Smith at the time, “I much fear no other man could hold us together.”

As a young man, Washington fought with the British army during the French and Indian War. While not wounded, he became so ill and so close to being shot that before he returned home to Virginia, rumors were already circulating of his death.

“I have heard,” he wrote upon his return from battle in July, 1755, “a circumstantial account of my death and dying speech.

“I take this early opportunity,” he wrote his brother, John Augustine Washington, “of contradicting the first, and of assuring you, that I have not, as yet, composed the latter.

“But by the all powerful dispensations of Providence, I have been protected beyond all human probability or expectation; for I had four Bullets through my Coat, and two Horses shot under me; yet escaped unhurt.”

He had also fallen victim to dysentery, which produced extreme diarrhea in a man with hemorrhoids. “At first the stoic young aide tried to conceal the malady,” writes Washington biographer Ron Chernow, “but he soon found it so debilitating that he had to travel lying down in a covered wagon.”

It was not dignified. But he survived.

He had an iron constitution, which can only be fully fathomed by considering the state of medicine at the time.

“There was no well-defined concept of infection or immunity,” Anthony Fauci and David M. Morens wrote in a 2012 article in the New England Journal of Medicine, “no vaccines, almost no specific or effective treatments for infectious diseases and little idea that any treatment or public health measure could reliably control epidemic diseases … During Washington’s lifetime, infectious diseases were the defining challenges of human existence.”

Perhaps the most defining challenge to Washington’s health was his first known confrontation with infectious disease, when he contracted smallpox at the age of 19 while visiting Barbados. And as debilitating as it was, the immunity it conferred upon him would prove vital at another pivotal moment in American history nearly three decades later, a “powerful dispensation” for him and for the nation.

It was the spring of 1749 when George’s older half brother, Lawrence, contracted tuberculosis, a disease for which there was then no certain cure. In search of relief, he first traveled to England. Finding no reprieve in the treatments of English doctors, he returned to Virginia, where he only deteriorated further. He then decided to try Barbados, in hopes that the warmth there would help.

“Because Lawrence’s wife had just given birth to a daughter,” writes Chernow, it “fell upon George, nineteen, to accompany his thirty-three-year-old-brother, acting as both nursemaid and companion” on the 37-day voyage and while Lawrence got treatment.

Shortly after they arrived, the brothers received an invitation to visit Gedney Clarke, an uncle of Lawrence’s wife. Washington was reluctant to accept, because Clarke’s wife was confined with smallpox. Smallpox was “extraordinarily virulent; individuals exposed to the virus, which passes by contact, were almost certain to be infected,” wrote historian Jack Warren, unless through some previous exposure they developed an immunity to the disease.

As Virginia had not been touched by smallpox during Washington’s lifetime, he caught it. It’s not established that Mary Clarke, Gedney Clarke’s wife, was the source of Washington’s smallpox. But as Washington wrote in his diary on Nov. 16, 1751 he “was strongly attacked” with the lethal disease. Washington was housebound for 25 days with the painful pustules and fever and managed to survive.

Lawrence returned to Virginia and died of tuberculosis at his home in Mount Vernon in 1752.

Washington would soon become a soldier and “where soldiers go, plagues follow,” says the old axiom.

The American Revolution brought with it soldiers from England and Germany carrying smallpox, facing American forces largely unexposed to the disease, and therefore greatly vulnerable. By the fall of 1775, Boston, then under British occupation, “suffered from a widespread smallpox epidemic that threatened to spread throughout the ranks of Washington’s army,” according to the Mount Vernon digital research library.

The disease “spread like wildfire through the weakened soldiers and crowded army camps, leaving death and devastation in its wake,” writes Jeanne E. Abrams in “Revolutionary Medicine: The Founding Fathers and Mothers in Sickness and Health.”

“We should have more to dread” from the disease “than from the Sword of the Enemy,” Washington wrote.

Because Washington had already had smallpox, he was safe.

Despite the risks of spreading the disease by undertaking to inoculate the soldiers in the army he commanded, in 1777 he took the momentous decision to undertake the first mass military inoculation in history. By the end of that year, with some 40,000 troops inoculated, infection rates fell from 17 percent to 1 percent.

“It averted another health crisis within the Continental Army and dramatically altered the outcome of the Revolutionary War,” as Benjamin A. Drew wrote in JAMA Dermatology in July, 2015.

Washington, of course, lived on to become the nation’s first president, albeit one still plagued by the other diseases of his era and ultimately by the state of what was then modern medicine. White McKenzie Wallenborn, a physician, described his last days in an article supplementing the Washington papers at the University of Virginia:

On December 12th, 1799, George Washington in his 68th year of life, rode out around his farms on horseback from ten a.m. until about three p.m. The weather that day according to General Washington was snowing in the morning and about three inches deep. Wind at NE and mercury at 30 (30 degrees Fahrenheit). Continued snowing until about one o’clock, and at about four o’clock it became perfectly clear. Wind at same place-not hard. Mercury 28 (28 degrees Fahrenheit) at night. Colonel Tobias Lear, George Washington’s secretary, stated that the weather that day was bad, rain, hail, and snow falling alternately with a cold wind. When George Washington returned from his ride, the General’s neck appeared wet, snow was hanging from his hair, and he came to dinner without changing his dress (clothes wet?).

The next day, Friday December 13th, 1799, the General did not go out as usual for he had taken cold and complained of a severe sore throat. He did go out in the afternoon to mark some trees which had to be cut down. He now had hoarseness which increased in the evening. He spent the evening reading the papers, and when he met anything interesting, he read it as loud as his hoarseness would permit.

On the next day, Saturday the 14th, at three o’clock in the morning, he told Mrs. Washington that he was very unwell and that he had an “ague” (paroxysmal chills). It was observed that he could hardly speak and that he breathed with difficulty. At daybreak on the 14th, Colonel Tobias Lear came in and found the General breathing with difficulty and hardly able to utter a word intelligently. A mixture of molasses, vinegar, and butter was given but he (GW) could not swallow a drop and when attempted, he appeared to be distressed, convulsive, and almost suffocated. Later he tried to use a gargle of vinegar and sage tea but in attempting to gargle, he almost suffocated and when the gargle came back from the throat some phlegm followed.

At eleven a.m., his swallowing had not improved. After the last bleeding it was noted that the blood came “slow and thick” but there was no fainting (his physicians had ordered that he be bled a number of times in the course of his illness and an incredible amount about eighty two ounces or about five pints or units of blood were removed from him).

Doctors now believe Washington had acute epiglottitis, a life-threatening condition, caused by injury or infection, that causes the epligottis to swell, blocking the airways to the lungs. It was, and is still today, potentially life-threatening.

Today, Wallenborn writes, doctors would perform a tracheostomy, creating a surgical airway to allow air to flow to the patient’s lungs. While one of Washington’s three doctors suggested such a procedure, it was new and controversial and “might not have worked anyway,” Wallenborn writes.

His friend, Lear, described his last moments.

“At his bedside,” Lear wrote, “I reached for his hand. ‘My breath cannot last long,'” Washington told him. “‘I believed from the first that the disorder would prove fatal,’ he said. He seemed so perfectly resigned — dignified even — despite his gasping breaths …’I am just going,’ he said. After uttering some instructions, he whispered finally, ‘Tis well.’ And then he expired.”