Doctor's Review: Medicine on the Move

December 6, 2021
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Thinking outside the pox

Chickenpox and smallpox aren’t the same thing, but it took over 200 years to figure that out

As this year’s flu season shapes up into what’s looking like one of the worst to hit Canadian emergency rooms in a while, physicians everywhere are bracing themselves for the worst. Although the effectiveness of this year’s vaccine seems to be, justly or unjustly, bearing much of the blame for the outbreaks, patients would do well to remember that viruses — even innocuous ones like the flu and common cold — once ran rampant and unchecked in a world of unwashed hands and malevolent miasmas.

Of the grand old dames of viral history, smallpox was perhaps the most feared, with a fatality rate of about one third; residual effects left many survivors scarred, blinded and shunned for life. As horrendous a disease as smallpox was, our eradication of it through a global vaccination campaign stands as one of modern medicine’s most stunning accomplishments. Which is perhaps why, more than 20 years after the deadly disease was declared eradicated in 1977, nobody batted an eyelash when war was raged on the lowly chickenpox.

Chickenpox, after all, is considered more of a nuisance than a public health concern these days. Though, before the vaccine, incidence of chickenpox was roughly 90 percent by age 12, or 350,000 cases a year in Canada. It remains most dangerous to adults, especially pregnant women and those with suppressed immune systems, but incidence of the disease has fallen sharply with the introduction of the vaccine in 1999.

But imagine a time when all pustules looked the same, and when the slightest hint of the pox struck fear into the hearts of parents everywhere....

Looks can be deceiving

When the mummified corpse of Egyptian pharaoh Ramses V (d. 1157 BCE) was examined in 1898, it was discovered that the ancient ruler likely died of smallpox. His face and body, covered in smallpox’s characteristic lesions, mark the mummy as the earliest known victim of the disease. He wasn’t the first; pox viruses are thought to have migrated from rodent populations to human hosts in Africa some 10,000 years ago.

An ancient Ayurvedic text known as the Charaka Samhita discovered in India and dating to the turn of the Common Era is believed to contain the first mention of chickenpox in the literature. It was recognized as a different illness from smallpox, with a recommended treatment of a poultice of neem leaves and a dash of turmeric. Later, in Europe and North America, oatmeal became the go-to balm for itchy skin and rashes of all kinds, a treatment discovered by the ancient Egyptians and which, of course, remains a popular home remedy today.

Since the early symptoms of smallpox and chickenpox are quite similar, and smallpox itself is not universally fatal, it’s not surprising that the viruses were easily confused. Plus, there were so many poxes to contend with in centuries past — from the Great Pox (syphilis) to the more benign cowpox — that without the dubious diagnostic blessings of Google Images and resources like the Canadian Pediatric Society’s Caring for Kids website, the mere sight of a pustule, mosquito bite or runny nose sent some medieval mothers into a full-blown panic.

Is it or isn’t it?

The first inkling that smallpox and chickenpox were caused by completely different viruses came from the Italian physician Giovanni Filippo Ingrassia (1510-1580) a.k.a. the Sicilian Hippocrates. Giovanni, known for several important contributions to medicine, anatomy and virology — most notably his tract on scarlet fever and his osteological descriptions — gave the first description of varicella in the literature since the Ayurveda a millennia and a half earlier; he clearly distinguished it from scarlet fever.

But Giovanni was a reluctant hero to the pock-marked masses. Clinical work among the poor disgusted him and in describing his own practice, claimed not to be among those "base physicians who attend [to]... poor, sickly-looking people full to overwhelming with the coarsest and filthiest humours." He was, however, an able diagnostician and was confident he had it right when it came to this ubiquitous childhood illness being a distinct pathological entity.

The first mention of the term chickenpox came towards the end of the 17th century courtesy of English doctor Richard Morton (1637-1698). It’s unknown whether or not he knew of Giovanni’s work when he described chickenpox as a milder version of smallpox in 1684. It was another Englishman, physician William Heberden (1710-1801), who undertook the first independent study of the disease in 1767, in which he proved that varicella and variola were completely unrelated viruses. His paper, “On the Chickenpox” appeared in The Philosophical Transactions of the Royal Society and was also notable for its assertion that those who had chickenpox were granted immunity from ever contracting the disease again. Heberden’s work surely influenced Edward Jenner (1749-1823) in his momentous development of the smallpox vaccine in 1796.

A pox by any other name

Heberden, renowned for his kindness and virtue, was also closely connected to the man who defined chickenpox in a much more literal sense. Samuel Johnson (1709-1784), the 18th century’s most celebrated, curmudgeonly lexicographer was a patient of Heberden. The literary powerhouse described his physician as "Ultimus Romanorum, the last of our learned physicians." A high compliment from a man arguably most famous for his insults.

Most people assume that the term “chickenpox” implies foul play; that the characteristic spots on the face, trunk and limbs are reminiscent of either a newly plucked chicken or even the pecks of a chicken upon the skin, as suggested by English doctor and writer Thomas Fuller (1654-1734): “The smallness of the Specks, which [our Women] might fancy looked as tho' a Child had been picked with the Bills of Chickens.” Alternately, some suggest that the name derives from the term giccin, the Old English word for itching. One tenuous suggestion put for by another Brit, surgeon and legume-lover Thomas Fagge (1873-1939), was that the pox resembled “chick-pease.”

But the likeliest source is actually not a corruption of the “itching pox” or even of “child pox.” Samuel Johnson believed that the reason the disease had been coined “chicken” pox by some unknown source was that, quite simply, it was a cowardly, less fearsome incarnation of the somewhat ironically termed smallpox. He wrote in his 1755 dictionary that it was so called “from its being of no very great danger.” Chickenpox, by that point, was well on its way to becoming more of a nuisance and less of a nightmare.

You say varicella, I say variola

Despite the fact that Heberden had shown that the varicella and variola viruses were unrelated, people continued to believe otherwise. This led not only to fear of chickenpox, but also prevented some from being inoculated for smallpox believing that they had immunity conferred from chickenpox. It was our very own William Osler (1849-1919) who, decades after Heberden’s proof, helped change this impression once and for all stating that “There can be no question that varicella is an affection quite distinct from and without at present any relation whatsoever to it.”

At the time, however, even physicians, had trouble telling the difference. In one famous account of Osler’s skills as a diagnostician, he was called in to show his students what had been pronounced by several distinguished physicians at Johns Hopkins to be a severe case of chickenpox in an adult male. Interested, he gathered 30 or 40 students and doctors, and went to take a look. When the hapless resident pulled back the sheets to reveal the patient’s symptoms, a horrified Dr Osler exclaimed, “My God, Futcher, don’t you know smallpox when you see it?” Isolation measures were immediately put into place, the necessary vaccinations administered and a potentially disastrous situation was averted.

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