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Chapter 38: Bad Apple

Updated: Apr 17

Lyme disease has been around since before mankind, and certainly before proverbs about bad apples, which first surfaced in the English language around 1340, conveniently around the time of Sir Lancelot and his ill-fated quest for the Holy Grail. And, fittingly, Guinevere’s “bad apple” stumper of a brainteaser. To complete the metaphor, as the fruit decays, these rotten apples produce ethylene gas, accelerating the aging of nearby apples. If you’ve been paying close attention, you’ve already noticed a few of the bad apples that are contaminating the MS gradient theory—locations that outright contradict the presumed association between MS and sunlight. But there is one location, ironically about the size and shape of Connecticut, that befits the quest of one Sir Lancelot: a pulsing Caribbean island known not for its bad apples, but for its beaches, its rum, and its now iconic naughty rabbit, international rapping sensation Bad Bunny.

Welcome to the United States territory known as Puerto Rico, the land of zero blacklegged ticks. And home to an unseen and unrealized Lyme disease epidemic.

Old San Juan, Puerto Rico

At first blush, the idea that P.R. is awash in undiscovered cases of a tickborne illness—when the island has had not a single reported case of Lyme, at least according to the CDC—sounds positively ludicrous, and we’re not talking about the rapper Christopher Brian Bridges and his sunshine-infused 2017 single “Vitamin D” (seriously, he apparently cares about the health of his women). But the science tells a starkly different story. And it doesn’t take a high-powered microscope to see the telltale signs of the existence of spirochetes, typically so small they are measured in millionths of a meter.

Throughout his career, acclaimed NIH and Mayo neuroepidemiologist Dr. Kurland pushed the idea that rigorously examining disease occurrence—where, who, and how often—would lead to more insights than individually scrutinizing patients. Yet the allure of investigating a disease by focusing on it at a microscopic level, leveraging all available advanced technology, has proven over time to be too powerful to resist. Analyzing the details revealed by ever more insightful MRIs, spinal taps and blood draws produce immediate, measurable, tangible results. If only researchers had bothered to look up from the minutiae.

In May of 2023, our intrepid MS specialist Dr. Beaber fortuitously put together a world map of MS prevalence for one of his popular videos, stitching together a number of MS epidemiological studies. The numbers appear to make no sense in support of the gradient theory, and squinting to account for oft-suspected variables (Western diet, sunlight) doesn’t help. Syracuse, NY, boasts some of the world’s highest MS rates at 1 out of every 222 people and sits at a longitude of 43 degrees. So why is the prevalence in Alberta, Canada, straddling the much more northern 54-degree mark, actually somewhat lower, at 1 out of every 280 people? Jump across the Atlantic and the numbers get just as squirrely. Caseloads in France, at a latitude of 46 degrees, log in at 1 out of 2,500—more than 10 times fewer than Syracuse despite its higher latitude. To even sniff the type of prevalence in Syracuse on this side of the world, one has to travel to the latitudinal nosebleeds of Greenland, 72 degrees latitude, and even then, the rate is “only” 1 out of 370. But nothing compares to the ultimate outlier, our second twist.

Standing out like a pimple on prom day on Dr. Beiber’s research map lies Puerto Rico, latitude 18 degrees, with the prevalence of MS checking in at a modest 1 out of 1,000. Compared to areas around the continental US, the gradient appears to hold. Syracuse is worst, Southern California is better (1 out of 420), and P.R. is noticeably better still. As we head toward the equator, rates drop precipitously: Panama is 1 out of 19,000, Colombia is 1 out of 23,000, and the country named after the dividing line, Ecuador, is 1 out of 25,000. But start spinning the globe and the latitude gradient doesn’t just start to wobble like an off-kilter ceiling fan, it becomes untethered nonsense.

MS prevalence worldwide map in select regions

Puerto Rico is nearly the same latitude as Thailand (only two degrees of difference), yet the odds of getting diagnosed with MS there are Powerballesque: 1 out of 130,000. Rates in Africa are equally puzzling. Areas practically straddling the equator sit in the 1 out of 30,000 range, which fits. But far more confounding? Travel closer to the South Pole, and while the prevalence of MS in white South Africans climbs to 1 out of 3,900, the prevalence in Black South Africans craters to 1 out of 454,000, among the lowest odds on the planet. And it’s a full 29 degrees removed from the equator.

Do you hear that noise? That sputtering, coffee-spewing chorus of competing fruit vendors? Apples! Oranges! How dare I compare them when, obviously, they are so different. But here’s the thing. In the United States, researchers have found the prevalence of MS to be nearly identical between Black and white Americans. Why would South Africa be the polar opposite? The reason there likely has nothing to do with the Poles, North or South. Flip back a few pages and you’ll find the answer reaffirmed by Dr. Dean’s research: money. White South Africans earn five times that of Black South Africans, a wealth gap unchanged since Apartheid. Many white South Africans have the disposable income to travel. And they like to travel to Europe. And Europe is home to, drumroll, blacklegged ticks. And they get bitten while visiting. And then return home to South Africa with an unexpected gift: Lyme disease.

For science to be reliable, it has to be repeatable. Dr. Dean and Dr. Kurland suspected an environmental trigger, but ticks as the vector were decades away from discovery, so their theories gradually sunk into muddy unknowns, curious oddities for future researchers to dissect. Enter into evidence Exhibit B: Puerto Rico… and a bushel of apples. Instead of comparing MS rates in the Caribbean territory to far-flung destinations, let’s compare it to its neighbors—apples to apples—focusing on its closest, the Dominican Republic, a mere 205-nautical-mile stone skip to the west and a full degree to the north. According to the latitude gradient hypothesis, the two countries should have near identical patterns of MS.

They don’t. At all. It’s not remotely close.

According to an exhaustive 2017 collaborative study relying on the expertise of each country’s leading neurological association, Puerto Rico isn’t just an outlier in terms of MS cases. It’s Roger Bannister breaking the 4-minute mile, only if he ran it in an incomprehensible 4.94 seconds. There are nearly 50 times more cases of MS per 100,000 in the P.R. than in the D.R. The comparison gets worse if Guatemala and Nicaragua are added to the mix, two countries with even lower rates of MS. The wealthier countries of Panama and Costa Rica buck the trend slightly, but Puerto Rico still bests them both by nearly an order of magnitude. Researchers grappling with this discrepancy spitballed rationalizations that defy plausible rationality.

Sir Roger Bannister winning a race in 1953

Sir Roger Bannister, the first person to break the 4-minute mile, was also an accomplished neurologist who studied POTS (Postural Orthostatic Tachycardia Syndrome), a common symptom of Lyme disease. 1953 (Wikipedia)

The data from this report show that prevalence in most of these countries fluctuates between very low and low with exception of Puerto Rico who has a moderate prevalence. Reasons adjudicated for Puerto Rico’s higher prevalence in the region include the contribution of a national MS registry, unique in the Americas and enforced by local law. In addition, Puerto Rico has a different genetic population make up from the rest of Latin America (higher concentration of white Caucasian groups). Analysis of the origin of its population should eventually be considered.

An MS registry and an influx of pastiness might nudge MS cases slightly upward. I’d even let researchers push past reasonable expectations and run with estimates that double, even triple the caseload. But 50 times?! It’s akin to attributing a record-setting sub-5-second mile to better running shoes and a more aerodynamic haircut. Maybe instead of proposing to “eventually” analyze the origin of Puerto Rico’s population at some future date, researchers had simply focused on where Puerto Ricans living on the island like to travel. They would have discovered that, like most people on Planet Earth, they prefer to visit family. And with more than 50 percent of Puerto Ricans living in the continental US—a percentage that easily dwarfs all other Caribbean nations—it only takes a glance at a census map to see where they reside Stateside. Or, I dunno, a visit to Wikipedia.

The Northeastern United States is home to 2.5 million Puerto Ricans, comprising 53% of the Stateside Puerto Rican population nationwide. Lower New England and the NY-NJ-PA area hold the majority of the region's Puerto Rican population. Combined, the New England states are home to over 600,000 Puerto Ricans, with the vast majority in the Lower portion of New England, having a very high concentration of Puerto Ricans.

United States Census Bureau, Public domain, via Wikimedia Commons

Largest Detailed Hispanic Origin Group by State: 2010.

United States Census Bureau, Public domain, via Wikimedia Commons

The first time I visited Connecticut I came home with a tick and Lyme disease. It seems rather plausible that more than a few Puerto Ricans have shared a similar misfortune. But again, researchers are gonna huff, where is the hard proof? Maybe it’s just coincidence?

Or not.

Something is Wrong

In Puerto Rico, MS prevalence isn’t the only outlier. Everything MS related screams SOMETHING IS VERY WRONG. It’s painfully clear that their disease modifying therapies aren’t working as well as they should be compared to MS norms. Recent research found that “there is a high percentage of Puerto Rican MS patients that are disabled (26.85%). Many of the analyzed individuals require or have required walking aid assistance and many (21.74%) are in a progressive form of the disease. 37.38% of patient had a high EDSS rating, further establishing their rate of disability.” Patients are cresting disability milestones in Puerto Rico more than a full decade faster than expected. Multiple sclerosis isn’t supposed to be so blindingly aggressive and disabling. No way.

Then there’s this. While the average age of MS disease onset should be hovering in the high 20s or low 30s like every other country in the Caribbean and Central America, the Island of Enchantment checks in at a geezerly 41 years of age, nearly a full decade above expectations. As discussed in detail in Chapter 31: Math, neurological forms of Lyme disease tend to be diagnosed far later in life: mid to late 40s. Extrapolating from the vast discrepancy in age of onset alone using the same calculations from that chapter suggests that the majority of people diagnosed with MS living in Puerto Rico are misdiagnosed, upwards of a sky-high 70%.

El Morro in San Juan Puerto Rico
View of El Morro in San Juan, Puerto Rico

That sounds outrageous… because it is. And Puerto Ricans should be outraged. But with the inaccuracy of Lyme disease testing, how can physicians identify those patients? Researchers could, in theory, investigate individual patients, mining everything from their travel history to their DMT failures in order to suss out potential cases of misdiagnosis. But there might be a far, far easier way: basic diagnostic testing.

Researchers might have already solved how to identify Lyme disease within standard, routine lab work already done for MS. They just never realized it. Which leads us, conveniently, to our third twist.


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