We Never Eradicated Parasites—We Just Stopped Looking

We like to believe we conquered parasites — that we left those threats behind with cholera, smallpox, and outhouses. But here's the truth: we never eradicated them. Not in the United States, not in Europe, not anywhere on Earth.

We can't even eradicate lice. Or scabies. Or bed bugs. Or pinworm.

So how could we possibly have eradicated anything more complex or dangerous?

The illusion of eradication is one of the greatest public-health myths of modern times — a myth that makes us comfortable, compliant, and blind to what's happening right under our skin.

1. Everyday Parasites: The Proof We Ignore

If we can't eliminate simple ectoparasites that live on the surface of the body, how could we have conquered the ones that hide inside it?

Every year, millions of U.S. schoolchildren are sent home with lice infestations. Hospitals experience recurring outbreaks of scabies, sometimes spreading between staff and patients. Pinworm infections — caused by Enterobius vermicularis — remain the most common parasitic infection in North America, particularly in children. Bed bugs, once considered relics of the 1940s, have returned with near-complete pesticide resistance.

These are not tropical diseases. They are right here — in our homes, hotels, and hospitals — thriving in climate-controlled environments with endless hosts.

So what does that say about the supposedly "eradicated" ones?

2. The Geography Myth: Climate Doesn't Respect Borders

The southern United States shares the same climate, soil composition, and wildlife as northern Mexico and Central America. Wherever environmental conditions support parasitic lifecycles, those parasites persist—regardless of which side of a political boundary they occupy.

Toxocara and Strongyloides thrive in soil contaminated by animal waste.

Giardia , Entamoeba , and Ascaris flourish wherever sanitation is imperfect.

Ticks, mosquitoes, and flies carry parasites across borders every hour of every day.

A fly does not present a passport.

A mosquito does not stand in line at immigration.

A tick doesn't care which side of the fence it bites on.

The ecological reality is simple: wherever the environment supports a parasite, the parasite will persist. Ecology doesn't care about nationality. Neither do parasites.

So when health agencies speak as if parasites "don't exist here," what they really mean is we stopped tracking them here.

3. Global Travel: Seventy Thousand Daily Gateways

Roughly 70,000 international visitors enter the United States every day. That's over 25 million people a year — many from regions where parasitic infections are common, chronic, and rarely treated.

And here's what no one discusses: infections don't disappear at customs.

Airports have customs lines, not quarantine zones. There is no screening for Strongyloides , Schistosoma , or intestinal helminths — infections that can persist silently for years. A single infected individual can shed eggs or larvae capable of spreading through wastewater, food handling, or vector bites.

Modern medicine may have antibiotics and MRIs, but parasites have evolution on their side. They have existed for hundreds of millions of years, adapting to every climate, every species, and every defense we throw at them. They don't recognize political borders. They recognize opportunity.

4. The Diagnostic Blind Spot

Why don't we see parasites? Because we're not trained — or incentivized — to look for them.

Fifty years ago, parasitology was a cornerstone of medical education. Today, it's a forgotten elective. Most physicians will never order a comprehensive stool analysis in their entire career. Even when they do, traditional ova and parasite (O&P) exams can miss the majority of infections due to intermittent shedding, limited sample collection, and detection methods designed for acute tropical infections rather than chronic low-level infestations.

Meanwhile, parasitic symptoms masquerade as "autoimmune," "neurological," or "psychiatric" disorders. When parasitic infections are misdiagnosed as autoimmune or psychiatric conditions, patients receive symptom management instead of curative treatment—keeping them in the medical system indefinitely.

5. The Cost of Denial

This denial carries a price.

Communities near ecological transition zones experience chronic parasitic infections that are dismissed as "developing world" issues. Urban homeless populations suffer recurrent scabies and lice outbreaks that public health departments label as hygiene failures, not systemic neglect. Immunocompromised patients harbor latent parasites that reactivate under stress or treatment — often misdiagnosed as autoimmune flares.

Suburban families adopt rescue dogs that test positive for Giardia or roundworms. Children play in public parks where wildlife defecates. Adults travel internationally and return with unexplained GI issues dismissed as "IBS." Yet we imagine parasites only affect "other people" in "other places."

Even pets routinely test positive for Giardia , Toxocara , and Dirofilaria (heartworm). Yet somehow we imagine their human companions exist in sterile bubbles.

If parasites surround us in the environment, infest our pets, and afflict our most vulnerable populations, what logic says they spare the rest of us?

6. The Real Parasite Is Complacency

We celebrate "eradication" as a victory of civilization — but what we've really eradicated is curiosity.

We no longer ask the uncomfortable questions. We no longer examine the hidden causes.

And so the cycle continues — invisible, ignored, and profitable.

Until we confront that truth — and restore honest parasitology to medicine, research, and public awareness — the illusion of eradication will remain our most dangerous infection of all.

The implications are vast. If parasites persist and medicine stopped looking for them, how many conditions are actually parasitic? Our comprehensive list documents over 220 conditions likely caused by parasitic infections—from neurological diseases to mental health diagnoses to autoimmune disorders.