River blindness, also known as onchocerciasis, begins with a simple fly bite but leads to a lifetime of suffering. This condition is caused by a parasite called Onchocerca volvulus that enters the human body to survive. Its larvae migrate through the body, causing intense itching and eventually leading to blindness.

Imagine that you are a worm, a very specific kind of worm. Uncle Serka volvulus. Your goal in life, your mission, your only purpose, is to worm your way into the human body. You are a parasite. You need the human body to survive and to thrive.

For centuries, there was no effective way to prevent this blindness. Now, a medication called ivermectin provides a solution. Taking one small tablet once or twice a year stops the transmission of the parasite and protects entire communities. This allows a new generation to grow up free from the threat of the disease.

This pill, ivermectin, makes life very difficult for a parasite.

Ivermectin is a highly effective medicine used to kill parasites that cause diseases such as river blindness and elephantiasis. These tropical diseases mostly occur in Africa, South America, and parts of Asia. The drug is also effective against hookworm and is commonly used in veterinary medicine to treat heartworm in pets and livestock.

I think that it's probably not a bad idea to use it once or twice a year to cleanse out of your body. Some of my patients will take ivermectin as a prevention for viral illnesses. Totally fine, totally safe.

In recent years, the drug has gained new attention on social media platforms like YouTube. Many people now discuss ivermectin as a potential treatment for viral illnesses like Covid or even cancer. While it is a celebrated tool for fighting parasites, its use for these other conditions is based on emerging claims and literature that people are now beginning to explore.

A parasite is an organism that lives on or inside another creature and feeds off it. This category includes common pests like ticks and lice, but also more bizarre species like the tongue-eating louse. This crustacean enters a fish through the gills and eventually replaces the fish's tongue. It stays in the mouth and eats a portion of the food the fish consumes. Parasites have affected humans for as long as our species has existed. Over the last 600 years, migration and slavery helped spread various parasitic diseases across the globe. Even the U.S. Centers for Disease Control and Prevention was established in Atlanta because parasitic diseases like malaria and hookworm were once common in the American South.

It lives there in the mouth, helping the fish eat, just as a tongue would, but taking a nibble of food every now and again. That, my friends, is a parasite.

In the early 1900s, zoologist Charles Stiles investigated why so many people in the South suffered from anemia and stunted growth. By studying stool samples, he discovered that hookworms infected nearly 40 percent of the population. These parasites thrive in areas with poor sanitation where people walk barefoot. The larvae burrow through the skin of the feet and travel through the bloodstream to the lungs. After being coughed up and swallowed, they settle in the small intestine. There, they latch onto the intestinal wall and feed on human blood.

This blood loss causes severe iron deficiency and extreme fatigue. When Stiles announced his findings, the press labeled the hookworm the germ of laziness. This discovery provided a medical explanation for common stereotypes about the slow pace of life in the South. Despite the high infection rates, the problem was largely ignored by the government. This was mainly because the disease primarily affected the very poor and Black communities during the Jim Crow era.

Stiles noted that there might be a connection between this hookworm, the American killer, and the characteristic state of southern lassitude. And that became front page news. The headline in the New York Sun screamed germ of laziness found.

Stiles advocated for a simple solution to public health issues: clean up. He saw the habits of daily life as the primary cause of preventable sickness. In 1908, he joined forces with advisors to John D. Rockefeller. Together, they formed the Rockefeller Sanitary Commission to fight hookworm in the southern United States. This group later evolved into the Rockefeller Foundation. They identified three main ways to stop the disease. First, they used a chemical called thymol to purge the worms from the body. It was a difficult treatment that caused illness, but it worked quickly.

In our filthy American habits of daily life, I see the cause of more preventable sickness and preventable death than I do in any other one factor.

The second strategy focused on sanitation. Many homes in the South had no toilets at all. The commission started a campaign to build outhouses with deep pits for every household. Third, they encouraged people to wear shoes. Children often went barefoot in the summer, which made them easy targets for the worms. These efforts were successful and led to better state health departments. However, the movement faced pushback. Critics formed the National League of Medical Freedom. They were funded by practitioners of alternative medicine who did not want the government telling people which treatments to use. They called mainstream medicine the medical octopus. Even as medical science improved in the 1930s, the debate over medical freedom continued.

Hookworm was mostly gone from the southern United States by the 1950s, but it remains a global issue. In many parts of sub Saharan Africa, communities face the threat of river blindness. People depend on rivers for water and work, but these locations are also home to the black fly. These flies transmit worm larvae that breed under the skin. While the adult worms do not trigger a strong immune response, the baby worms can move into the eyes. This causes intense inflammation that leads to permanent vision loss.

The water from the rivers is precious indeed, but the rivers are treacherous. They produce the black fly that brings blindness.

River blindness rarely kills an individual, but it can destroy a whole community. It often strikes people during their most productive years. This forces children to drop out of school or leave the workforce to care for blind parents. Over time, families struggle to survive and young people eventually flee the village. Early attempts to control the disease involved using dangerous chemicals like DDT to kill fly populations, but a safer drug treatment appeared in the early 1980s.

The story of ivermectin begins on a golf course in Japan in 1973. A young scientist named Satoshi Omura collected a soil sample there, knowing that dirt is often a battleground for microbes producing chemical agents to survive. At the time, Omura was collaborating with the pharmaceutical company Merck. Out of 40,000 cultures isolated in his lab, exactly one showed a promising antiparasitic effect. This single sample was sent to Merck researchers in New Jersey, where a team led by William Campbell developed it into a powerful drug that consistently killed parasites in livestock.

The sample from that golf course was just one of 40,000 cultures isolated in Omura's lab. The promising ones were then sent overseas to New Jersey, and exactly one turned out to have an antiparasitic effect. It killed worms.

Ivermectin was first approved for veterinary use in 1981, targeting mites, ticks, and various worms in animals. However, parasites remained a devastating issue for humans in developing nations. Merck began testing the drug in Senegal to treat river blindness. When the trials proved successful, the company made a landmark decision to donate the drug for free to as many people as needed for as long as needed. This humanitarian effort allowed entire communities to return to lands once abandoned due to infestation.

The drug's impact expanded in the 1990s when it was found effective against lymphatic filariasis, a disease caused by mosquito-borne worms that leads to elephantiasis. While Merck earned billions through veterinary sales, its commitment to donating the human version changed millions of lives. In 2015, the significance of this discovery was officially recognized when Satoshi Omura and William Campbell were awarded the Nobel Prize in Medicine.

Forty years after these triumphs, we now know that ivermectin works against a great many parasites. And it is easy to take just one or two pills a year. It gives countries a fighting chance to push back on disease and to reclaim land that has been abandoned due to infestation.

The story of the drug took a significant turn in late 2019 with the emergence of a new pneumonia-like virus. Initially detected in China, the virus quickly spread to other countries. The Centers for Disease Control and Prevention confirmed the first United States case in Washington State, signaling the start of a major public health crisis. This situation was described as unprecedented because the virus did not discriminate and affected everyone.

In late 2019, a new disease emerged, Covid. And suddenly ivermectin was front page news.

The health crisis quickly escalated into a global pandemic. Official declarations of public health emergencies and national emergencies followed. Travel was suspended from Europe and everyday life changed as people faced crowded conditions and long waits. The pandemic moved ivermectin into the spotlight, making it a central part of the public conversation.

Repurposing involves using a medicine developed for one purpose to treat a different disease. Viagra is a famous example. It started as a blood pressure medicine but was eventually repurposed for erectile dysfunction. In the early days of the COVID-19 pandemic, people were desperate for treatments. This led to chaotic behavior. Some people suggested using bleach or UV light. Others turned to supplements like Vitamin C, zinc, and elderberry. People rushed to stores to buy anything that might help the immune system.

You put enough of anything in a petri dish in a high enough concentration, it will start inhibiting just cells and kill cells. When I did the back of the envelope calculation, it was like 100 times higher level than you would ever achieve in the human body.

Ivermectin became a focus after a study showed it had antiviral effects in a petri dish. However, David notes that the concentration needed to kill the virus was 100 times higher than what the human body can safely handle. At that dose, the drug would likely be toxic to the patient. Many things work in a lab setting or in mice that do not work in humans. Clinical trials are the only way to test if there is an actual benefit.

Fake data further complicated the situation. A company called Surgisphere published records claiming ivermectin significantly lowered death rates. This data turned out to be completely fabricated. Despite this, the misinformation spread quickly through headlines and political hearings. These papers were cited thousands of times by other researchers. The damage was done before the fraud was fully exposed.

Actual clinical trials eventually provided clear answers. David participated in large studies called Activ6 that tested ivermectin against placebos. These trials involved thousands of people. They looked at whether patients could get better faster or avoid the hospital. The results showed no statistical benefit whatsoever. Multiple trials confirmed that ivermectin was not a viable treatment option for the virus.

There were three trials I was involved with over 1,000 people per trial and basically no statistical benefit over placebo. And you can't be like, oh, you just need more people because there was no benefits whatsoever.

Medical trials for certain treatments showed no benefit even when researchers increased the dosage or the duration of the study. After multiple trials fail to show results, most physicians move on to find what actually works. However, some people remain committed to specific drugs long after the data suggests they should stop. This happens because people often have a vested interest or an emotional attachment to a specific treatment.

The discrepancy between scientific data and personal experience often comes down to the placebo effect. In trials where patients knew they were receiving a treatment, called open label studies, they reported feeling better. This was not the case in placebo controlled trials. The psychological impact of taking a treatment is powerful. It is a real effect, but it is not caused by the medicine itself.

In the real world, this is how people were taking medicines. They saw the label, they took a dose, and a lot of them felt better. It is a real effect. It is just not the medicine.

In cases where most people eventually recover on their own, it is easy to credit the medicine for the recovery. Even if a drug has no actual benefit, patients who take it often feel they improved faster than if they had taken nothing at all. This explains why some treatments remain popular despite a lack of clinical evidence.

Simone managed a supplement department at a grocery store and felt she needed ivermectin when she caught Covid. After taking a single pill, her intense body pain improved by 80 percent within hours. This experience made her a firm believer in the treatment. Her story illustrates the difficult gap between personal experience and scientific evidence. When someone feels better after a treatment, they have a powerful reason to trust it. However, individual anecdotes do not always align with broader data. This tension became a central conflict during the global health crisis.

She had Covid, she took ivermectin, and she got better. She believes ivermectin worked for her, and she has reason to. As Dr. Bulwer explained, sometimes it just works that way. But there is a difference between experience and evidence.

The pandemic damaged the trust between citizens and the government. It also broke the bond between the public and scientific institutions. In early 2021, Merck, the company that discovered ivermectin, announced that its researchers found no meaningful evidence that the drug helped Covid patients. Organizations like the American Medical Association also opposed its use outside of clinical trials. For people who already doubted the medical establishment, these warnings felt like attacks on their medical freedom. This distrust remains high years later. Public figures like Mel Gibson and Joe Rogan continue to discuss the benefits of substances like ivermectin and methylene blue for various conditions. These conversations reach millions of people and reinforce the idea that many effective treatments are being overlooked for profit.

There is currently no evidence that ivermectin serves as a therapeutic for human cancers. While researchers have studied its effects on ovarian, liver, breast, and lung cancers, most of this work stays confined to petri dishes. These findings rarely translate to humans because the amount of a drug needed to kill cancer in a lab setting might also be lethal to a person. Large scale randomized controlled trials remain nonexistent despite popular claims.

The landscape of medical research is shifting toward public demand rather than strictly scientific merit. The National Institutes of Health now feels an obligation to study treatments simply because many people believe in them. This change aligns with a broader movement to make America healthy again. In Florida, the state has even allocated sixty million dollars to a cancer innovation fund to study ivermectin.

If lots of people believe it and it is moving public health, we at NIH have an obligation to treat it seriously. Well, that is not actually the way it is supposed to work. Just because people believe something does not mean it is worthy of studying or that it is worth our money to do the research.

When science shifts to accommodate popular hypotheses, it can create a cycle of anecdotes. Even if a drug fails a trial, participants often experience placebo effects. These individual stories usually carry more weight for the public than complex statistics or p-values. In several states, ivermectin is now available over the counter under the banner of medical freedom. This trend often overlaps with the supplement industry, where unproven treatments are sold to people in desperate situations. Scientists are not trying to hide cures when they say something does not work. They are trying to save patients from wasting money and hope. Hope is a precious resource, and it is easily exploited during desperate times.