How Common are Hookworm Infections in Humans?

Hookworms are tiny parasites named for their hook-like mouths, which they use to grab onto your skin. Once they’re attached, they can burrow into your body and travel to your gut, causing a number of health problems along the way. 

There are two main types of hookworms that infect humans: Ancylostoma duodenale and Necator americanus. Hookworm infections are common worldwide. You’re less likely to get a hookworm infection in the U.S., unless you happen to be in an area where hookworms are very common. 

So, do you need to worry about hookworm infection? It depends on where you live, where you travel, and your pets’ health. 

How common are hookworm infections in humans?

Hookworm infections are common throughout the world. Experts estimate that hundreds of millions of people have hookworm infections. People develop hookworm infections when they come in contact with soil that contains hookworms. 

Indoor plumbing and widespread sanitation measures helped curb what was once a widespread problem in the U.S. Nowadays, it’s rare for people in the U.S. to come in contact with hookworms. Therefore, hookworm infections aren’t common in the U.S. anymore. But cases do happen and sometimes make the national news. And a recent study showed that hookworm infections are still a major concern in certain parts of the southeastern U.S.

In general, you’re unlikely to come in contact with hookworms in the U.S. But you should be aware of hookworms if you’re traveling to parts of the world where hookworm infections are common (including specific parts of the U.S.).

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How do humans get hookworms?

Hookworm infections develop when you come into direct contact with soil or sand that contains young hookworms. Hookworms thrive in moist conditions. So, they’re more common in areas where the ground gets plenty of rain.

The hookworms in the soil bite your skin and then burrow into your body. Hookworms aren’t strong enough to get through shoes or clothes. So, your skin has to come in direct contact with the soil or sand. One common way this happens is when people walk outdoors without shoes. Hookworms bite the soft webs between the toes and use that to get into the body. 

You can also get exposed to hookworms if your hands or other parts of your skin come in direct contact with soil or sand. This can happen while gardening or doing yard work. Children often develop hookworm infections from playing with sand or soil that’s contaminated with hookworms. 

Ancylostoma duodenale can also cause an infection if they’re eaten. The young worms can travel from soil and onto fruits and vegetables. You can accidentally ingest the worms if you eat these foods without first washing them. 

After hookworms get into the body, they travel through the blood vessels to the lung. This triggers people to cough up the worms and then swallow them. The worms then go to the intestines where they develop into mature worms. They can live inside the intestines for more than a year. During this time, they lay eggs. Some of these eggs hatch into immature worms. Immature worms and unhatched eggs pass into the environment through stool. 

In many places, the cycle of infection gets interrupted at this point. In places with indoor plumbing and organized sanitation, wastewater gets treated. This kills parasites and other germs and keeps them out of circulation. 

Can you get hookworm infections from your dog or cat?

Yes, you can get a hookworm infection from your pet. But not directly. 

Hookworms can infect animals the same way they infect humans. 

Animals with hookworm infections poop out hookworm eggs and young worms into the soil. From there, eggs hatch and young worms grow in the soil. These new worms can infect other animals and humans who may come in contact with that soil. 

Animal waste isn’t processed like human waste. So, worms from animal stool can continue to circulate in the environment and cause more infections. 

What do hookworms do in the body?

Hookworms can affect human health in several ways.

Iron-deficiency anemia

Hookworms feed on blood that reaches the intestines. This is a slow but persistent blood loss that can, in turn, cause iron-deficiency anemia. Iron-deficiency anemia can cause a variety of symptoms and impact your overall health if it’s not treated. Iron-deficiency anemia also affects children’s ability to learn. This is the most common way that hookworms harm health. 

Protein deficiency

People with hookworm infections also develop low protein levels in the body. This may be because the body often loses protein when it also loses blood. But it’s possible that the hookworm infection also makes it harder for the gut to absorb protein from food. 

Rashes

Hookworms can cause a rash called cutaneous larva migrans. These are red, itchy lesions that develop on the skin in the spots where the hookworm entered the body. People are more prone to developing bacterial skin infections, like impetigo and cellulitis, in these spots, too.

Cough

People can experience coughing and wheezing when the hookworm passes through the lungs. These symptoms usually go away after the worm leaves the lung and passes into the intestines. 

Eosinophilic enteritis

Eosinophilic enteritis is an inflammatory condition of the small intestine. It can be triggered by hookworm infections. Eosinophilic enteritis can cause abdominal pain, diarrhea, and weight loss. Most people with hookworm infections don’t develop eosinophilic enteritis. 

Eye infections

Hookworms can travel through blood vessels and into the eye. This is uncommon. But it can lead to diffuse unilateral subacute neuroretinitis. This condition can permanently damage vision. Hookworms in the eye can also cause ocular larva migrans. Ocular larva migrans can lead to eye inflammation and damage vision, too.

How do you know if you have hookworms?

Many people with hookworm infections don’t know they have it because they don’t experience any symptoms. 

But the first sign of an infection is usually cutaneous larva migrans — the intensely itchy rash caused by hookworm infection. This rash develops where the hookworm first bit you, usually on the feet. Some people may mistake it for athlete’s foot or ringworm at first. But then the itchy red lines move, and the worm moves along the skin. 

Another sign you might have hookworms is if you unexpectedly develop iron-deficiency anemia. There are many other causes of iron-deficiency anemia. But you can consider hookworm infection if you have iron-deficiency anemia and your pet has a history of hookworm infection or you’ve been in an area where hookworms are common.

Your healthcare team can diagnose you with hookworms by examining a stool sample for eggs or young worms.

How do you treat a hookworm infection?

Hookworm infections don’t always require treatment. Hookworms will die on their own. But you may need treatment if you have bothersome symptoms or if you keep getting hookworm infections.

Hookworm infections can be easily cured with medications like:

• Albendazole

• Ivermectin

• Mebendazole (Emverm)

• Pyrantel pamoate

Only Emverm and pyrantel pamoate are FDA-approved to treat hookworm. Albendazole and ivermectin may be used off-label for hookworm treatment. 

You’ll need to take medication for up to 3 days to cure your infection. 

You may need to take iron supplements for several weeks to correct iron-deficiency anemia from a hookworm infection.

How can you keep from getting hookworms?

Hookworm infections aren’t common in the U.S. Most people don’t need to take special precautions to stay safe from hookworms. But, if you live in an area — or are traveling to an area — where hookworms are common, here’s how you can stay safe:

• Wear shoes whenever you’re outdoors.

• Wash your feet if you’ve been outdoors without shoes.

• Wear gloves if gardening or working with sand or soil.

• Wash your hands and clothes after working outdoors.

• Wash fruits and vegetables before eating them.

• Don’t let children play in areas where animals poop.

It’s also important to keep your pets up to date with their preventative worm medications and routine stool checks. Preventative medication keeps your pet worm-free, so you don’t have to worry about accidentally getting a hookworm infection from them. Regular stool checks allow your vet to diagnose and treat infections quickly.

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Written by:

Shiv Sudhakar, MD

Shiv Sudhakar, MD, is a fellow of the Infectious Disease Society of America and works as a physician in California. He has co-authored over 10 peer-reviewed research articles, published several short stories, had a script recently optioned, and presented 20 scientific presentations, two of which placed in the top 3 at the American College of Physicians.

Edited by:

Patricia Pinto-Garcia, MD, MPH

Patricia Pinto-Garcia, MD, MPH, is a medical editor at GoodRx. She is a licensed, board-certified pediatrician with more than a decade of experience in academic medicine.

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