Hookworm

What is Hookworm?

Hookworms are a type of parasite that often spreads through soil that’s been contaminated. They are most commonly found in tropical and subtropical areas and usually affect individuals who are poor. Two specific kinds of hookworms, known as Ancylostoma duodenale and Necator americanus, are primarily responsible for infections in humans. These parasites can cause long-term infections in your intestines, and they survive by feeding on your blood, which can result in a condition known as iron deficiency anemia. This condition is marked by a lack of red blood cells in your body due to not having enough iron, leaving most people feeling fatigued.

In some cases, these parasites can also cause problems in your lungs as the larvae, or young hookworms, move through your body. There are several medications available to treat hookworm infections. However, preventing these infections in the first place is the best way to avoid any complications associated with them.

What Causes Hookworm?

There are different types of hookworms that can infect humans. The main ones are Ancylostoma duodenale and Necator americanus. There’s also another type of hookworm called Ancylostoma ceylanicum. This one is usually found in some parts of Asia and it’s pretty significant because it can be transferred from animals to humans. However, it usually doesn’t cause blood loss.

Other types of Ancylostoma hookworms usually infect dogs, like Ancylostoma caninum. But, it can sometimes cause inflammation of the gut in humans, specifically the sections called the small intestine and the ileum.

Lastly, there’s a type called Ancylostoma braziliense that’s known for causing a skin condition called cutaneous larva migrans, which is basically where the worm larvae migrate to the skin and cause inflammation.

Risk Factors and Frequency for Hookworm

Close to 470 million people worldwide are infected with hookworms. These infections are most common in developing countries, causing significant economic damage due to anemia which worsens existing poverty and disease.

The main cause of hookworm infections globally is a type called Necator americanus. Another type, Ancylostoma duodenale, is mostly found in the Mediterranean region, and in northern parts of India and China.

Risk factors for getting hookworm infections include:

• Being from a low socioeconomic background
• Exposure to infected soil
• Walking barefoot
• Poor sanitation and personal hygiene

Children and pregnant women are at the greatest risk. The spread of hookworms can be influenced by many factors, including a warm and moist climate, contaminated water, and poor sanitation.

Signs and Symptoms of Hookworm

Hookworm infections often don’t show any symptoms. However, when symptoms do appear, they depend on the stage of the infection and where it is in the body. The infection usually begins when the parasite enters the skin, causing a red, itchy reaction known as ground itch.

There is a type of hookworm infection that affects the skin, known as cutaneous larvae migrans or creeping eruptions. This is common in many developing countries and is often seen in travelers and healthcare workers in developed countries. The infection begins as a red bump that turns into serpentine tunnels under the skin, that range from 1 to 5 cm in size. This is due to the larvae failing to penetrate the deeper layers of the skin and remaining near the surface. This kind of infection typically affects the hands and feet, which are common contact points with soil.

When the infection reaches the lungs, symptoms like a cough, sneezing, bronchitis, coughing up blood, and a particular type of pneumonia known as Loeffler syndrome, may appear. These symptoms usually resolve on their own and do not require treatment. If the infection is consumed orally, you might experience nausea, vomiting, throat irritation, coughing, and shortness of breath, which is known as Wakana syndrome.

When the worms travel to the small intestine, individuals may experience vague abdominal symptoms such as stomach pain and bloating, diarrhea, blood in the stool, and in rare cases, black, tarry stools. Surgery is rarely required due to the small size of the parasites.

The main health problem associated with a hookworm infection is iron deficiency anemia, which results from loss of blood, either directly from the parasite feeding or blood leaking from where the parasite attaches to the gut. Furthermore, people with hookworm infection might experience hypoalbuminemia, which is a low level of albumin in the body and can lead to fluid buildup and swelling. There are also some patients who develop an unusual craving for dirt and may ingest it, a condition known as geophagia.

Testing for Hookworm

Hookworm infections often have unspecific and potentially misleading symptoms. Therefore, understanding the disease’s spread, symptoms, and lab test results can significantly help in pinpointing the right diagnosis.

One common way to identify a hookworm infection is by examining a stool sample under a microscope. This test can not only detect the presence of hookworm eggs but also estimate how many there are. In hospitals, labs usually leverage advanced techniques to concentrate the eggs for a clearer view. For mass screenings and public health control efforts, they might rely on simpler methods like the Kato-Katz technique. However, these techniques may have less accuracy, especially when the infection is not severe. Another test, the IgG4 assay, can potentially identify recent hookworm infections, but it’s not always reliable.

If you have hookworms, your body may respond by increasing its production of a type of white blood cell called eosinophils. This could lead to a condition called eosinophilia, which can be a clue that you might have a hookworm infection. This condition can be detected in your blood even before the hookworms reach your intestines.

Capsule endoscopy, which involves swallowing a tiny camera, might also be capable of spotting adult hookworms in your intestines but is rarely used for diagnosis. Detecting hookworms in images from capsule endoscopy using computer tools is still challenging. The ultimate goal is to develop computer models that can detect hookworms automatically and accurately, even better than experienced endoscopists.

Treatment Options for Hookworm

Hookworm infections are mainly treated using medications called mebendazole and albendazole. Studies suggest that a single dose of 400 mg albendazole is more effective than a single 500 mg dose of mebendazole. Taking three daily doses of either drug back-to-back can lead to better cure rates and help reduce the number of eggs the worms lay. However, this is less practical for large-scale treatment programs. Another option is a three-day treatment with 100 mg of mebendazole taken twice daily, which works well for uncomplicated cases that aren’t severe. Also, a medication called pyrantel pamoate can be taken for three days, which could be another option.

Research looking at many studies together – a meta-analysis – showed that a single dose of oral albendazole was 72% effective against hookworm infections. In comparison, a single dose of mebendazole was 15% effective, and pyrantel pamoate was 31% effective.

How well the medication works can depend on several factors. These include how bad the infection is, where in the world the infection occurred and the age of the person infected. Both mebendazole and albendazole are usually safe to take, with temporary side effects like dizziness, headaches, and stomach upset occasionally happening.

It’s worth noting that pregnant and breastfeeding women who have hookworms are more likely to become anemic. We don’t have a lot of data on whether mebendazole or albendazole are safe to take during pregnancy or while breastfeeding. The World Health Organization says it’s safe for breastfeeding women to take mebendazole, but they should be wary of taking albendazole.

Sometimes, treatment doesn’t work. While we don’t fully understand why, it could be because the worms have become resistant to the medication. Alternative treatments include medications called pyrantel pamoate and levamisole, though they aren’t as effective as albendazole. For skin infections caused by hookworm larvae, oral albendazole or a medication called ivermectin can be effective treatments.

Deworming medication taken together with iron supplements can have a big impact on anemia, especially in people who aren’t getting enough nutrients. A study showed that school children who took multi-nutrient supplements and deworming medication had higher levels of hemoglobin, regardless of their initial hemoglobin levels and nutrition status. Hemoglobin is a protein in your red blood cells that carries oxygen from your lungs to the rest of your body. Anemia is a condition where your body has a lower level of hemoglobin than normal.

For severe cases of anemia, a patient may need a blood transfusion. People who are severely affected might also need nutritional support and should have their response to the treatment monitored frequently.

There’s not enough data to guide the long-term monitoring of treatment. Given that treatment can fail and reinfection can occur, monitoring a patient’s symptoms of anemia and testing their stool is a good idea. Follow-up checks at 1, 4, and 12 months after treatment are likely to be appropriate.

What else can Hookworm be?

If you’re experiencing anemia due to iron deficiency, your doctor will need to rule out other issues tied to your intestines. These could include:

• Malabsorption problems, where your body doesn’t absorb nutrients properly.
• Erosions in your stomach or esophagus.
• Peptic ulcer disease, which is painful sores in your stomach lining.
• Different types of gastrointestinal cancers.

Furthermore, there are other infections caused by worms that can show similar symptoms as a hookworm infection. Your doctor might need to check for:

• Ascariasis, an infection caused by a type of roundworm.
• Schistosomiasis, a disease caused by a type of freshwater parasite.
• Strongyloidiasis, an illness caused by a type of threadworm.

Hookworm infections can also lead to skin symptoms. If these appear, the doctor will want to make sure they aren’t due to other conditions, such as:

• Contact dermatitis, which causes a skin rash when you touch certain substances.
• Migratory myiasis, a condition where fly larvae infect the skin.
• Scabies, an infestation of a tiny bug that burrows into your skin.
• Cercarial dermatitis, a skin rash caused by parasitic worms.

What to expect with Hookworm

Having a hookworm infection tends to cause sickness more than death. In adults, this can lead to anemia (lack of enough healthy red blood cells) and malnourishment, which can decrease the ability to work and ultimately deepen poverty.

During pregnancy, women need more iron, so having a hookworm infection can be riskier, affecting both the mother and the baby’s health. School children with hookworm infection run the risk of cognitive decline and lower academic performance. In contrast, preschool children are less likely to suffer from anemia and malnutrition due to the infection.

There’s been increased worry about treatments, especially after large-scale medication distribution programs, failing to cure hookworm infections. It’s not clear how deworming treatments impact a person’s quality of life. What’s more, there’s a need to create new, more potent medications and to evaluate the effectiveness of using multiple drugs to treat the infection.

Another hurdle in hookworm treatment is reinfection. After treatment, there is a moderate chance of getting reinfected, especially in areas where hookworm infections are common. This supports the idea of giving multiple rounds of medication. One study involving 405 school children revealed that 25% got reinfected with hookworms about 18 weeks after treatment.

Possible Complications When Diagnosed with Hookworm

Complications from adult hookworm infections usually involve a lack of enough iron in the blood, which is called iron deficiency anemia. Rarely, there may also be noticeable bleeding in the digestive tract. Other related complications can include skin and lung conditions.

Common Complications:

• Iron deficiency anemia
• Visible bleeding in the digestive tract
• Cutaneous larvae migrans (skin condition due to the parasites)
• Eosinophilic pneumonia (lung inflammation)

Preventing Hookworm

Mass drug administration campaigns, when large groups of people receive medication, are effective in significantly reducing the number of people who have the infection. However, after stopping the medication, it’s quite common for the infection to return.

One of the best ways to prevent catching the infection is through public health campaigns that promote practices such as proper food sanitation, drinking safe, clean water, washing your hands, and wearing footwear.

A vaccine is currently still being developed and tested. This vaccine is being created specifically to help prevent infections in areas where the infection is extremely common and the impact of the disease is at its worst. The vaccine works by producing antibodies that neutralize, or stop the functioning of, adult worms in the gut. These antibodies also reduce the worm’s ability to consume the host’s (the individual who is infected) blood.

The best way to eliminate the infection, is by reducing poverty and increasing economic development. While these measures have done the most in eliminating the infection, they are obviously not easy tasks to achieve.