Definition

Hookworms are parasitic infections that require a host for reproduction. In the human body, hookworms can cause symptoms in the lungs, skin, and small intestine. Humans become infected with hookworm larvae found in fecally contaminated soil or environments.

According to the CDC, hookworm infections affect 576 to 740 million people worldwide. Due to inadequate sanitation practices, this infection is particularly prevalent in developing countries and regions with tropical or subtropical climates.

Causes

Two types of hookworms, Necator americanus and Ancylostoma duodenale, can infect humans. The eggs of these hookworms develop in the soil after being excreted in human feces. Once in the soil, the eggs hatch until they can infect humans by penetrating the skin.

Individuals can become infected when exposed to soil containing hookworm larvae. The larvae penetrate the skin and enter the bloodstream, eventually reaching the lungs. From there, the larvae enter the upper respiratory tract, and if a person coughs, the parasite is ingested into the digestive tract. The larvae then mature and reside in the small intestine for a year before being passed out with feces.

Indirect transmission can occur if pets are infected. The eggs are expelled in the pets' feces and hatch into larvae, found in the soil where the pets defecate. Humans can become infected by touching contaminated stool with bare hands or feet.

To reduce the risk of infection, it is important to ensure that pets are vaccinated and receive regular deworming medication from veterinarians. Additionally, avoiding walking barefoot in areas where pets commonly defecate is crucial, as individuals may be exposed to contaminated feces with unknown health conditions, especially in gardens.

Risk factor

The risk factors for hookworm infection include:

• Living in environments with poor sanitation.
• Living in areas with limited access to clean water.
• Populations with low income and education levels.
• International tourists and refugees.
• Small children who come into contact with soil or sand.
• Regions with a warm climate. Hookworms thrive in warm and humid soil. The optimal temperature for worm eggs is around 20-30°C, although A. duodenale prefers a lower temperature than N. americanus. Larvae fail to develop at temperatures below 13°C. Eggs that have hatched and new larvae will die below 6-8°C and above 45°C. Eggs and larvae also perish due to drying and direct sunlight.
• Keeping pets, especially puppies and kittens.

Symptoms

Initially, hookworm infections may not present symptoms, especially if the parasite count is low, individuals frequently consume iron-rich foods, or have a healthy immune system. However, in cases of high parasite burden or compromised immunity, the following symptoms may manifest:

• Itching and small rashes on the skin: These occur due to an allergic reaction in the area where the larvae enter the skin.
• Diarrhea
• Abdominal pain
• Abdominal cramps
• Excessive crying in infants
• Nausea
• Fever
• Bloody stools
• Decreased appetite

Diagnosis

In the diagnostic process for hookworm infection, a medical interview is typically conducted to gather information about risk factors and travel history. Following this, a physical examination is performed. If symptoms indicative of hookworm infection are present, the doctor may recommend the following examinations:

• Fecal Examination: A feces sample is examined under a microscope to detect the presence of hookworm eggs. This is a direct method of confirming the infection.
• Blood Examination: A complete blood count (CBC) may be conducted, revealing an increased count of eosinophil white blood cells. Eosinophilia serves as a marker for allergies and worm infections. Elevated eosinophil levels can be observed several weeks before hookworm eggs appear in the feces.

Management

The treatment of hookworm infection aims to achieve several key goals:

• Removal of the worm parasite: The primary objective is to eliminate the hookworm parasite from the body. Medications such as albendazole and mebendazole are commonly prescribed by doctors for a single-dose treatment to address the infection.
• Nutritional rehabilitation: Since hookworm infection can lead to malnutrition, doctors work on helping individuals recover from this condition. Nutritional support may include dietary recommendations and, in cases of suspected complications, adding protein supplements to the diet.
• Management of anemia complications: Anemia is a common complication of hookworm infection due to blood loss. To address this, doctors may recommend iron supplements to help replenish iron levels and alleviate anemia.

Complications

Intense exposure to hookworm infection can lead to severe parasitic manifestations, causing various health complications:

• Digestive tract bleeding: Although rare, infections with Ancylostoma duodenale, particularly in neonates transmitted through breastfeeding, can lead to severe bleeding in the digestive tract.
• Anemia: The hookworms absorb blood from the host, decreasing red blood cell count. Anemia can be more pronounced in individuals with poor diets, pregnant women, or those with malaria.
• Heart failure: Severe cases of hookworm infection can lead to heart failure.
• Malnutrition, growth, and developmental delay: Children infected with hookworms and experiencing anemia are at a significantly higher risk of growth delay. They are also more prone to weight loss than children without such infections.
• Accumulation of fluid in the abdomen (Ascites): Massive protein loss due to hookworm infection can result in fluid accumulation in the abdominal cavity.
• Lowered productivity and cognitive impairment: Anemia, chronic iron deficiency, and protein depletion associated with hookworm infection can reduce productivity and impair cognitive function over time.

Prevention

You can reduce the risk of hookworm infection by:

• Wear shoes when you are outside, especially in areas with animal feces on the ground.
• Drinking clean water.
• Cleaning and cooking food thoroughly.
• Washing hands properly, especially before meals and after using the toilet.
• Improving sanitation in areas prone to hookworm infections. Sanitation improvements include implementing proper waste disposal systems.

Some developing countries provide preventive medication to groups at high risk of infection, such as:

• Children
• Females in their productive age
• Pregnant women
• Breastfeeding women
• People at risk due to their occupation

When to see a doctor?

You should consult a doctor if you experience:

• Itchy rash on the feet
• Unexplained weight loss
• Loss of appetite
• Fatigue or dizziness

Looking for more information about other diseases? Click here!