Chagas Disease

Chagas disease is an infection caused by the protozoan parasite Trypanosoma cruzi. It is also called American trypanosomiasis. It is mainly seen in the area of Central and South America. Chagas disease can be transferred from mother to child during pregnancy. It mainly transmits by the bite of an infected triatomine bug, commonly known as the "kissing bug" to humans or through contaminated food or drink, blood transfusions, and organ transplant.

Acute and chronic are the two stages of Chagas disease. Many people may not have any symptoms during the acute phase, which lasts for a few weeks to a few months, or they may have moderate symptoms like fever, headache, lethargy, or swelling where the insect bite is. Some people may encounter more serious symptoms including cardiac or digestive issues. The chronic phase of Chagas disease can last for years or even decades, during which the parasite can damage various organs in the body, particularly the heart and digestive system.

Treatment for Chagas disease is available, but it is more effective if started during the acute phase. Preventative measures include using insecticides to control the spread of triatomine bugs, practicing good hygiene, and screening blood and organ donors for the parasite.

Chagas Disease: Causes

The important causes of the Chagas disease include −

  • Humans acquire infection from a bite from an infected triatomine bug, sometimes referred to as the "kissing bug," which is the most common way to acquire Chagas disease. In rural and suburban regions, these insects are frequently present in the cracks and crevices of shoddy-built homes. They defecate after ingesting human or animal blood, and the parasite in their feces can enter the host through bite wounds or other skin breaks.

  • Food or Drink Contamination  The parasite that causes Chagas disease can also be spread by contaminated food or drink. This can happen if food or drink is mistakenly consumed along with the parasite-containing triatomine bug feces.

  • Organ transplants and blood transfusions  Chagas disease can occasionally be spread through these procedures when the donor is infected. Although less common, this method of transmission might be problematic in regions where Chagas disease is an endemic problem.

  • Mother-to-Child Transmission  Pregnant women infected with Chagas disease can transfer the parasite to their babies during childbirth. This is called congenital Chagas disease.

Chagas Disease: Symptoms

The presentation of Chagas disease depends on the stage of infection. Symptoms vary from person to person. Some persons may present with no symptoms whereas some patients present with severe complaints. Chagas disease has two stages: the acute stage and the chronic stage.

Patients with acute stage present with the following symptoms −

  • Fever

  • Fatigue

  • Redness or swelling at the injection site (usually the bite wound)

  • Headache

  • Muscle ache

  • Enlarged spleen or liver

  • Enlarged lymph nodes

In patients with the chronic phase, the symptoms can last for years, and symptoms may worsen over time, they present with −

  • Irregular or palpitations in the heartbeat

  • Having trouble swallowing

  • Discomfort or pain in the abdomen

  • Bloating or diarrhea

  • Reduced appetite

  • Fatigue

  • Inflamed limbs

  • Unexpected weight reduction

  • Injury to the nervous system that causes sensory or motor impairment

  • Changes in behavior or emotion

  • In severe cases, patients may present with heart disease, colon or esophageal damage, and sudden death

Chagas Disease: Risk Factors

The main risk factors of the Chagas disease include −

  • Residing in or visiting regions where the parasite is prevalent  Much of Mexico, Central America, and South America's rural areas are home to the parasite that causes Chagas disease.

  • Sleeping in a home with mud or thatched walls  The parasite-carrying insects prefer to live in the cracks and crevices of shoddy buildings with mud, thatched walls, or adobe construction.

  • Consumption of contaminated food or drink.

  • Organ transplants and blood transfusions  Rarely, organ transplants or blood transfusions from infected donors can spread the Chagas disease.

  • Congenital transmission  After childbirth, a pregnant woman who is infected with the parasite can transmit it to her unborn child.

  • The danger of exposure to insect vectors that transmit certain diseases may increase in certain industries like farming and construction.

Chagas Disease: Diagnosis

The diagnosis of Chagas disease is based on the history, and clinical examination, and, some of the tests may be required to confirm the diagnosis

  • Clinical history and examination  A detailed history of the symptoms, including when they first appeared, as well as any recent travel to or residence in Chagas disease-prone regions should be asked for. physical examination is done to check for any disease-related symptoms.

  • Blood tests  Blood tests are required to diagnose Chagas’s disease. Antibodies to the parasite are looked for.

  • ELISA and IHA Tests  The enzyme-linked immunosorbent assay (ELISA) test and the indirect hemagglutination assay (IHA) test are often done separately. If either of these tests is positive, a Western blot confirmation test is often conducted.

  • Imaging studies  In chronic stages, imaging studies are required to evaluate the extent of organ damage. Electrocardiogram is done to look for abnormalities in the heart functioning.

Chagas Disease: Treatment

Treatment of the Chagas disease depends on the severity of the disease.

  • Chagas disease is commonly treated in its acute stage with antiparasitic drugs. The most often prescribed drugs are benznidazole and nifurtimox. These drugs help to remove the parasite from the body and stop the disease's progression to the chronic stage.

  • The management of the disease's symptoms and sequelae is the main goal of treatment for the chronic stage of Chagas disease. In some patients, surgery may be necessary to repair damage to the digestive system, drugs may be used to treat heart failure or arrhythmias.

Chagas Disease: Prevention

Prevention of the Chagas disease can be done by following the methods listed below −

  • Avoid traveling the places where the Chagas disease is more prevalent.

  • Avoid sleeping in shoddy homes with thatched walls, mud, or adobe to reduce the risk of exposure.

  • Insecticides can be used to kill insects, and bed nets can act as a physical barrier between people and insects.

  • Reducing exposure to insect vectors can be achieved by improving dwelling conditions. Make sure that doors and windows are well sealed, as well as repair or replace thatched roofs, walls, and floors.

  • Avoid ingesting contaminated foods or drinks.


Chagas disease is an infection caused by the parasite Trypanosoma cruzi. The disease is more common in some areas. An individual gets infected by the bite of the parasite, through contaminated water and food, and rarely through blood and organ transfusion.

The patient may present with no symptoms in the beginning. Symptoms vary from person to person. The patient can present either with acute or chronic stages.

Diagnosis is based on the symptoms, clinical presentation, and blood tests to look for antibodies to the parasite, ELISA and IHA are done, and if either of them is positive then should be confirmed by western blot. Imaging studies are done in severe cases to look for the involvement of the other organs.

The disease is treated with an anti-parasitic drug in the acute stage. In the chronic stage, the treatment mainly aims at preventing complications. Treatment is more effective if started during the acute phase. Preventative measures include using insecticides to control the spread of triatomine bugs, practicing good hygiene, and screening blood and organ donors for the parasite.

Dr. Durgesh Kumar Sinha
Dr. Durgesh Kumar Sinha


Updated on: 14-Jul-2023


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