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Salem Health: Infectious Diseases & Conditions, 2nd Edition

Chagas’ disease

by Anita P. Kuan, , Ph.D.

Category: Diseases and conditions

Anatomy or system affected: All

Also known as: American trypanosomiasis

Definition

Chagas’ disease is a parasitic disease caused by the protozoa Trypanosoma cruzi (T. cruzi). It is typically spread by the blood-sucking insect Triatominae , a subfamily of Reduviidae. It can also be spread through blood transfusion, organ transplant, contaminated food, laboratory exposure, and from a pregnant woman to her baby (congenital transmission).

Of the estimated 8 million cases worldwide, 326,000–347,000 diagnoses were in the United States. Although the triatomine bug survives in the southern United States, the majority of Chagas’ disease cases in the United States are among immigrants from Latin America. Additionally, cases of infection have been reported among travelers returning from Latin America. However, cases of domestically acquired T. cruzi infection in the southern United States have recently been documented, indicating these states could be a focal point for endemic disease transmission in the United States.

Causes

Chagas’ disease is caused by the parasite T. cruzi. Triatomine insects, also known as kissing bugs or vampire bugs because they typically bite a person’s face, become infected by T. cruzi when they ingest blood from animals already infected with T. cruzi. These insects live in the walls of thatch, adobe, and mud houses, emerging at night to feed. After feeding, the bugs defecate. Their feces contain T. cruzi parasites, which can then enter the body through the person’s eyes, mouth, a cut or scratch, or the wound from the bug's bite.

After receiving an insect bite, this child is suffering from Chagas’ disease. Due to the bite, the right eye is swollen. Image courtesy of the CDC. Photo by Dr. Mae Melvin via Wikimedia Commons.

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Risk Factors

Chagas’ disease can affect anyone. Risk factors include living in homes that have triatomine bugs; living in rural areas of Latin America; and receiving a blood transfusion or organ transplant from an infected person.

Symptoms

Chagas’ disease can cause acute (lasting weeks or months) and chronic (occurring ten or twenty years after infection) illnesses. Many people do not experience symptoms until the chronic phase. When symptoms do appear during the acute phase, they are usually mild and may include a swollen bug bite, fever, fatigue, rash, body aches, headache, loss of appetite, nausea, vomiting, diarrhea, swollen glands, enlargement of the liver or spleen, and swelling of the eye nearest the bug bite. Though rare, acute Chagas’ disease can be fatal due to inflammation of the heart or brain.

Chronic Chagas’ disease can damage the muscular walls of the heart and the gastrointestinal tract. This can cause irregular heartbeat, congestive heart failure, sudden cardiac arrest, enlarged heart, weight loss, constipation, abdominal pain, and difficulty swallowing. Some people develop pain or numbness in their hands or feet, encephalopathy, stroke, motor deficits, dementia, and confusion.

Screening and Diagnosis

Most countries screen blood donors and organ transplant donors for Chagas’ disease. Acute Chagas’ disease is diagnosed by blood tests that demonstrate the presence of T. cruzi. To determine chronic disease, an electrocardiogram, an echocardiogram, a chest X-ray, an abdominal X-ray, and endoscopy of the esophagus may be performed.

Treatment and Therapy

Treatment of acute Chagas’ disease is focused on killing the parasite. The antiparasitic medications used to treat Chagas’ disease are benznidazole and nifurtimox.

Treatment of chronic Chagas’ disease focuses on managing signs and symptoms of the disease. Heart problems are treated with cardiac medications or a pacemaker. Gastrointestinal tract problems are treated with diet change, medication, and, surgery.

Prevention and Outcomes

Prevention strategies in endemic areas focus on avoiding bug bites, e.g., using insecticide sprays; insect repellent; not sleeping in mud, thatch, or adobe houses; and by using a sleeping net. Other control strategies are focused on preventing transmission from blood transfusion, organ transplantation, and mother-to-baby.

Antiparasitic medications produce high cure rates for acute and early chronic cases of disease and can improve clinical outcomes in chronic cases. Treatment should be offered as soon as possible, before serious heart disease develops.

Further Reading

1 

Meymandi, Sheba, et al. “Treatment of Chagas Disease in the United States” Curr Treat Options Infect Dis (2018) 10:373–388. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6132494/

2 

Webber, Bryant J., et al. “Prevalence and Seroprevalence of Trypanosoma cruzi Infection in a Military Population in Texas” Am J Trop Med Hyg (2017) Nov 8; 97(5):1477–1481. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5817750/

3 

Gunter, Sarah M., et al. “Likely Autochthonous Transmission of Trypanosoma cruzi to Humans, South Central Texas, USA” Emerging Infectious Diseases (2017) 23, no. 3. Available at https://wwwnc.cdc.gov/eid/article/23/3/16-1157_article

4 

Buckner, Frederick S., et al. “Chagas’ Disease” In: Travel and Tropical Medicine Manual, eds. Sanford, C.A., et al. 5th ed. Philadelphia: Elsevier, 2017.

5 

Estani, S. S. and Segura, E. L. “Protozoan Diseases: Chagas’ Disease” In: International Encyclopedia of Public Health, ed. Quah, S. 2nd ed. Elsevier Science & Technology, 2017.

6 

Manne-Goehler, J et al. “Estimating the Burden of Chagas Disease in the United States” PLoS Negl Trop Dis (2016) 10(11): e0005033. Available at https://doi.org/10.1371/journal.pntd.0005033

Web Sites of Interest

American Society of Tropical Medicine and Hygiene

http://www.astmh.org

Centers for Disease Control and Prevention

http://www.cdc.gov/parasites

Emerging and Reemerging Infectious Diseases Resource Center

http://www.medscape.com/resource/infections

See also: Antiparasitic drugs: Types; Children and infectious disease; Developing countries and infectious disease; Emerging and reemerging infectious diseases; Encephalitis; Fleas and infectious disease; Flies and infectious disease; Insect-borne illness and disease; Insecticides and topical repellants; Intestinal and stomach infections; Myocarditis; Parasitic diseases; Parasitology; Tropical medicine; Trypanosoma; Trypanosomiasis; Vectors and vector control.

Citation Types

Type
Format
MLA 9th
Kuan, Anita P. "Chagas’ Disease." Salem Health: Infectious Diseases & Conditions, 2nd Edition, edited by H. Bradford Hawley, Salem Press, 2020. Salem Online, online.salempress.com/articleDetails.do?articleName=Infect2e_0114.
APA 7th
Kuan, A. P. (2020). Chagas’ disease. In H. B. Hawley (Ed.), Salem Health: Infectious Diseases & Conditions, 2nd Edition. Salem Press. online.salempress.com.
CMOS 17th
Kuan, Anita P. "Chagas’ Disease." Edited by H. Bradford Hawley. Salem Health: Infectious Diseases & Conditions, 2nd Edition. Hackensack: Salem Press, 2020. Accessed September 16, 2025. online.salempress.com.