Chagas Disease (Trypanosoma cruzi infection)

Chagas disease is named after the Brazilian physician Carlos Chagas, who discovered the disease in 1909. It is caused by the parasite Trypanosoma cruzi, which is transmitted to animals and people by insect vectors that are found only in the Americas (mainly, in rural areas of Latin America where poverty is widespread). Chagas disease (T. cruzi infection) is also referred to as American trypanosomiasis.

The diagnosis of Chagas disease can be made by observation of the parasite in a blood smear by microscopic examination. A thick and thin blood smear are made and stained for visualization of parasites. However, a blood smear works well only in the acute phase of infection when parasites are seen circulating in blood.

Diagnosis of chronic Chagas disease is made after consideration of the patient's clinical findings, as well as by the likelihood of being infected, such as having lived in an endemic country. Diagnosis is generally made by testing with at least two different serologic tests.

Treatment for Chagas disease is recommended for all people diagnosed with an acute infection, congenital infection, and for those with suppressed immune systems. Other chronically infected people (especially children) may benefit from treatment.

For cardiac or gastrointestinal problems resulting from Chagas disease, symptomatic treatment may be helpful. Patients should consult with their primary health care provider. Some patients may be referred to a specialist, such as a cardiologist, gastroenterologist, or infectious disease specialist.

In the U.S., medication for Chagas is only available through CDC. Your health care provider can talk with CDC staff about whether and how you should be treated. For questions regarding treatment, physicians can contact the Division of Parasitic Diseases at 770-488-7775.

Introduction

Chagas disease is named after the Brazilian physician Carlos Chagas, who discovered it in 1909. It is caused by the parasite Trypanosoma cruzi, which is transmitted to animals and people by insect vectors that are found only in the Americas (mainly, in rural areas of Latin America where poverty is widespread). Chagas disease (T. cruzi infection) is also referred to as American trypanosomiasis.

It is estimated that as many as 8 to 11 million people in Mexico, Central America, and South America have Chagas disease, most of whom do not know they are infected. If unrecognized and untreated, even silent infection is lifelong and can be life threatening.

The impact of Chagas disease is not limited to the rural areas in Latin America in which vectorborne transmission occurs. Large-scale population movements from rural to urban areas of Latin America and to other regions of the world have increased the geographic distribution and changed the epidemiology of Chagas disease. In the United States and in other regions where Chagas disease is now found but is not endemic, control strategies should focus on preventing transmission from blood transfusion, organ transplantation, and mother-to-baby (congenital transmission).

How do people get Chagas disease?

People can become infected in various ways. In Chagas-endemic areas, the main way is through vectorborne transmission. The insect vectors are called triatomine bugs. These blood-sucking bugs get infected by biting an infected animal or person. Once infected, the bugs pass T. cruzi parasites in their feces. The bugs are found in houses made from materials such as mud, adobe, straw, and palm thatch. During the day, the bugs hide in crevices in the walls and roofs. During the night, when the inhabitants are sleeping, the bugs emerge. Because they tend to feed on people's faces, triatomine bugs are also known as "kissing bugs." After they bite and ingest blood, they defecate on the person. The person can become infected if T. cruzi parasites in the bug feces enter the body through mucous membranes or breaks in the skin. The unsuspecting, sleeping person may accidentally scratch or rub the feces into the bite wound, eyes, or mouth.

People also can become infected through:

• consumption of uncooked food contaminated with feces from infected bugs;
• congenital transmission (from a pregnant woman to her baby);
• blood transfusion;
• organ transplantation; and
• accidental laboratory exposure.

It is generally considered safe to breastfeed even if the mother has Chagas disease. However, if the mother has cracked nipples or blood in the breast milk, she should pump and discard the milk until the nipples heal and the bleeding resolves.

Chagas disease is not transmitted from person-to-person like a cold or the flu or through casual contact.

If I have Chagas disease, should my family members be tested for the infection?

Possibly. They should be tested if they:

• could have become infected the same way that you did, for example, by vectorborne transmission in Latin America;
• received blood or organs that you donated after you already were infected;
• are your children and were born after you already were infected; or if
• there are other reasons to think that they might have Chagas disease.

In what parts of the world is Chagas disease found?

People who have Chagas disease can be found anywhere in the world. However, vectorborne transmission is confined to the Americas, principally rural areas in parts of Mexico, Central America, and South America. In some regions of Latin America, vector-control programs have succeeded in stopping this type of disease spread. Chagas disease is not endemic in the Caribbean (for example, in Puerto Rico or Cuba). Rare vectorborne cases of Chagas disease have been noted in the southern United States.