Screen patients for Chagas disease if they have a history of residence in or prolonged travel to Mexico, continental Central America, or continental South America.
Chagas disease is a vector-borne parasitic disease that, when left untreated, can lead to chronic cardiac and gastrointestinal symptoms, adverse pregnancy outcomes, and congenital Chagas disease in infants.
Current situation
Washington State Department of Health (DOH) recently estimated more than 300,000 Washington residents meet screening criteria for Chagas disease—and only an estimated 0.02–0.03% of these residents have been screened.
DOH estimates more than 2,500 Washington residents could be living with untreated infections of Trypanosoma cruzi, the parasite that causes Chagas disease. If untreated, these cases could lead to an estimated 21–56 infants with preventable congenital Chagas disease infections every 10 years.
Most people infected with T. cruzi don’t know they have the disease—which is why provider screening is essential. .
Requested actions
- Screen patients for Chagas disease if they meet any of the following criteria:
- Born in Mexico, continental Central America, or continental South America or lived in these areas for 6 months or longer. Of particular concern are those who are:
- Pregnant.
- Immunocompromised.
- Family members of people diagnosed with Chagas disease who share travel or residence exposure.
- People whose gestational parent was diagnosed with Chagas disease.
- Born in Mexico, continental Central America, or continental South America or lived in these areas for 6 months or longer. Of particular concern are those who are:
- Chagas disease has acute and chronic phases, and screening testing is different depending on the stage.
- Acute Chagas disease is commonly diagnosed by microscopy or polymerase-chain reaction (PCR) testing.
- Use these methods to screen infants suspected to have congenital Chagas disease.
- Use Centers for Disease Control and Prevention’s (CDC’s) algorithms to guide Chagas testing for infants:
- See CDC’s clinical considerations for congenital Chagas disease for more information.
- Immunosuppressed patients may experience reactivation of chronic Chagas disease. PCR testing is appropriate for these patients.
- Chronic Chagas disease is diagnosed by serologic testing for T. cruzi antibodies.
- Most patients with Chagas in Washington are expected to have chronic Chagas disease, as the insect vector that spreads T. cruzi parasites are not present in Washington.
- Acute Chagas disease is commonly diagnosed by microscopy or polymerase-chain reaction (PCR) testing.
- Order a T. cruzi serologic test for all patients who meet the above criteria for chronic Chagas disease.
- Most commercial labs offer a T. cruzi serologic test.
- If initial T. cruzi serology is positive, order confirmatory serologic testing to confirm the diagnosis of Chagas disease.
- No single serologic test is sensitive and specific enough to diagnose Chagas disease. At least 2 different serologic tests are recommended.
- Many large commercial labs, including Mayo Clinic and Quest Diagnostics, also offer confirmatory testing for Chagas disease.
- Patients typically only need to provide 1 serum sample for use in multiple serologic tests.
- Ask your commercial lab whether positive serology automatically reflexes to a second confirmatory test, or if the confirmatory test needs to be coordinated through public health.
- If the lab does not offer confirmatory testing, contact the Local Health Jurisdiction in the patient’s county of residence to forward the specimen for confirmatory testing through public health.
- Once diagnosis of Chagas disease is confirmed, screen patients for cardiac or gastrointestinal complications and assess for treatment.
- Patients diagnosed with Chagas disease are recommended to receive:
- Electrocardiogram (ECG) repeated annually.
- Echocardiogram.
- Chest x-ray, if an echocardiogram is not possible.
- Patients diagnosed with Chagas disease are recommended to receive:
- Treat all cases of acute or reactivated Chagas disease and all chronic infections in children younger than 18 years with antiparasitic drugs:
- Nifurtimox and benznidazole are Food and Drug Administration- (FDA-) approved for treatment of T. cruzi infections in pediatric patients. See CDC’s clinical care of Chagas disease for dosage and treatment duration recommendations.
- Use of antiparasitic drugs to treat a patient outside of the FDA-approved age ranges (0–18 years for nifurtimox, 2–12 years for benznidazole) is based on clinical diagnosis and decision by the treating provider.
- Treatment is also recommended for adults 18–50 years old with chronic Chagas disease without advanced cardiomyopathy.
- For adults older than 50 years with chronic infection, the decision to treat should be individualized. See CDC’s clinical care of Chagas disease for more details.
- Treatment is not indicated for people who are pregnant or breastfeeding and should be delayed until after birth or cessation of breastfeeding.
- Report cases of Chagas disease within 3 business days. Call (253) 649-1412 and ask to speak with a General Communicable Disease Investigation Nurse.
Background
Chagas disease is a vector-borne illness caused by the protozoan parasite Trypanosoma cruzi. T. cruzi is spread through the feces of infected triatomine bugs (also called “kissing bugs”), which are endemic to areas of Mexico, continental Central America, and continental South America. T. cruzi can also be passed congenitally and through infected blood or organ products. Triatomine insects are not endemic to Washington. Most cases of Chagas disease diagnosed in Washington are among people born in Latin America or their children. In the United States, some southern states have seen limited reports of possible Chagas disease transmission.
Chagas disease has both an acute and a chronic phase. Acute Chagas disease infections are often asymptomatic, but patients can present with nonspecific symptoms. Acute Chagas disease, when untreated, can resolve within weeks or months to a subclinical chronic infection. Some (20%–30%) cases of Chagas disease can progress to a symptomatic chronic illness that may include severe cardiac and gastrointestinal involvement leading to fatal complications. Untreated Chagas disease can also lead to adverse outcomes in pregnant people and their infants. Congenital Chagas cases should be managed as acute Chagas infections. Treatment will prevent potential severe complications for infants (including meningoencephalitis, pneumonitis, and death) and prevent complications from chronic Chagas disease later in life.
Acute Chagas infections can be diagnosed through PCR and microscopy of thick and thin blood smears. Chronic Chagas disease is diagnosed through serologic tests that detect T. cruzi antibodies. No single test is sufficiently sensitive and specific enough for diagnosis. Clinicians are recommended to use 2 or more tests that can detect antibodies to different antigens. Common techniques include enzyme-linked immunosorbent assay (ELISA) and immunofluorescent antibody test (IFA).
Antiprotozoal treatment (benznidazole or nifurtimox) is indicated for all acute and reactivated infections, and for all chronic infections in people younger than 18 years. Treatment is strongly recommended for people younger than 50 years without advanced cardiomyopathy. People diagnosed with Chagas disease should be evaluated for potential cardiac and gastrointestinal complications.
Contact
To report suspected cases or for help with questions, call (253) 649-1412 and ask to speak with a General Communicable Disease Investigation Nurse.
Resources
- DOH:
- CDC:
- United States Chagas Diagnostic Working Group: