Frequently Asked Questions
Consult the Network's list of frequently asked questions, with brief answers prepared by the clinical committee.
Go to FAQChagas in Surinam
Clinical care guide based on current protocols for the diagnosis, treatment and follow-up of Chagas disease.
Diagnosis
Summary
Acute and congenital infection
- Confirm with direct parasitological concentration tests and/or PCR.
- Confirm any positive PCR in an asymptomatic newborn with a second PCR.
- Repeat testing around 30 days of life.
- If the result is negative, perform serological follow-up from 8 months of life.
Chronic infection
The decision lies with the local health authority, according to its operational, regulatory and epidemiological capacity.
- With a quality management system and verification of test performance: a single ELISA with sensitivity ≥96 % and specificity ≥97 %.
- Without those guarantees: two serological tests using different antigens (ELISA, IHA, IIF or CMIA).
Population studies
- Use a single ELISA or immunochromatographic test (ICT) with sensitivity ≥90 %.
Blood bank screening
- Use a single chemiluminescence, electrochemiluminescence or ELISA test with sensitivity ≥99.5 %.
- Refer reactive donors to a specialized center to determine their serological status.
Source: Guidelines for the diagnosis and treatment of Chagas disease. 2nd edition. PAHO, 2026
Serological tests for chronic infection
Two scenarios are considered for the diagnosis of chronic infection:
- With quality standards, quality management and verification of test performance: a single ELISA with high sensitivity (≥96 %) and high specificity (≥97 %).
- Without those guarantees: two serological tests with different antigens: ELISA, IHA, IIF or CMIA.
If two tests are used and results are discordant, perform a third test or refer the sample to a reference laboratory.
Rapid diagnostic tests are not recommended in standard algorithms; their use is restricted to screening or surveillance in settings with limited access.
Quantifying antibody titers at diagnosis allows assessment of the progressive reduction in the humoral response as an indicator of therapeutic efficacy.
Tests for acute and congenital infection
Recommended methods:
- Direct parasitological concentration tests: micromethod, microstrout and microhematocrit.
- PCR.
A negative result does not rule out infection: in congenital transmission, perform serological follow-up from 8 months of life; in non-congenital acute infection, seek seroconversion one month after case detection.
A positive direct parasitological test confirms acute infection. In symptomatic patients, a positive PCR also confirms it. In asymptomatic newborns, a positive PCR must be confirmed with a second PCR (about 4–6 % are false positives).
Peak parasitemia occurs around 30 days of life; repeating the test at that age improves detection.
Treatment
Summary
Treatment indications
- ✅ Adults without cardiopathy: antiparasitic treatment (strong recommendation).
- ✅ Children with chronic infection: antiparasitic treatment (strong recommendation).
- 🔴 Adults with cardiopathy: do not indicate antiparasitic treatment (strong recommendation).
- Young patients with mild cardiopathy, such as an isolated conduction disorder: consider treatment through shared decision-making.
- Immunocompromised patients: potential benefits may be greater.
- Cardiopathy: ensure comprehensive therapeutic support.
- ✅ Acute or congenital infection: antiparasitic treatment (strong recommendation).
- ✅ Women of childbearing age: antiparasitic treatment outside pregnancy to prevent vertical transmission (strong recommendation).
Available drugs
Benznidazole or nifurtimox, not other alternatives (azoles, fexinidazole) or drug combinations (strong recommendation); interchangeable depending on availability and the adverse-event profile.
Treatment duration
Benznidazole or nifurtimox for 30 days (conditional recommendation). Where adherence to 30 days is a barrier, a 15-day regimen may be considered.
Source: Guidelines for the diagnosis and treatment of Chagas disease. 2nd edition. PAHO, 2026
Benznidazole treatment regimen
Acute cases:
- ≤40 kg: 7.5–10 mg/kg/day orally.
- >40 kg: 5–7 mg/kg/day orally.
Congenital cases:
- 10 mg/kg/day orally.
Chronic infection:
- ≤40 kg: 7.5 mg/kg/day orally.
- >40 kg: 5 mg/kg/day orally.
In all cases: divided into 2 or 3 daily doses, for 30 days.
Adverse effects are predominantly cutaneous and neurological.
Nifurtimox treatment regimen
Acute and chronic cases:
- ≤40 kg: 10–15 mg/kg/day orally.
- >40 kg: 8–10 mg/kg/day orally.
Congenital cases:
- 10–15 mg/kg/day orally.
In all cases: divided into 2 or 3 daily doses, for 30 days.
Adverse effects are predominantly digestive and psychiatric (weight loss due to hyporexia).
Follow-up
Summary
Patients should be followed up regularly and persistently.
Criteria for treatment response
- Progressive reduction of serological titers and persistently negative parasitological tests or PCR define treatment response.
- Serological negativization is observed in the long term.
- Quantifying antibody titers at diagnosis makes it possible to monitor their reduction.
Special populations
- In immunocompromised patients (HIV, transplant, immunosuppressants), monitor for reactivation of the infection (mean observed rate 27.9 %).
Post-treatment follow-up
- Perform periodic clinical and serological follow-up after antiparasitic treatment.
Source: Guidelines for the diagnosis and treatment of Chagas disease. 2nd edition. PAHO, 2026
Pregnancy and Congenital Chagas
Summary
Screening in pregnancy
Vertical transmission of T. cruzi occurs in 1–6 % of newborns of infected pregnant women; screening is the only effective strategy to identify them, since most are asymptomatic at birth.
- Request serology at the beginning and at the end of pregnancy in endemic areas.
Treatment
- Do not treat during pregnancy or breastfeeding.
- Treat women of childbearing age outside pregnancy, ruling out pregnancy before starting it (strong recommendation).
- Treatment strongly reduces the probability of vertical transmission.
Newborn
- Test with direct parasitological concentration tests (micromethod, microstrout or microhematocrit) and/or PCR.
- Confirm any positive PCR in an asymptomatic newborn with a second PCR.
- Repeat testing around 30 days of life, when peak parasitemia occurs.
- If the result is negative, perform serological follow-up from 8 months of life.
- Treatment in the first year of life achieves a high cure rate.
Source: Guidelines for the diagnosis and treatment of Chagas disease. 2nd edition. PAHO, 2026
Pediatrics
Summary
Treat all children with chronic T. cruzi infection (strong recommendation).
- Duration: 30 days; consider a 15-day regimen if adherence is a barrier.
- Pediatric formulations of benznidazole and nifurtimox are available.
- Perform regular and sustained follow-up, with clinical and serological monitoring.
Benefits of early treatment
- Better treatment tolerance than in adults.
- Lower frequency and intensity of adverse effects.
- Higher probability of serological negativization.
- In girls, reduced risk of future congenital transmission.
Source: Guidelines for the diagnosis and treatment of Chagas disease. 2nd edition. PAHO, 2026
Adverse Reactions
Summary
Adverse effects of antiparasitic treatment appear mainly between 15 and 30 days of treatment, with greater frequency and intensity at older ages.
Profile by drug
- Benznidazole: cutaneous and neurological reactions.
- Nifurtimox: weight loss due to hyporexia and psychiatric adverse effects.
Common adverse effects
- Skin rash, digestive disorders, general symptoms (fever, arthromyalgia), headache, irritability, paresthesia, elevated transaminases and eosinophilia.
- They are generally mild or moderate; manage with symptomatic treatment.
Serious adverse effects
- Uncommon: leukopenia, neutropenia, thrombocytopenia and Stevens-Johnson syndrome.
- Treatment discontinuation due to adverse effects is infrequent, especially in children.
Duration and frequency of adverse effects
- Thirty-day regimens are associated with fewer adverse effects than 31–60-day regimens.
- With benznidazole: approximately 4.9 % vs 10.2 %, less toxicoderma and fewer interruptions.
- In children aged 12 years or younger, adverse effects are less frequent (approximately 1.8 %) than in those older than 12 years (approximately 11 %).
Source: Guidelines for the diagnosis and treatment of Chagas disease. 2nd edition. PAHO, 2026
Surveillance
Summary
PAHO recommends that Member States:
- Include Chagas disease among the vertically transmitted conditions to be screened in women of childbearing age.
- Ensure the provision of benznidazole and nifurtimox and access to health services, especially for populations with disadvantaged access.
- Implement systematic case finding and training of health teams in diagnosis and treatment.
- Coordinate levels of care to ensure continuity of care.
- Strengthen information systems and epidemiological surveillance.
Implementation barriers and strategies
- Barriers: lack of knowledge of the guidelines among health personnel, shortage of diagnostic and therapeutic supplies, geographic and socioeconomic access difficulties and limited human resources.
- Strategies: training, materials, digital reminders in medical records, supportive policies, decision-support systems, audit and feedback, dissemination and administrative support.
Source: Guidelines for the diagnosis and treatment of Chagas disease. 2nd edition. PAHO, 2026
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