Frequently Asked Questions
Consult the Network's list of frequently asked questions, with brief answers prepared by the clinical committee.
Go to FAQChagas in Guatemala
Clinical care guide based on current protocols for the diagnosis, treatment and follow-up of Chagas disease.
Diagnosis
Summary
Acute phase
Acute phase: parasitological methods; the sample is taken in the first 15 to 45 days (children under 7 years, 15 days) (Module 6 (Adult), 2025, pág. 896; Module 3 (Childhood), 2025, pág. 426).
- Suspect with fever for more than 10 days, chagoma, Romaña sign or lymphadenopathy 48 hours after inoculation.
- Look for anaemia, hepatomegaly and splenomegaly on physical examination.
- Bear in mind that most acute cases are asymptomatic.
Module 6 (Adult), 2025, pág. 895; Surveillance 2018, pág. 49.
Chronic phase
Chronic phase: ELISA for IgG antibodies against T. cruzi and two positive serological tests of different principle or antigens (Module 6 (Adult), 2025, pág. 896; Surveillance 2018, pág. 49).
- Differentiate, after 60 days, indeterminate chronic disease (two reactive tests, normal electrocardiogram and X-ray) from determinate disease (with cardiac or digestive lesion).
- About 30 % of infected people develop cardiac lesions and around 10 %, digestive alterations.
Surveillance 2018, pág. 50.
Screen blood donors and women of childbearing age and pregnant women (Module 6 (Adult), 2025, pág. 896).
Newborn
Newborn: parasitology on cord or peripheral blood and, if negative, serology from 8 months of age (Module 2 (Newborn), 2025, pág. 220).
- Most are asymptomatic; suspect with fever, hepatomegaly or splenomegaly, low birth weight, respiratory distress, jaundice, meningoencephalitis, myocarditis or eye lesions.
- Confirm the case in a child under 28 days with positive direct parasitology or two confirmed serological tests.
- Parasitology may be positive up to 2 months and serology is performed from 8 months.
Module 2 (Newborn), 2025, pág. 221; Surveillance 2018, pág. 49.
Sample collection and shipment
- Use whole blood with EDTA in the acute phase and serum without additive in the chronic phase.
- Send the sample with the surveillance form to the area laboratory or the National Health Laboratory within the first 24 to 48 hours.
- If no trained staff are available, send blood with EDTA in a cold chain (+2 to +8 °C) within the first 24 hours.
- With an indeterminate result, request a new sample.
Module 6 (Adult), 2025, pág. 896; Surveillance 2018, pág. 51 and pág. 52.
Source: Normas de Atención Integral para la Red Integrada de Servicios de Salud (MSPAS/DNPAP, Guatemala, 2025; Ministerial Agreement 144-2025) and Protocolos de Vigilancia Epidemiológica. Enfermedades Vectoriales de Origen Parasitario (MSPAS, Guatemala, October 2018)
Manifestations in adults
In adults it presents with dyspnoea, palpitations, dizziness, lower limb oedema, constipation, dysphagia or megaoesophagus (Module 6 (Adult), 2025, pág. 896).
Confirmation of the acute phase
- Analyse the sample the same day with the Strout technique.
- If negative, repeat after 10 days; if still negative, perform ELISA after 2 months.
Surveillance 2018, pág. 51.
Treatment
Summary
Two drugs: benznidazole (100 mg, 50 mg and 12.5 mg) and nifurtimox (120 mg and 30 mg), in 2 to 3 daily doses for 60 days (Module 6 (Adult), 2025, pág. 898).
Before starting treatment
Before starting: blood count, renal function and transaminases, and a mandatory pregnancy test in every woman of childbearing age (Module 6 (Adult), 2025, pág. 897).
- Confirm the positive serology performed at the Dirección del Laboratorio Nacional de Salud or at the reference laboratories.
- Inform about benefits, risks and consequences; treatment must be supervised and administered by health personnel.
Module 6 (Adult), 2025, págs. 897-898.
Contraindications and precautions
Do not administer in chronic alcoholism, renal or hepatic failure, severe associated lesions or hypersensitivity (Module 6 (Adult), 2025, pág. 898).
- Avoid alcoholic drinks, fat, fried food and spicy food, and prolonged sun exposure.
Module 6 (Adult), 2025, pág. 898.
Source: Normas de Atención Integral para la Red Integrada de Servicios de Salud (MSPAS/DNPAP, Guatemala, 2025; Ministerial Agreement 144-2025) and Protocolos de Vigilancia Epidemiológica. Enfermedades Vectoriales de Origen Parasitario (MSPAS, Guatemala, October 2018)
Regimens and doses
The table leaves the maximum dose open («may vary by country», 300 mg/day 400 mg/day); in childhood: 400 mg/day of benznidazole and 700 mg/day of nifurtimox (Module 6 (Adult), 2025, pág. 898; Module 3 (Childhood), 2025, pág. 427).
Newborn
- Treat the full-term newborn with benznidazole 7-10 mg/kg/day or nifurtimox 10-15 mg/kg/day, in 2 to 3 doses, for 60 days.
- In premature or low-birth-weight infants, start with 5 mg/kg/day divided every 12 hours in the first week and then 10 mg/kg/day divided every 12 hours.
- Treat as soon as the diagnosis is confirmed, under medical supervision.
Module 2 (Newborn), 2025, pág. 221.
Childhood
- Benznidazole: 7.5 mg/kg/day up to 40 kg and 5 mg/kg/day above 40 kg, in three doses, 60 days; maximum 400 mg/day.
- Nifurtimox: 10 mg/kg/day up to 40 kg and 8 mg/kg/day above 40 kg, in three doses, 60 days; maximum 700 mg/day.
- Refer every confirmed case to a hospital for electrocardiogram, chest X-ray and echocardiogram before treatment.
Module 3 (Childhood), 2025, pág. 427.
Adults
- Benznidazole in acute disease: 7.5-10 mg/kg/day up to 40 kg and 5-7 mg/kg/day above 40 kg.
- Nifurtimox in acute disease: 10-15 mg/kg/day up to 40 kg and 8-10 mg/kg/day above 40 kg.
- In congenital disease: benznidazole 10 mg/kg/day or nifurtimox 10-15 mg/kg/day.
- Benznidazole in chronic disease: 7.5-10 mg/kg/day up to 40 kg and 5 mg/kg/day above 40 kg.
- Nifurtimox in chronic disease: 10 mg/kg/day up to 40 kg and 8 mg/kg/day above 40 kg.
- Suggest treatment in chronic infection without specific organ damage; there is no age limit, but the risk-benefit balance must be assessed.
Module 6 (Adult), 2025, pág. 898, Table 34; pág. 897.
Follow-up
Summary
Initial assessment
- Indicate electrocardiogram, chest X-ray and echocardiogram in adults; the echocardiogram is useful with palpitations, syncope, arrhythmias or ventricular extrasystoles.
- In asymptomatic children with a normal physical examination, an electrocardiogram would be sufficient to classify the case.
Module 6 (Adult), 2025, pág. 897; Module 3 (Childhood), 2025, pág. 427.
Monitoring during treatment
Assess the person at intervals of no more than 15 days during treatment, with monitoring of blood count, urine, transaminases, creatinine and urea nitrogen (Module 6 (Adult), 2025, pág. 898; Module 3 (Childhood), 2025, pág. 427).
- Supervise treatment with support from lead teachers, health personnel or family members.
Module 6 (Adult), 2025, pág. 898.
After finishing treatment, take samples at 6 months (acute Chagas disease) and at 18 months (chronic disease), and then every year until they become negative (Module 3 (Childhood), 2025, pág. 427).
In late chronic Chagas disease eligible for treatment, follow up every 12 months with electrocardiogram and laboratory tests (Module 6 (Adult), 2025, pág. 898).
Refer to hospital cases complicated by cardiac signs, megacolon or central nervous system involvement (Module 3 (Childhood), 2025, pág. 427).
Detection in the family
- Screen daughters and sons, first-degree family members and household contacts of people with Chagas disease.
- Screen women of childbearing age.
- Suspect the disease in children of mothers with Chagas disease and in first-degree household contacts, even without symptoms.
Module 6 (Adult), 2025, pág. 899; Module 3 (Childhood), 2025, pág. 426.
Source: Normas de Atención Integral para la Red Integrada de Servicios de Salud (MSPAS/DNPAP, Guatemala, 2025; Ministerial Agreement 144-2025) and Protocolos de Vigilancia Epidemiológica. Enfermedades Vectoriales de Origen Parasitario (MSPAS, Guatemala, October 2018)
Follow-up of congenital disease
- Refer the child of a seropositive mother in the first month; if negative, repeat one month later and serology at 9, 12 and 18 months.
- Apply the 2025 Standards: tests seeking the parasite at 2, 9, 12 and 18 months.
Surveillance 2018, pág. 52; Module 2 (Newborn), 2025, pág. 223; Module 3 (Childhood), 2025, pág. 428.
Pregnancy and Congenital Chagas
Summary
Who to treat
Do not treat the chronic phase in pregnancy; acute disease is managed at a higher level and the puerperium is treated, without suspending breastfeeding (Module 1 (Pregnancy), 2025, págs. 71-72).
- Chronic Chagas disease: do not indicate treatment; perform clinical assessment with electrocardiogram and classify (uncomplicated, heart disease, among others).
- Acute Chagas disease: indicate treatment, assess maternal-fetal risk and manage at a higher level of care.
- Puerperium: indicate treatment, do not suspend breastfeeding and assess adverse reactions.
- With cardiac, oesophageal or colon complications, refer to hospital for assessment and follow-up.
Module 1 (Pregnancy), 2025, pág. 72.
Screening
Screen every pregnant woman before 28 weeks of gestation; in endemic areas, if there was no timely antenatal care, screen at the time of delivery (Module 1 (Pregnancy), 2025, pág. 71).
- Repeat serology in every pregnancy: a positive woman can transmit the parasite in each one.
- Breastfeeding does not cause congenital Chagas disease.
Module 1 (Pregnancy), 2025, pág. 72; Surveillance 2018, pág. 48.
Mother-to-child transmission occurs in between 2 and 8 % of pregnancies in infected mothers (Module 6 (Adult), 2025, pág. 895).
Newborn
- Perform parasitology on cord blood or peripheral blood at birth.
- Confirm the case in a child under 28 days with direct parasitology positive up to the ninth month or two serological tests.
- If parasitology is negative, perform serology from 8 months of age.
- Follow the algorithm in Figure 26 of Module 2 (pág. 222).
Module 2 (Newborn), 2025, pág. 220; Surveillance 2018, pág. 49.
Notify and enter the mother and newborn in SIGSA, and refer the pregnant woman to the nearest hospital (Module 1 (Pregnancy), 2025, pág. 71).
Source: Normas de Atención Integral para la Red Integrada de Servicios de Salud (MSPAS/DNPAP, Guatemala, 2025; Ministerial Agreement 144-2025) and Protocolos de Vigilancia Epidemiológica. Enfermedades Vectoriales de Origen Parasitario (MSPAS, Guatemala, October 2018)
Screening according to the 2018 Surveillance
The 2018 surveillance protocol sets serological testing from week 28 of gestation in pregnant women from endemic areas (pág. 52) and considers screening of pregnant women a route of passive surveillance (pág. 51).
Pediatrics
Summary
Acute Chagas disease: first 60 days, ICD-10 B57.1; chronic Chagas disease: ICD-10 B57.2, «after 60 days or indeterminate» (Module 3 (Childhood), 2025, págs. 425-426).
Acute phase
- Suspect with fever for more than 10 days, chagoma, Romaña sign or lymphadenopathy 48 hours after inoculation.
- Look for anaemia, hepatomegaly and splenomegaly; the acute form is usually asymptomatic in childhood.
Module 3 (Childhood), 2025, pág. 425; Module 6 (Adult), 2025, pág. 895.
Chronic phase
- Suspect with fatigue, palpitations, dizziness, syncope, dyspnoea or lower limb oedema.
Module 3 (Childhood), 2025, pág. 426.
Newborn
- Most are asymptomatic; confirm the case in a child under 28 days with positive direct parasitology or two confirmed serological tests.
Module 2 (Newborn), 2025, pág. 221; Figure 26 (pág. 222) summarises the diagnosis, registration and notification algorithm.
Suspect in children of women with Chagas disease, in household contacts or first-degree relatives and in residents of endemic areas; perform serology in pre-school and school-age children (Module 3 (Childhood), 2025, pág. 426).
Treatment: benznidazole 7.5 mg/kg/day up to 40 kg and 5 mg/kg/day above 40 kg; nifurtimox 10 mg/kg/day up to 40 kg and 8 mg/kg/day above; 60 days, maximums 400 mg/day and 700 mg/day (Module 3 (Childhood), 2025, pág. 427).
Early detection and treatment are a public health priority: good tolerance and high serological response (Module 3 (Childhood), 2025, pág. 427).
Source: Normas de Atención Integral para la Red Integrada de Servicios de Salud (MSPAS/DNPAP, Guatemala, 2025; Ministerial Agreement 144-2025) and Protocolos de Vigilancia Epidemiológica. Enfermedades Vectoriales de Origen Parasitario (MSPAS, Guatemala, October 2018)
Before treating
- Refer every confirmed case to a hospital for electrocardiogram, chest X-ray and echocardiogram.
- In asymptomatic children with a normal physical examination, an electrocardiogram would be sufficient.
- Monitor nutritional status before, during and after the medication.
Module 3 (Childhood), 2025, pág. 427.
Follow-up of the treated child
- Take samples at 6 months (acute Chagas disease) and at 18 months (chronic disease), and every year until they become negative.
- In congenital Chagas disease, continue with tests seeking the parasite at 2, 9, 12 and 18 months.
- Refer to hospital in case of adverse reactions or other complications.
Module 3 (Childhood), 2025, pág. 427 and pág. 428.
Adverse Reactions
Summary
Most ADRs appear between days 15 and 30, are mild or moderate and do not require suspending treatment; they increase with age (Module 6 (Adult), 2025, pág. 898).
Table 34 A grades frequency: dermatitis +++ with benznidazole; with nifurtimox, +++ anorexia, psychic excitement, gastralgia and vomiting; bone marrow depletion scarce with benznidazole and absent with nifurtimox (Module 6 (Adult), 2025, pág. 899).
Pharmacovigilance
- Assess at intervals of no more than 15 days and treat ADRs symptomatically.
- Refer adverse reactions or complications to hospital.
- Bear in mind that children tolerate treatment well, with high serological negativisation.
Module 6 (Adult), 2025, pág. 898; Module 3 (Childhood), 2025, pág. 427.
Some ADRs may be serious: explain the warning signs and the importance of follow-up appointments (Module 6 (Adult), 2025, pág. 899).
The 2025 Standards treat ADRs symptomatically, but do not set criteria for definitive suspension or stepwise management (Module 6 (Adult), 2025, págs. 898-899).
Source: Normas de Atención Integral para la Red Integrada de Servicios de Salud (MSPAS/DNPAP, Guatemala, 2025; Ministerial Agreement 144-2025) and Protocolos de Vigilancia Epidemiológica. Enfermedades Vectoriales de Origen Parasitario (MSPAS, Guatemala, October 2018)
Frequency of ADRs (Table 34 A)
Table 34 A compares the two drugs symptom by symptom; key: - absent, + scarce, ++ moderate, +++ high. The same table applies to children:
- Anorexia: ++ with benznidazole / +++ with nifurtimox
- Headache: + / ++
- Dermatitis: +++ / +
- Psychic excitement: absent / +++
- Gastralgia: + / +++
- Insomnia: + / ++
- Dizziness: ++ / +++
- Weight loss: + / ++
- Polyneuropathy: + / ++
- Bone marrow depletion: + / absent
- Vomiting: ++ / +++
Table 34 A adapted from the Chagas DNDI app (PAHO 2018); Guatemala, 2023 (Module 6 (Adult), 2025, pág. 899).
Module 3 (Childhood), 2025: good nutrition during treatment and risk of reinfection (pág. 428).
Surveillance
Summary
Every confirmed case —acute or chronic— must be notified on a mandatory basis to the Dirección de Epidemiología y Gestión del Riesgo (Module 6 (Adult), 2025, pág. 896; Module 2 (Newborn), 2025, pág. 221).
Notification is immediate within the first 24 hours of identifying the case; a case in a non-endemic area is considered an outbreak and its investigation begins within 24 hours, with a report after 15 days (Surveillance 2018, pág. 53).
Active and passive surveillance
- Actively search for acute and chronic cases and take laboratory samples.
- Carry out seroprevalence surveys in risk groups, especially children under 15 years and pregnant women.
- In passive surveillance, screen pregnant women during antenatal care and in blood banks.
Surveillance 2018, pág. 51.
For the patient and contacts
- Treat all acute and chronic cases according to the current standards.
- Take blood samples from contacts to confirm or rule out the disease.
Surveillance 2018, pág. 54.
Vector control
- Manage the vector in an integrated way, with cleaning and tidying of the intra- and peridomestic area.
- Replaster walls, replace roofs with permanent materials and improve floors.
- Search for kissing bugs with DDRISS vector personnel and community volunteers.
- Move beds away from walls, avoid overcrowding and do not keep animals inside the dwelling.
Surveillance 2018, pág. 54; Module 6 (Adult), 2025, pág. 899.
Module 6 refers to the Manual para la vigilancia y control de Triatoma dimidiata (2021) (Module 6 (Adult), 2025, pág. 899).
Source: Normas de Atención Integral para la Red Integrada de Servicios de Salud (MSPAS/DNPAP, Guatemala, 2025; Ministerial Agreement 144-2025) and Protocolos de Vigilancia Epidemiológica. Enfermedades Vectoriales de Origen Parasitario (MSPAS, Guatemala, October 2018)
Case definitions
- Suspected acute case: prolonged fever, chagoma, lymphadenopathy or hepatosplenomegaly, with a history of endemic area, transfusion, recent transplant or infected mother.
- Confirmed acute case: direct parasitological methods (fresh drop, Strout and microhaematocrit).
- Confirmed chronic case: two positive serological tests of different principle or antigens.
- Confirmed congenital case: direct parasitology up to the ninth month or two serological tests after 10 months of age.
Surveillance 2018, pág. 49. In chronic cases, the two serological tests must use different antigens or principles (pág. 52).
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