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Health condition · Clinically reviewed

Chagas disease, a silent parasite with lifelong consequences.

Trypanosoma cruzi is endemic in Latin America and imported into the UK. Screening, antiparasitic therapy and cardiac follow-up all change outcomes.

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Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against UKHSA, WHO, PAHO and peer-reviewed tropical-medicine sources.

  • 03

    Current for 2026

    Reflects modern UK practice for imported Chagas, including screening in pregnancy and specialist referral pathways.

Key facts

Chagas disease at a glance.

The essentials, in plain English - what it is, how it spreads and what treatment can achieve.

  • What it is

    A parasitic infection caused by Trypanosoma cruzi, endemic to Latin America and imported into the UK through migration and travel.

  • How it spreads

    Triatomine "kissing bug" faeces, blood transfusion, organ transplant, mother-to-child in pregnancy and contaminated food or juice.

  • Three phases

    Acute (weeks), chronic indeterminate (years to decades of silence) and chronic symptomatic cardiac or digestive disease.

  • Cardiac risk

    Around 30 percent develop dilated cardiomyopathy, arrhythmia or heart block. It is the leading cause of Chagas-related death.

  • Digestive risk

    Around 10 percent develop megaoesophagus or megacolon, sometimes decades after the initial infection.

  • Antiparasitic

    Benznidazole is first-line for 60 days. Nifurtimox is the alternative. Both are most effective in the acute and congenital settings.

Why this guide matters

A hidden diagnosis, a treatable disease.

Chagas often reaches UK clinics decades after infection. Recognition, screening and early treatment protect the heart and prevent onward transmission.

  • Screening changes lives

    In UK Latin American communities and in pregnancy, a simple serology test uncovers silent chronic infection that would otherwise present with heart failure.

  • Antiparasitic therapy has limits

    Benznidazole cures acute and congenital disease. In chronic disease it clears the parasite but does not reverse established cardiomyopathy.

  • Cardiac care is the priority

    Chagas cardiomyopathy causes most deaths - modern heart-failure therapy, devices and transplantation transform prognosis when applied early.

How the diagnosis is made

From exposure history to a confirmed diagnosis.

The steps a UK GP, infectious-diseases or tropical-medicine team will normally follow, in order - so you know what to expect and why.

  1. 01

    Assessing

    History and exposure

    Country of birth, time in endemic Latin America, family origin, blood transfusion or transplant history and pregnancy status.

  2. 02

    Assessing

    Clinical examination

    Look for Romana sign (unilateral eye swelling), chagoma, fever and signs of heart failure or oesophageal disease.

  3. 03

    Assessing

    Screening in at-risk groups

    Serology in immigrants from endemic areas, pregnant women with Latin American origin, and blood or organ donors.

  4. 04

    Confirming

    Serology - two tests required

    Diagnosis relies on two different serological assays: ELISA, IHA (indirect haemagglutination) and IIF (indirect immunofluorescence).

  5. 05

    Confirming

    PCR and microscopy

    PCR and direct blood or CSF microscopy are used in the acute phase, congenital cases and immunosuppression-related reactivation.

  6. 06

    Staging

    Cardiac workup

    ECG for conduction disease, echocardiogram for ventricular function and Holter monitoring for arrhythmia detection.

  7. 07

    Staging

    Digestive workup

    Barium swallow and enema plus endoscopy where megaoesophagus or megacolon is suspected.

Typical timeline: from first serology to a full staging picture within weeks.

Symptoms

What Chagas disease actually looks like.

Acute signs at the bite site, a long silent interval, and a spectrum of cardiac and digestive disease that appears years later.

  • Romana sign

    Painless unilateral eyelid and periorbital swelling at the site of a kissing-bug bite, classic for acute Chagas.

  • Chagoma

    A firm, red, indurated skin lesion at the site of parasite entry, appearing in the acute phase.

  • Acute fever

    A prolonged low-grade fever with malaise, lymphadenopathy and hepatosplenomegaly, often mistaken for a viral illness.

  • Cardiac symptoms

    Palpitations, breathlessness, syncope or heart failure - the dominant presentation of chronic symptomatic disease.

  • Digestive symptoms

    Dysphagia, regurgitation, chronic constipation and abdominal distension from megaoesophagus or megacolon.

  • Silent chronic phase

    Years or decades with no symptoms but positive serology - the reason screening matters for at-risk groups.

  • Congenital infection

    Vertical transmission from mother to baby - often silent at birth but curable if treated early.

  • Red flag - sudden collapse

    Syncope, ventricular tachycardia or sudden cardiac death can be the first sign of Chagas cardiomyopathy.

Treatment

How Chagas disease is treated in the UK.

Antiparasitic therapy where it clearly benefits, disciplined cardiac care, digestive surgery when needed, and coordinated specialist follow-up.

  • Benznidazole

    First-line antiparasitic at 5 to 7 mg/kg/day for 60 days. Most effective in acute, congenital and reactivated disease.

  • Nifurtimox

    Alternative antiparasitic at 8 to 10 mg/kg/day for 60 days, used when benznidazole is not tolerated or unavailable.

  • Heart failure therapy

    ACE inhibitors or ARBs, beta-blockers, mineralocorticoid antagonists and diuretics, following standard UK heart-failure pathways.

  • Antiarrhythmic and device therapy

    Amiodarone for symptomatic arrhythmia, implantable cardioverter-defibrillator for ventricular tachycardia and pacemakers for heart block.

  • Heart transplantation

    A selective option in end-stage Chagas cardiomyopathy, with careful post-transplant monitoring for parasite reactivation.

  • Digestive surgery

    Pneumatic dilatation, Heller myotomy or surgical resection for advanced megaoesophagus and megacolon.

  • Congenital treatment

    Neonatal antiparasitic therapy achieves very high cure rates when started early. Prevention starts with antenatal screening.

  • Donor screening and MDT care

    Blood and organ donor screening in high-risk groups, plus multidisciplinary care through specialist tropical-medicine and Chagas services.

What this guide is based on

The sources behind every claim on this page.

UK public-health, international and specialist society guidance, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP, infectious-diseases team or tropical-medicine specialist knows your history and can tell you which parts apply to you. If in doubt, get seen.

  • UK Health Security Agency (UKHSA). Chagas disease: guidance and notifiable-disease reporting.

  • World Health Organization (WHO). Chagas disease fact sheet and treatment guidelines.

  • Pan American Health Organization (PAHO). Guidelines for the diagnosis and treatment of Chagas disease.

  • BENEFIT investigators. Randomised trial of benznidazole in chronic Chagas cardiomyopathy.

Red flags

When Chagas disease needs urgent attention.

The situations where a specialist opinion, hospital care or public-health notification cannot wait.

  • Acute myocarditis

    Severe chest pain, breathlessness or acute heart failure during the acute phase - a rare but serious emergency needing hospital care.

  • Ventricular tachycardia

    Sustained VT or syncope in chronic Chagas cardiomyopathy - urgent cardiology assessment and consideration for an implantable defibrillator.

  • Complete heart block

    New syncope with bradycardia or high-grade atrioventricular block warrants urgent pacing assessment.

  • Meningoencephalitis

    Rare in acute infection and more common in reactivation with HIV or transplant immunosuppression - a neurological emergency.

  • Reactivation in immunosuppression

    HIV, transplant or chemotherapy can trigger reactivation - a low threshold for PCR testing and specialist input is essential.

  • Pregnancy with positive serology

    Refer to specialist services for neonatal follow-up and testing. Antiparasitic therapy is deferred until after delivery and breastfeeding.

  • Post-transplant reactivation

    Recipients of organs from seropositive donors need surveillance PCR and pre-emptive therapy if positive.

  • Oral outbreak features

    A cluster of acute cases linked to contaminated juice or food needs immediate public-health notification to UKHSA.

  • Notifiable disease

    Chagas is a reportable disease in the UK - clinicians should notify UKHSA and involve tropical-medicine services promptly.

Living with it

A treatable infection, with lifelong follow-up.

Four things that make the biggest difference: getting tested if you are at risk, screening in pregnancy, an annual cardiac review and a link to a specialist Chagas service.

A quiet reminder

Silent does not mean safe.

Years of no symptoms are the norm in chronic Chagas. Testing and follow-up are how we catch the damage before it happens.

  1. 01 Screening

    Get tested if you are at risk

    If you were born in or lived in endemic Latin America, ask your GP about serology - the chronic phase is silent for decades.

  2. 02 Pregnancy

    Antenatal serology matters

    Screening in pregnancy allows early treatment of the baby after delivery, which is highly curative.

  3. 03 Follow-up

    Annual cardiac review

    Even with no symptoms, an ECG and echocardiogram every year help catch early cardiomyopathy or arrhythmia.

  4. 04 Support

    Specialist Chagas services

    UK tropical-medicine centres and the Chagas Hub coordinate diagnosis, treatment and family screening.

Frequently asked

Everything we get asked about Chagas disease.

Quick answers on transmission, testing, antiparasitic treatment and cardiac risk.

  • What is Chagas disease?

    Chagas disease, or American trypanosomiasis, is a parasitic infection caused by Trypanosoma cruzi. It is endemic in Latin America and reaches the UK through migration and travel. It has an acute phase followed by a lifelong chronic phase that can silently damage the heart or gut.

  • How do you catch it?

    Most infections in endemic areas come from the faeces of the triatomine "kissing bug" being rubbed into the bite or a mucous membrane. In the UK the main routes are congenital transmission from mother to baby, blood transfusion or organ transplant from an infected donor, and rarely contaminated food or juice.

  • What are the symptoms?

    The acute phase is often silent but can cause the Romana sign (one-sided eye swelling), a chagoma at the bite site and fever. The chronic indeterminate phase has no symptoms. Later, up to a third develop cardiac disease with heart failure or arrhythmia, and around one in ten develop megaoesophagus or megacolon.

  • Can Chagas disease be cured?

    Antiparasitic treatment with benznidazole or nifurtimox is highly effective in the acute phase, in congenital infection and in reactivation. In the chronic phase the drugs reduce parasite load but the benefit for established cardiomyopathy is uncertain, as the BENEFIT trial showed. Treatment is still recommended for younger adults, children and women of reproductive age.

  • Who should be screened in the UK?

    Screening is recommended for people born in or with long residence in endemic Latin America, pregnant women from these communities, family members of confirmed cases and, in relevant settings, blood and organ donors. Chagas is a notifiable disease and cases should be reported to UKHSA.

  • How is Chagas cardiomyopathy treated?

    It is managed as any other dilated cardiomyopathy with heart-failure medication, arrhythmia control, implantable defibrillators for ventricular tachycardia and pacemakers for heart block. In end-stage disease, heart transplantation is possible with careful monitoring for parasite reactivation.

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