Chagas disease
Symptoms, transmission, and current treatments for Chagas disease
Chagas disease
Symptoms, transmission, and current treatments for Chagas disease
What is Chagas disease?
Chagas disease, also known as American trypanosomiasis, is a potentially life-threatening disease caused by the parasite Trypanosoma cruzi. It is most commonly transmitted by biting insects known as ‘kissing bugs’ that are infected with the parasite. It can also be passed from mother to child during pregnancy and childbirth. As people typically show no symptoms for many years, most are unaware they have Chagas.
Up to a third of people with Chagas will suffer heart damage that becomes evident only many years later and can lead to progressive heart failure or sudden death. Chagas kills more people in Latin America each year than any other parasitic disease, including malaria.
What is the impact of Chagas disease?
- Over 7 million people estimated to have Chagas in the world
- Over 100 million people at risk
- 30,000-40,000 new cases per year
- Over 10,000 deaths per year
- Over 1 million women of childbearing potential living with Chagas
- Less than 10% of those infected have been diagnosed
- Endemic in 21 countries across Latin America
- Also present in North America, Europe, Japan, and Australia
ENDEMIC IN 21 LATIN AMERICAN COUNTRIES
What are current treatments for Chagas disease?
The two current treatments, benznidazole and nifurtimox, were both discovered half a century ago.
They are effective against the disease if given soon after infection and appear to be effective in the chronic asymptomatic phase of the disease. However, they have significant drawbacks, including:
- long treatment periods (60-90 days)
- serious side effects
- a high drop-out rate of patients due to side effects
- they have not been proven effective in people with severe chronic symptoms
To improve treatment in the short and medium-term, we are investigating new regimens of benznidazole to reduce side effects, and, together with partners, we helped develop the first formulation of benznidazole specifically for children.
What new treatments for Chagas disease are needed?
Chagas disease has been targeted by the World Health Organization (WHO) for elimination but fewer than 10% of people with Chagas have been diagnosed and even fewer have been treated. To eliminate the disease, we need new drugs for both the chronic indeterminate and chronic advanced stages of the disease that are safe, effective, and field-adapted. We also need to improve access to treatment and diagnosis for all people who are affected – including in remote or rural areas.
What Chagas disease medicines are we working on?
We aim to deliver safer, more effective, and more affordable treatments for people affected by Chagas disease. We are also working to improve access to diagnosis and treatment using existing tools and develop better tests to monitor response to treatment.
Find out about our work developing treatments for Chagas disease
How do you get Chagas disease?
- Insect bites: triatomine bugs, commonly known as kissing bugs, transmit the T. cruzi parasites by biting people and defecating or urinating close by; the parasites enter the body when people unintentionally scratch the area, allowing the parasites in the faeces or urine to enter the bite
- Mother-to-child: can be passed from mother to child during pregnancy or childbirth
- Blood transfusion or organ transplant: this type of transmission has decreased in the last decade because of improved control in blood banks and hospitals
- Food: eating food contaminated with infected kissing bugs or their faeces
What are the symptoms of Chagas disease?
The disease has two clinical phases:
Acute phase:
- Lasts for about 2-8 weeks after infection
- Can occasionally cause severe symptoms or deaths, especially in infants
- In most cases, symptoms are absent or mild and unspecific
- Possible skin lesions or a purplish swelling of the eyelids
- Possible fever, headache, enlarged lymph glands, pallor, muscle pain, difficulty in breathing, swelling, and abdominal or chest pain
Chronic phase, which can be divided into two stages:
- The chronic, indeterminate stage is when people have no symptoms. This stage lasts for the rest of the infected person’s life unless they are treated. During this stage, the parasite is hidden deep in organ tissue (especially the heart).
- The advanced chronic stage is when 30-40% of people with Chagas experience symptoms. This stage develops years after infection and most often results in damage to the heart, while others may experience abnormal enlargement of the colon or esophagus.
- People in both chronic stages are at risk for severe symptoms if their immune system is suppressed due to medical treatment or other conditions such as HIV.
How is Chagas disease diagnosed?
Suspected cases of acute Chagas are usually confirmed by detecting parasites in the blood through a microscope, or by conducting laboratory tests or using rapid tests to detect antibodies to the parasite. Because the parasite can be difficult to
detect in the chronic phase, two or three different tests may be used to
confirm Chagas disease. Once treatment has been completed, even if it has been
successful, it can take many years before standard diagnostic tests show as negative. Better tests to monitor treatment progress are urgently needed.
Find out about our work on biomarkers.
More information
Last updated September 2025
The Children of the Sierra
In Sierra Nevada de Santa Marta mountains of northern Colombia, the Indigenous Wiwa people live with some of the highest rates of Chagas disease in the world. Our film shows how partnering with local leaders and valuing traditional knowledge can help eliminate Chagas in very remote communities.
Making medical history for neglected patients
We develop urgently needed treatments for neglected patients and ensure they’re affordable, available, and adapted to the communities who need them
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