August 28, 2025 Author : Saraiva da Cunha (infectious diseases ) Chagas disease, or American trypanosomiasis, is an infection caused by the parasite Trypanosoma cruzi . At the beginning of the 20 th century, the Brazilian researcher Carlos Chagas identified this parasite, its transmission vector (an insect), and the first cases of the disease that bears his name. It is estimated that Trypanosoma cruzi currently infects worldwide about 7 million people, causing more than 10 thousands deaths per year. Most infected people live in Central and South American countries, where the disease is endemic. Traditionally, Chagas disease was associated with poorer populations and rural areas. However, it can occur in anyone, particularly in endemic areas, and is also present in urban areas. In recent decades, Chagas disease has become increasingly prevalent in non-endemic regions , including the United States, where an estimated 280,000 people are infected. In Europe, Chagas disease is not routinely monitored, but there have been reports of an increase in the number of cases over the last 15 years. Chagas disease is transmitted and progresses silently and, therefore, is often underdiagnosed. It is, however, a significant threat; Most people (estimate of 90%) are unaware of their infection, and a significant percentage will develop late, serious, and irreversible complications later in life, primarily heart failure, arrhythmias, and sudden death. Transmission of Chagas disease Trypanosoma cruzi infection occurs primarily through contact with the feces and urine of insects of the Triatoma genus . These triatomines are also known as kissing bugs because they bite people's faces while they sleep, as they are active at night. They live both outdoors and indoors. Here, they hide in the cracks and crevices of house walls and roofs , as well as in warehouses, kennels, and other animal shelters or nests. Triatomine bugs are not native in Portugal or other European countries, nor are they related to bedbugs (the latter belong to the Cimex genus). When infected, kissing bugs bite human skin to feed on blood, and leave feces and urine near the bite . Rubbing or scratching the bite area spreads the feces and urine, and infection occurs through wounds or cracks in the skin, or through the ocular or oral mucosa. Although this is the main form of Trypanosoma cruzi transmission in regions where the disease is endemic and triatomine bugs are present, other possible transmission routes include : From mother to child during pregnancy or childbirth; Through contaminated blood transfusions or organ transplants; Through consumption of food contaminated with feces from infected insects (common in the Amazon region); In laboratory accidents. In Europe, there are no records of Trypanosoma cruzi infection through its vector, but there are increasing numbers of imported cases, especially in Latin American populations, which is a concern, especially because of transmission during pregnancy and childbirth. Symptoms, diagnosis, and treatment Chagas disease has two phases. About two months after infection, an acute, sudden phase may occur , usually asymptomatic or with mild and mostly nonspecific symptoms, which may persist for weeks or months. These symptoms include: Fever; Headache; Fatigue and muscle aches; Swelling and redness at the site of the bite (called chagoma), which may occur on the eyelids, which turn purple. In this case, it is called Romaña's sign, which is considered a characteristic sign. After years, even decades , in people who have not been diagnosed and treated, chronic infection primarily affects the heart and digestive muscles, causing: In about 30% of those infected: cardiac complications, such as arrhythmias, heart failure, and the risk of sudden death. In about 10% of those infected: digestive disorders, such as megaesophagus and megacolon, difficulty swallowing, constipation, and abdominal pain. Chagas disease is curable when treated in its early stages . Treatment is with antiparasitic medications, which are more effective at eliminating the parasite if administered after infection. In the chronic phase, they can slow the progression of the disease and prevent transmission during pregnancy, but they generally do not completely eliminate the parasite. In addition to treatment aimed at eliminating the parasite and necessary supportive measures, people who develop complications will require specific treatments to control them, whenever possible. Chagas disease prevention There are no vaccines to prevent Chagas disease. Prevention measures that are especially important in endemic and low-resource areas include: Improving housing conditions to prevent the presence of transmitting insects; Using specific insecticides for both personal and environmental use; Screening for infection and treating women of childbearing age, their children, and their siblings; Testing blood and organs intended for transfusions and transplants for Trypanosoma cruzi . In Portugal In 2020, it was estimated that there were approximately 900 people infected with Trypanosoma cruzi in Portugal, the majority of whom were Brazilian migrants. Since 2015, the Portuguese Institute do Sangue e Transplantação has been screening donors who may be at risk of infection. In 2022, two positive cases were detected in donors in the northern region of the country. Sources Gonzalez-Sanz M, Crespillo-Andújar C, Chamorro-Tojeiro S, et al. Chagas disease in Europe. Trop Med Infect Dis 2023;8:513. Instituto de Higiene e Medicine Tropical. Dia Mundial: Em Portugal, cerca de 900 pessoas vivem com a doença de Chagas e a maioria não sabe. 2020. U.S. Center for Disease Control and Prevention. Chagas disease . World Health Organization. Chagas disease (also known as American trypanosomiasis) . Meet the infectious diseases clinical team from Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
