Anyone infected with the Trypanosoma cruzi parasite is considered to have Chagas disease even if they never develop symptoms. In seven out of ten cases, the parasite causes no damage so that the fact that someone is "infected" does not always mean that he or she will develop symptomatic disease.

Among those who do develop symptoms due to Chagas disease, the most common problems are:

• heart problems, which occur in about 3 out of every 10 people infected;
• digestive disorders, which occur in 1 or 2 out of every 10 people infected.

When the heart or digestive tract are affected, the most common symptoms are:

• dizziness
• fainting spells
• palpitations
• chest pain
• fatigue
• constipation
• difficulty swallowing

Most children and adults who have Chagas disease do not know when they were infected and live their whole lives with the parasite without experiencing any symptoms.