Chagas disease

Infection caused by a parasite, the "Trypanosoma cruzi", which is transmitted through the bite of an insect. Less often, it can also be transmitted by ingesting contaminated food, blood transfusions, transplanting infected organs or across the placenta from an infected mother to her fetus.

The contaminated insect bites a person or animal, depositing parasites that pass through the wound of the bite or mucous membranes. These mature, multiply and pass into the bloodstream from where they infect other parts of the body (usually heart, digestive system and nervous system) producing the symptoms of infection.

It is estimated that 8 million people in the world are infected, being more frequent in South or Central America, Mexico and the US.

The disease manifests itself in several stages. In the acute phase, the area of ​​the bite (known as "chagoma" or "sign of Romaña" if it affects the conjunctiva) can be inflamed and is accompanied by general malaise, fever and an increase in the size of the lymph nodes, liver and spleen. The symptoms usually disappear without treatment. More severe cases may present inflammation of the heart or meningoencephalitis. Afterwards, the patient enters a phase, which can last for years, in which the parasite remains in the body but without causing symptoms (latency). 20-40% develop a chronic disease with involvement of the heart (dilation, insufficiency, arrhythmia), digestive tract (dilation of the esophagus or bowels) or nervous system (dementia).

The diagnosis is reached by detecting the parasites by examining a sample of blood or tissue under an optical microscope. Other tests such as serology or PCR can also be performed.

The treatment is based on antiparasitic drugs: benzonidazole or nifurtimox (before reaching the chronic phase) and support measures if complications appear. Prevention is important, by trying to improve the quality and hygiene of human dwellings and domestic animals.