How is it transmitted?

Chagas disease can be transmitted in five different ways:

  • by a vector (through insect faeces)
  • vertical or congenital (from mother to her child during pregnancy)
  • blood transfusions and organ transplants
  • oral
  • accidental laboratory exposure

Vector-Borne Transmission

The most common mode of transmission for Chagas disease is infection contracted from the faeces of an insect vector. The usual English name of the bloodsucking vector is the kissing bug, but it has many different names in different places: vinchuca, chinche, chipo, pito, barbeiro and chichá guazu, among others.

After the insect bites a person and feeds on their blood, it usually defecates close to the bite. The parasite, which is present in the faeces deposited on the skin, enters the host’s bloodstream through an opening in the skin when the person scratches the itchy bite. This is known as vector-borne transmission. Occasionally the parasite can enter through mucosal tissue, if the faeces are deposited close to the eyes or mouth, for example.

Vertical Transmission

Another fairly common mode of transmission is from mother to child. A child carried by pregnant woman who has Chagas disease can become infected during pregnancy or childbirth. This type of transmission can also occur outside the areas where the disease is endemic. Consequently, all the children of a woman diagnosed with Chagas disease must be tested even if they were born outside of Latin America. Nevertheless, infection with Chagas disease is not an obstacle to a normal pregnancy and it does not mean that a mother cannot breastfeed her child.

Blood Transfusions and Organ Transplants

A person who receives a transfusion of blood (or blood products) or an organ transplant obtained from an infected person may get Chagas disease.

Today, screening mechanisms to prevent transmission of the disease are being established in blood banks and included in organ donation procedures, but the implementation of these measures is taking longer in some countries.

Oral Transmission

It is also possible to contract Chagas disease by ingesting food or drinks that have been contaminated with the parasite. Oral transmission is less common than other forms and occurs only in areas where the vector is found. For instance, there have been reports of cases of Chagas disease caused by contaminated juice made from acai fruit, sugar cane or guava.

Accidental Laboratory Exposure

Professionals who handle samples containing the parasite or who work directly with the insect vector can accidentally get the disease if they are bitten or inoculated through a mucous membrane. This form of transmission is very rare.