Which Family Members Need Chagas Disease Screening?

If you or a family member has been diagnosed with Chagas disease, certain close relatives should be tested as well. Because Chagas disease can be passed from mother to child during pregnancy or acquired through shared exposure to the insect vector in countries where the disease is common, screening helps identify the infection early so it can be effectively treated before any long-term complications arise.

In non-endemic countries (areas where the disease is not naturally spread by the kissing bug, such as the United States or Europe), clinical guidelines focus on screening close blood relatives and individuals who shared the same living conditions in a region where Chagas is common.

Blood Relatives Who Should Be Tested

Children of an infected mother
If a woman is diagnosed with Chagas disease, all of her biological children should be tested ^[1]. Chagas disease can be transmitted during pregnancy, which is known as congenital transmission ^[2][3]. Please remember that fathers cannot pass Chagas disease to their children biologically; this type of transmission only occurs from mother to child.

Testing children is crucial because they often have no symptoms. It is completely normal to feel anxious about this, but discovering a positive diagnosis now is a good thing: early treatment is highly effective and cures the infection long before serious heart or digestive issues have time to develop ^[2][4][3]. The type of test depends on the child’s age:

• Newborns: If a pregnant woman tests positive, her baby will be tested at birth using molecular tests like polymerase chain reaction (PCR), which look for the parasite’s DNA ^[5][6].
• Older infants: Because antibodies from the mother can remain in the baby’s blood for months, infants who initially test negative may need a follow-up serological test (a blood test checking for the immune system’s response to the parasite) at 9 to 10 months of age to confirm they are clear of the infection ^[7][5][6].
• Older children and teenagers: Children over 10 months of age are tested exactly like adults, using standard serological blood tests ^[5][8].

Siblings and Mothers
If someone is diagnosed with Chagas disease, their biological mother should ideally be tested to determine if the infection was passed on during pregnancy ^[1][9]. If the mother tests positive, all of her other biological children (the infected person’s siblings) must also be screened, as they carry the same risk of congenital infection ^[10][11]. If the mother is deceased or unavailable for testing, siblings should go ahead and get screened directly.

Spouses, Partners, and Household Members

Spouses and people who shared a home in an endemic area
If you lived in an endemic region (such as parts of Mexico, Central America, or South America) where the triatomine bug is found, anyone who lived in the same household with you during that time should be screened ^[12][9][13]. This includes spouses, adopted siblings, or extended family who shared the same environmental exposure to the insect vector.

Spouses and sexual partners who met in non-endemic areas
If you met your spouse or partner in a non-endemic area (like the US or Europe) and they never lived in an endemic region, current public health guidelines do not recommend they undergo routine screening ^[14][1]. While research has noted rare instances of sexual transmission, it is not considered a primary way the disease spreads.

How Screening is Done

For adults and older children, screening involves a simple serological blood test (a test that looks for antibodies in your blood) ^[5][8]. To ensure an accurate diagnosis and prevent false positives caused by cross-reactivity with other parasitic infections, medical guidelines from organizations like the Pan American Health Organization (PAHO) and the World Health Organization (WHO) require using at least two different types of serological tests to confirm a chronic Chagas infection ^[7][15][16].

If any of your family members test positive, it is important they speak with their doctor about starting treatment. Additionally, anyone who tests positive for Chagas disease should permanently refrain from donating blood, organs, or tissues to prevent passing the infection to others.