Thanks to decades of successful vector control strategies, vector-borne transmission of Chagas disease has significantly decreased in many regions. Oral ingestion of Trypanosoma cruzi through contaminated food and beverages, however, is increasing. Unlike vector transmission, oral transmission of Chagas disease entails high lethality in pediatric and adult populations.
“The oral transmission of Chagas disease is becoming a much more recognized route, and it is crucial to understand that people can die from this type of transmission,” Norman L. Beatty, MD, assistant professor of infectious diseases and global medicine at the University of Florida College of Medicine in Gainesville, Florida, told this news organization. Dr. Beatty is the lead author of a recent article on the subject.
In regions where the parasite circulates in the environment, people are consuming foods, fruit juices, and possibly wild animal meat that may be contaminated. “As we experience changes in our environment and in the way we consume food, it is crucial to consider how food preparation is carried out in areas where T cruzi transmission occurs in the environment,” said Dr. Beatty. “And as organic farming methods without insecticides become increasingly common, more research is needed in these areas, both in Latin America and in the United States, to understand if oral transmission of T cruzi is occurring.”
In the Amazon basin, foodborne transmission is already the leading cause of acute Chagas disease. It has been described in Argentina, Bolivia, Brazil, Colombia, Ecuador, French Guiana, and Venezuela.
Dr. Beatty’s colleagues recently treated a Brazilian patient at the hospital in Florida. “He came to our hospital very ill, with acute myocarditis after consuming contaminated açaí.” Clarifying that there is widespread awareness about oral transmission in Brazil, he stated, “We are concerned that it may not be recognized in other areas of Latin America.”
Mexico and regions of Central America have little to no information on oral transmission, but it is likely occurring, and cases may be going undetected in the region, said Dr. Beatty.
He investigated the issue in Colombia as part of an international collaboration involving the University of Antioquia, aiming to find ways to mitigate oral transmission and create a model that can be used throughout Latin America and the United States. For the Colombia study, they reviewed all cases reported to the Ministry of Health and Social Protection, and oral transmission turned out to be more common than the research group expected. “Still, I imagine that in certain areas with limited resources…there are many more cases that are not being reported.
“A myth I would like to dispel is that Chagas disease is not being transmitted in the United States,” Dr. Beatty added. He mentioned that at least 30 American states have vectors, and in Florida, it was documented that triatomines invaded homes and bit residents. In addition, 30% of these insects are infected with T cruzi. Research is underway to determine whether Floridians are becoming infected and if they are also at risk of contracting Chagas disease orally, said Dr. Beatty. “In the United States, we know very little about how many people are infected and what the infection routes are. Much more research is needed.”
Roberto Chuit, MD, PhD, a doctor in public health and an external consultant for the Pan American Health Organization (PAHO), agreed that this route of food contamination, which occurs because of vector-borne parasites, was until recently masked or hidden by the predominance of vector presence. Just as it began to gain importance as other transmission routes were controlled, “it now has extremely high importance in the Americas, as does vertical transmission,” he said.
In 2023, more than 50 years after the first description of oral transmission, the PAHO expert meeting proposed to alert health services and the broader community about the severity and potential lethality of oral Chagas disease outbreaks to elicit immediate responses and mitigation measures. The body also proposed conducting studies to provide detailed information on the contamination source and the wild vectors present in oral transmission foci.