Researchers urge for U.S. recognition of Chagas as endemic

Researchers from Texas A&M University, the University of Florida and the Texas Department of State Health Services say the time is now to recognize Chagas disease as endemic in the U.S. The multi-institutional team’s perspective article, published in the Centers for Disease Control and Prevention’s September volume of Emerging Infectious Diseases, underscores growing evidence that points to endemic transmission.

“The biggest need is awareness, and that is the focus of our publication to share the scientific perspective that Chagas disease is endemic in the U.S.,” said Gabriel Hamer, Ph.D., Texas A&M AgriLife Research entomologist in the Department of Entomology, Bryan-College Station. “Too often, medical and veterinary training programs dismiss Chagas as only a tropical disease and irrelevant to public and animal health in the U.S.

“But kissing bug vectors, the parasite and locally acquired human cases are here. It is critical for our next generation of doctors and veterinarians to be aware of this vector-borne disease to assist with the diagnosis of humans and animal patients.”

Raising awareness about U.S. Chagas cases, endemicity

Blood-sucking triatomines, commonly known as kissing bugs, are confirmed in thirty-two U.S. states. Many carry the protozoan parasite Trypanosoma cruzi, also known as T. cruzi, which causes Chagas disease. Each infected bug poses a risk of transmission to humans and companion animals. Eight states in the southern U.S. have documented human T. cruzi infections, and therefore, locally acquired Chagas disease. Texas leads the nation in the number of locally acquired Chagas disease cases.

Norman L. Beatty, M.D., FACP, associate professor of medicine at the University of Florida College of Medicine, said that public awareness could lead to earlier diagnosis and timely treatment. He said the endemic status of Chagas disease will raise awareness among local, state and federal public health agencies.

“Identifying Chagas disease as an endemic disease in the United States ensures that the public understands this parasite is being consistently transmitted in certain regions of our country,” Beatty said. “The concern with Chagas is that it goes unrecognized for decades until symptoms appear, and often, chronic damage is done. Early detection can lead to treatment, which could be curative and ongoing monitoring for disease progression.”

Why classification matters

The Centers for Disease Control and Prevention define “endemic” as the constant presence or usual prevalence of a disease or infectious agent in a population within a geographic area. Beatty, Hamer and other members of the research team implore that the reclassification of Chagas from nonendemic to endemic is critical to improving awareness, diagnosis and surveillance.

Co-author Sarah Hamer, Ph.D., DVM, DACVPM, professor of epidemiology in the Texas A&M University College of Veterinary Medicine and Biomedical Sciences, said many wildlife species are involved in the ecology of Chagas disease. Animals provide blood meals to kissing bugs and serve as parasite reservoirs that pose a threat to people and pets.

“These wildlife-associated bugs occasionally disperse to areas where dogs and humans are at risk of infection,” she said. “It takes a ‘one health’ approach to decode the complex transmission cycles. But general awareness about the disease’s presence here and how it is transmitted is a necessary first step toward prevention.”

Gabriel Hamer said Chagas disease’s inaccurate classification downplays the risk it poses in the U.S. and creates a false sense of security among people and public health officials.

“The reality is the vectors are here, the parasite is here, and infections do occur,” he said. “Public health messaging should reflect the science so communities and professionals can respond appropriately.”