You might think think tropical diseases like hookworm and elephantiasis have gone the way of smallpox, which was eradicated about 30 years ago. Or, that they are just obscure problems affecting people in the most remote parts of the developing world.
But several million Americans, mostly immigrants and the poor, have some of these conditions, which are often going unrecognized by American doctors.
For example Chagas disease, a parasitic disease that often causes no symptoms at first but can lead to irreversable heart and esophagus damage, was discovered in eight blood donors in San Antonio in early 2009.
Tropical disease expert, Peter Hotez, president of the Sabin Vaccine Institute, recently noted the prevalence of some of these conditions in a New York Times piece.
In an interview with Shots, Hotez said he spends his days "making vaccines for people who can't afford them." In his research, he kept stumbling across cases of neglected tropical diseases in Americans who had never traveled outside the country.
This prompted him to investigate and write a 2008 journal article providing the first estimates of the number of tropical diseases cases in the U.S. The research identified two dozen infections that are most common among communities in Appalachia, the Mississippi Delta and the American South.
One example is toxocriasis, a parasitic worm infection transmitted by dogs, which could affect up to 3 million people.
These "neglected infections of poverty," as Hotez calls them, disproportionately affect poor minority communities, especially African-Americans and Hispanics.
Few public health programs are actively monitoring these conditions and a limited number of health care providers are trained to even recognize them, he notes.
Los Angeles cardiologist Sheba Meymandi is one of the few doctors specializing in Chagas disease. The disease affects many Latin American immigrants, but it's a mystery to most doctors, even in areas with large susceptible immigrant populations.
"You know, that's not what we're taught in medical school. Chagas is an exotic disease. That's what you're taught. You're not going to see it much here," Meymandi, who heads the first U.S. clinic that focuses on the disease, told PBS' Newshour last year. In its advanced stages, Chagas can cause heart complications.
For now, Hotez says we need to get a better handle on what we’re dealing with. He wants expanded surveillance and research. Last October, he helped organize a national summit to alert policy makers about tropical diseases in this country.