Income inequality turns "neglected tropic diseases" into American diseases of "the poor living among the wealthy"

The deadly infectious diseases that were eradicated in America during the 20th century are now roaring back, thanks to growing poverty, failing sanitation, and underinvestment in science and health research and regulation.

Chagas, hookworm disease, cysticercosis, and chikungunya — just to name a few. They cluster in the American south and southwest, and disproportionately effect the poorest Americans, who are usually also the brownest Americans.

In 2014, Baylor tropical medicine physician Rojelio Mejia travelled to Montgomery to test his suspicion that hookworm remained a significant problem. He wanted to recruit 100 people for a small pilot study that would test them for hookworm and provide treatment where needed. His first trip netted just 11 participants.

"They have a lot of mistrust of a tall, bald white man coming to see them," he says.

Partnering with a local civic organisation and church led to more volunteers, and his final study had 56 participants. Mejia and colleagues also went to the volunteers' homes to sample the environment. In contrast to the urban poverty of Houston's Fifth Ward, these were poor rural areas. The region's fertile black soils can't filter waste effectively, but most residents can't afford the expensive septic systems required to solve the problem cleanly. Instead, they simply buy as much pipe as they can afford and run it from their toilet to the back of their yards, where the waste collects. The hilly terrain means that rain and flooding spread the waste over the ground – perfect conditions for spreading hookworm. Mejia has now finished collecting samples, but he hasn't yet finished his analysis.

Mejia and Hotez believe that parasitic infections like hookworm contribute to a vicious cycle of poverty. Hotez points to a little-known parasitic disease called toxocariasis (caused by roundworm) as another example: he estimates it infects 2.8 million African Americans, most of them living in urban poverty. The disease can cause asthma and wheezing, as well as cognitive delays and behaviour problems. In 2014, Hotez proposed that some of the educational and economic disparities experienced by poor African Americans might be partially due to toxocariasis. These difficulties, in turn, make it harder for people to find steady employment and well-paying jobs as adults. This means their children are also likely to grow up poor, continuing the cycle for another generation.

Why Are We Letting Infectious Diseases Make A Comeback? [Carrie Arnold/Mosaic]