Marshallese residents of Ebeye face the health threats of both the “developing” and industrialized worlds. Infectious diseases like tuberculosis, even cholera, flourish due to poverty, malnutrition, overcrowded housing, and squalid living conditions, including water shortages, power outages, and poor sanitation. Lack of economic opportunities and healthy food options, combined with the chronic stressors of poverty, dislocation, and cultural loss, also contributes to staggering levels of “modern” illnesses like diabetes, heart disease, hypertension, obesity, cancer, and suicide.

Tuberculosis provides a revealing case study of how poverty can get “under the skin” and render bodies more susceptible to illness. Public health experts estimate that one third of the earth’s population, about two billion people, are infected by the bacterium that causes TB. But most of those people will never become sick; their immune systems will hold the disease in check.

However, about nine million people each year do become sick with the potentially deadly lung ailment, usually because they live in conditions of poverty that compromise their immune systems and undermine their bodies’ ability to fight off the disease.

According to Dr. Jim Yong Kim, co-founder of Partners in Health, a leader of world efforts to eliminate TB, “What tuberculosis needs to flourish in a person’s body is a broken down immune system. So just the stress itself of poverty can contribute to the likelihood of developing active tuberculosis… And there’s nothing like malnourishment to decrease the immune response enough to let tuberculosis flourish.”

Conversely, improved living conditions can help protect communities against TB. At the turn of the 20th century, tuberculosis was the leading killer in many U.S. cities. But TB rates fell by 70% between 1900 and 1940, before antibiotics to treat the disease were invented. What made the difference?

Better housing and sanitation codes, along with social changes – like the eight hour workday, collective bargaining, social security, and universal high school – that enabled more people to share in the nation’s growing wealth. People’s improved standards of living strengthened their bodies’ immune systems. In fact, Richard Hofrichter, senior policy analyst for the National Association of County and City Health Officials (NACCHO), refers to social and economic policies that improve people’s living conditions and participation in political decisions as our “social immune system.”

Living conditions on Ebeye are ideal for the spread of tuberculosis. TB rates on the island are 220 per 100,000 people (compared to 4 per 100,000 in the United States). To successfully cure TB in an individual requires that the patient carefully complete a full course of treatment on schedule, taking up to four different drugs each day for six months. If patients fail to complete their drug regimen, the TB bacillus can mutate and the disease can return in a multiple-drug-resistant form (MDR-TB) – far more dangerous. Every day, public health workers drive the streets of Ebeye tracking their patients to ensure that they complete their course of medications.