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Chagas' disease can remain hidden because infections remain asymptomatic for decades. The parasites slowly invade heart tissue, causing potentially lethal heart disorders in a third of all people infected. If physicians diagnose an infection early, they can cure it with drugs.
In July, Melissa Nolan Garcia, an epidemiologist at the National School of Tropical Medicine, enrolled Wright and 30 other Texans who similarly learned of their diagnoses through blood drives in a study to assess their heart function and to fill out the profile of a Texan at risk for Chagas'. For example, did many of the people diagnosed hunt or golf in regions where the bug lives?
Researchers in Houston would like to screen people proactively, as opposed to relying on results from blood drives, but budgets for surveillance are tight. Right now, the Centers for Disease Control and Prevention counts 300,000 cases of Chagas' in the U.S., but they acknowledge that the number falls short. "We might hear about individual patients, but that would be a huge underestimate of what's out there," says Monica Parise, chief of the parasitic disease branch at the CDC. The government shutdown has further curtailed the agency's efforts: 70 percent of its staff has been sent home.
Dengue fever outbreaks among locals in Brownsville, Texas, piqued the interest of Kristy Murray, an infectious disease specialist at the National School of Tropical Medicine. Murray has traveled to poor, remote villages in southeast Asia to track outbreaks, but she has discovered plenty of mysteries to keep her occupied back in her home state.
The disease, which is spread by mosquitoes, diminished with mosquito control efforts in the early and mid-1900s, as houses were built with better screens, swamps were drained and insecticides dumped across mosquito-ridden regions. A dengue infection causes acute fevers, headaches, back pain and, on rare occasions, death. The risk of death skyrockets if a person is reinfected with another dengue strain.
Feverish patients often leave the hospital without a diagnosis, so Murray decided to revisit blood and spinal fluid samples drawn from these cases in Houston between 2003 and 2005. Nearly 50 samples tested positive for dengue. Most patients presumably recovered from the fever. However, one patient — a 92-year-old woman — died of brain inflammation, the disease's hallmark.
The deceased woman, as well as several others who tested positive, had not left Houston for at least two years before they had the samples taken, indicating that they caught the dengue virus locally. Murray points to a graph in a report showing when the cases occurred. They peak in mid-2003, suggesting that a dengue outbreak might have slipped completely below the radar. What worries her most is that alternative strains in Mexico or Florida could feasibly make it to Texas if an infected person traveled between the two places. "We need to be on guard," she says. "Our biggest bang for the buck would be to focus on dengue with physicians, so that they know how to recognize a case and submit samples for testing."
Murray has watched outbreaks unfold in the U.S. before. In 1999, she was part of the CDC team that discovered crows dropping dead from West Nile virus in New York City. At that time, the virus had never before been seen in the Western Hemisphere. Since then, more than 1,500 Americans have died from West Nile infections.
"The lesson from West Nile is that we should really be looking for diseases that we think are outside of our border," Murray says, adding that detection costs money. "Public health departments have been shrinking because they don’t have the budgets they used to," she says. "With a limited workforce, they focus on disasters as they happen, instead of what might be a problem in the near future."
Umair Shah feels this pressure acutely as director of the Harris County Public Health department, which provides services for 4.1 million people living in Houston and the surrounding areas. He has heard of cases of murine typhus, Chagas' and dengue, but he does not have the resources to intensify surveillance. Since 2010, he says, the department has reduced its staff by 30 percent because of budget cuts.
"The public expects you to just figure it out and be as effective with fewer people," he says, "but that’s a real challenge." Shah says people may have forgotten about the measures that enabled Texas to curb several diseases half a century ago. "A doctor can say, I treated a child who had cancer, and there’s obvious value in that," he says. "But who is the poster child when you prevent a disease in the first place?"
At the National School of Tropical Medicine’s clinic, doctors teach their colleagues how to recognize neglected diseases that are skipped over in medical school. One Friday morning, a clinician shadows a tropical disease doctor as she treats a Cuban patient for leishmaniasis, a parasitic disease that has caused open sores to form on her face. Before the lesson, the young clinician says, she would have wrongly diagnosed the infection as Staphylococcus.
Baylor College of Medicine and Texas Children’s Hospital supported Hotez’ vision for a national school with a 10-year, $20 million start-up package, in hopes of becoming a resource for doctors, scientists and patients across the U.S. The school also houses high-tech laboratories for research into vaccines for neglected diseases that would save lives on a global scale. Finally, Hotez, who left Washington, D.C., for Houston two years ago, has added one final mission for his school: advocacy. He frequently hops on flights to Washington, D.C., where he promotes the message that the United States ignores neglected diseases at its own peril.
If neglected diseases turn out to be as prevalent as Hotez suspects, government agencies might put more money toward surveillance, education and research in the coming years. For now, the scientists in Houston and Galveston are taking the first steps. "Infectious disease programs focus on developing countries instead of pockets of poverty here in the U.S.," says Hotez. "That's where we come in."