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Neglected tropical diseases in the US--the link to poverty

Opinion piece "Tropical Diseases: The New Plague of Poverty"
By PETER J. HOTEZ Published: August 18, 2012 New York Times

Houston

IN the United States, 2.8 million children are living in households with incomes of less than $2 per person per day, a benchmark more often applied to developing countries. An additional 20 million Americans live in extreme poverty. In the Gulf Coast states of Louisiana, Mississippi and Alabama, poverty rates are near 20 percent. In some of the poorer counties of Texas, where I live, rates often approach 30 percent. In these places, the Gini coefficient, a measure of inequality, ranks as high as in some sub-Saharan African countries.

Poverty takes many tolls, but in the United States, one of the most tragic has been its tight link with a group of infections known as the neglected tropical diseases, which we ordinarily think of as confined to developing countries.

Outbreaks of dengue fever, a mosquito-transmitted viral infection that is endemic to Mexico and Central America, have been reported in South Texas. Then there is cysticercosis, a parasitic infection caused by a larval pork tapeworm that leads to seizures and epilepsy; toxocariasis, another parasitic infection that causes asthma and neurological problems; cutaneous leishmaniasis, a disfiguring skin infection transmitted by sand flies; and murine typhus, a bacterial infection transmitted by fleas and often linked to rodent infestations.

Among the more frightening is Chagas disease. Transmitted by a "kissing bug" that resembles a cockroach but with the ability to feed on human blood, it is a leading cause of heart failure and sudden death throughout Latin America. It is an especially virulent scourge among pregnant women, who can pass the disease on to their babies. Just last month, the first case of congenital Chagas disease in the United States was reported.

These are, most likely, the most important diseases you've never heard of.

They disproportionately affect Americans living in poverty, and especially minorities, including up to 2.8 million African-Americans with toxocariasis and 300,000 or more people, mostly Hispanic Americans, with Chagas disease. The neglected tropical diseases thrive in the poorer South's warm climate, especially in areas where people live in dilapidated housing or can't afford air-conditioning and sleep with the windows open to disease-transmitting insects. They thrive wherever there is poor street drainage, plumbing, sanitation and garbage collection, and in areas with neglected swimming pools.

Most troubling of all, they can even increase the levels of poverty in these areas by slowing the growth and intellectual development of children and impeding productivity in the work force. They are the forgotten diseases of forgotten people, and Texas is emerging as an epicenter.

A key impediment to eliminating neglected tropical diseases in the United States is that they frequently go unrecognized because the disenfranchised people they afflict do not or cannot seek out health care. Even when there is a clinic or community health center in an impoverished area, it often lacks the necessary diagnostic tests, and the staff is rarely trained to recognize and manage neglected tropical diseases.

We have an opportunity to stop these diseases, but we need to act. First, we need programs of active surveillance and monitoring to obtain more accurate information on the true prevalence of these diseases and how they are transmitted. We also need better diagnostic tests; worm infections like cysticercosis and toxocariasis can often be treated effectively with antiparasitics and anti-inflammatories, but they are frequently misdiagnosed.

Finally, we need safer and more effective drugs and new licensed vaccines. For instance, there are drugs to treat Chagas disease, like benznidazole and nifurtimox, but they are hard to procure, often not effective in adults after the symptoms of heart disease begin and so toxic they cannot be taken by pregnant women. And unfortunately, with a few exceptions -- like some promising new dengue vaccines under development -- the major pharmaceutical companies see little financial advantage in investing in better treatments or vaccines for these diseases.

With the looming possibility of budget cuts to the Centers for Disease Control and Prevention and its excellent Parasitic Disease Branch, others will need to step up. Texas and the Gulf Coast are home to some of the country's greatest universities and medical schools, and they can bring considerable brainpower to bear on this problem.

In Houston, the Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development have organized a research unit to develop new vaccines and diagnostics. And Baylor College of Medicine created a new tropical medicine school to teach doctors and other health care providers to recognize, diagnose and treat these infections. A key component is a tropical disease clinic outside Houston where patients show up every Friday. On recent Friday mornings just over the last month, the clinic's director has treated a young woman with cutaneous leishmaniasis, three people with brain lesions from cysticercosis and a middle-aged man with Chagas disease.

While immigration is sometimes blamed for introducing neglected tropical diseases into the United States, the real issue is that they are now, to varying degrees, also being transmitted within our borders. Without new interventions, they are here to stay and destined to trap people in poverty for decades to come. Fifty years ago, Michael Harrington's book "The Other America: Poverty in the United States" became a national best seller. Today more people than ever before live in poverty in this country. We must now turn our attention to the diseases of this Other America.

Peter J. Hotez is the dean of the National School of Tropical Medicine at Baylor College of Medicine and the president and director of the Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development.

A version of this op-ed appeared in print on August 19, 2012, on page SR4 of the New York edition with the headline: Tropical Diseases: The New Plague of Poverty.

Dengue fever has been reported in parts of South Texas like Brownsville.

http://www.nytimes.com/2012/08/19/opinion/sunday/tropical-diseases-the-new-plague-of-poverty.html

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