This week as President Obama asks Congress to provide $2 billion to help control an influx of Central American children crossing the South Texas border, many are voicing a prominent concern that children entering from Guatemala, El Salvador, and Honduras will introduce infectious diseases across the southern United States. Politicians and even some physicians have even labeled these children a threat to homeland security because of their potential to create a public health crisis.
However, the reality of Texas (as well as adjacent areas of the US Gulf Coast) is that tropical infectious diseases are already here and many of them have been here for decades or centuries. Rather than immigration it is the convergence of extreme poverty and warm climate that make this region vulnerable to a group of illnesses known as the neglected tropical diseases or 'NTDs'. Texas and the Gulf Coast states rank among the poorest in our nation, and the pervasive low-quality housing and environmental degradation, together with long, hot, and humid summers create the perfect conditions for NTDs to flourish.
For example, the Aedes aegypti mosquito that transmits a variety of arboviruses such as dengue fever, yellow fever, and Chikungunya has been in Houston and other southern cities for at least a decade, after causing frequent and sometimes catastrophic epidemics in the continental US up until the late 1800s. Houston experienced outbreaks of dengue fever between 2003 and 2005, and continues to be at risk for other arbovirus infections including yellow fever and Chikungunya. Chagas disease is a serious and debilitating heart disease caused by parasitic microorganisms known as trypanosomes and transmitted by kissing bugs.Hundreds of thousands of people live with Chagas disease in the US, and many dogs are also infected. Millions of African Americans living in poverty in the southern US suffer from other parasitic infections such as toxocariasis and trichomoniasis. Additional NTDs in Texas include cysticercosis, murine typhus, West Nile virus infection, and an interesting syndrome of tuberculosis in patients with underlying diabetes.
A key point is that Texas and surrounding regions are vulnerable to NTDs for the same reasons as poorer parts of Mexico and Central America. Indeed in a recent paper in Public Library of Science Neglected Tropical Diseases I listed Texas and Mesoamerica as one of ten "global hotspots" of NTDs, along with areas in sub-Saharan Africa and Southeast Asia. We established our National School of Tropical Medicine in Houston because it is the epicenter of America's NTDs.
For all these reasons, the current wave of Central American children entering the US pose little, if any, added threat in terms of disease. With very few exceptions, if these children have diseases they are ones that previously gained a foothold in the US a long time ago. At least one - Chagas disease - has been detected in prehistoric mummified remains from the Rio Grande Valley.
Perhaps one exception is the fact that many of Central America's children, unlike most US children, live with intestinal worms. We can do something about that by giving them an inexpensive deworming tablet. The only problem is that worm eggs and larvae are so widespread in the soil of Central America that we will need a vaccine to prevent them from becoming reinfected upon returning. Our laboratories are working on that problem, with the hope that one day we can create a pan-anthelminthic vaccine that could benefit children living in poverty everywhere.
NTDs are a major homeland security threat to Texas and the US Gulf Coast. They have been a threat for quite a while and yet our government and government officials have mostly ignored the problem - until now. New legislation, known as the "End Neglected Tropical Diseases Act" (H.R. 4847), was just introduced in the House of Representatives specifically identifies the problems of NTDs in the US. This bill could begin to turn things around for the poorest and most vulnerable people in our nation.
Peter Hotez MD PhD is dean of the National School of Tropical Medicine at Baylor College of Medicine, Texas Children's Hospital Endowed Chair of Tropical Pediatrics, and President of the Sabin Vaccine Institute