News that a patient infected with the Ebola virus entered the United States and is now hospitalized in Dallas has created fears about a potential epidemic. But as Centers for Disease Control and Prevention Director Tom Frieden told the nation on Tuesday, "I have no doubt that we will stop this in its tracks in the US."
I agree with him.
The Ebola virus is not that easy to transmit from person to person. It requires direct contact with the secretions — saliva, blood, urine — of someone who is already very sick with the virus. Unlike a number of respiratory infections such as influenza, measles, and whooping cough — all of which are highly contagious diseases — persons are not at risk for contracting Ebola unless they are healthcare providers or family members who are not wearing personal protective equipment (PPE).
Equally important, in the United States we have outstanding federal, state, and local health agencies that can aggressively work to identify and isolate those who have come into contact with Ebola patients.
In contrast, Ebola has devastated Liberia and Sierra Leone in West Africa in large part because both countries only recently emerged from horrific civil wars and conflicts that resulted in massive breakdowns in their healthcare infrastructure. As a result, it has not been possible to regularly provide healthcare workers with hospital beds — much less PPE — and facilities in order to appropriately isolate patients, or to identify and isolate people who have been in close contact with patients.
Although we refer to diseases such as Ebola as "tropical diseases," these infections are first and foremost diseases of extreme poverty and of conflict or post-conflict settings. However, thanks to the recent US commitment to provide 3,000 military personnel to West Africa and to help establish healthcare infrastructure, I have some optimism that the Ebola epidemic could be contained in the coming months.
Are there links between toxocariasis and achievement gaps noted among socioeconomically disadvantaged groups?
Putting in place health systems in Guinea, Liberia, and Sierra Leone would also create a mechanism for introducing new drugs and vaccines. I'm very excited about some coming down the pipeline, including the antiviral drug favipiravir and some new vaccines being developed by the US National Institutes of Health and GlaxoSmithKline, along with Crucell and the Canadian Public Health Agency.
But while there won't be Ebola epidemic in the US, I am very concerned about the neglected tropical diseases now affecting the US Gulf Coast. They're widespread, but because they occur predominantly among Americans who live in extreme poverty, very few people know about them.
I estimate that at least 12 million Americans suffer from at least one neglected tropical disease.
Chagas is one example. Caused by a parasitic micro-organism known as a trypanosome that lives in heart tissue and can be transmitted by the kissing bug, Chagas affects an estimated 300,000 Americans. In the end stages of the disease, the parasite causes cardiomyopathy, in which the heart enlarges and fails to pump blood; this is associated with a high mortality rate and sudden death. We are finding lots of cases here in Texas, many among people who have not traveled abroad. A high percentage of dogs are infected, and we have recently reported that Chagas might affect hunters and campers in particular.
Two parasitic worm infections found widely in the US affect the brain. One is cysticercosis, which has emerged as a significant cause of epilepsy. The other is toxocariasis, which is transmitted from worm eggs shed by dogs and cats in their feces; the disease is prevalent in impoverished and environmentally degraded areas where stray dogs and cats are common. African American children living in poverty are disproportionately affected, and suffer from intellectual and cognitive deficits as a result. A question to consider: Are there links between toxocariasis and achievement gaps noted among socioeconomically disadvantaged groups?
Finally, the Gulf Coast is at great risk for viruses transmitted by mosquitoes. Dengue fever emerged in Houston in 2003, and then later in Florida. West Nile virus infection is becoming an important cause of neurologic and renal disease; Chikungunya will likely follow. In many instances it's the homeless and those living in poor-quality housing — with broken window screens or none at all — who are most exposed to mosquitoes and become infected with these viruses.
My hope is that the current Ebola crisis in West Africa will heighten awareness of other neglected tropical diseases affecting our most vulnerable populations — especially Americans who live in extreme poverty. We need a coordinated plan to conduct studies in vulnerable communities in the US in order to determine more precisely how many people are affected. We also need to better understand how the poor are becoming infected, and what it is about poverty that makes them susceptible. We need to make diagnostic tests more available, and begin educating physicians and other health care providers about how to recognize, manage, and treat these infections. Finally, we need programs of control, prevention, and research and development for new and improved drugs and vaccines.
This year, the End Neglected Tropical Diseases Act (HR 4847) was introduced in the US Congress. The bill represents an important first step toward tackling neglected tropical diseases abroad and at home. But we need even more help.
Peter Hotez, MD, PhD is Dean of the National School of Tropical Medicine and Texas Children's Hospital Endowed Chair in Tropical Pediatrics at Baylor College of Medicine in Houston. He is also President of the Sabin Vaccine Institute and a Baker Fellow in Disease and Poverty at Rice University.