Despite plummeting mortality rates for most infectious diseases over the last century, a group of largely overlooked bacterial, viral and parasitic infections is still plaguing the nation’s poor, according to a report released this week.
Many of the diseases are typically associated with tropical developing countries but are surprisingly common in poor regions of the United States, according to the analysis, published in the Public Library of Science journal PLoS Neglected Tropical Diseases.
On its list of 24 “neglected infections of poverty” are schistosomiasis, a parasitic infection common in Africa; brucellosis, a bacterial infection from unsanitary dairy products; and dengue fever, a viral infection common in tropical Asia and South America.
Many of the diseases have become significant public health problems in the United States. In the Los Angeles area, a pork tapeworm infection called cysticercosis which spreads in crowded, unsanitary conditions, accounts for 10% of seizures resulting in emergency room visits, according to the report. Worm cysts in the brain cause the seizures and can lead to permanent epilepsy.
The 24 diseases afflict at least 300,000 Americans, and possibly millions, according to study author Dr. Peter Hotez, chairman of George Washington University’s department of microbiology, immunology and tropical disease.
“These are right now below everybody’s radar,” Hotez said.
Some of the diseases have been brought from overseas, the report says, but most have long existed in this country. The diseases are largely concentrated in poverty-stricken regions, including Appalachia, inner cities, the Mississippi Delta and the border with Mexico.
Often the result of poor sanitation or inadequate healthcare, they can hinder child development and worker productivity, exacerbating poverty, the study says.
Yet many of the diseases have received little attention, Hotez said. For example, nearly every hospital screens infants for the genetic disease phenylketonuria, but only two states require screening for toxoplasmosis, a parasitic infection passed from mother to child at birth. Both diseases cause mental retardation. Toxoplasmosis affects 10 times as many newborns as phenylketonuria does, but toxoplasmosis is mostly limited to inner cities and poor Southern areas.
The first step in combating the diseases is more closely monitoring their prevalence and transmission routes, Hotez said.
Though the conditions are often preventable or easily curable, many sufferers never receive medical attention.
“We do monitoring for all those diseases,” said Dr. Jonathan Fielding, Los Angeles County public health director. “Whether there’s 100% reporting is another issue.”
Dr. Lee Hall, chief of parasitology and international programs at the National Institute of Allergy and Infectious Diseases, said his agency funded research into the diseases, but primarily as global, not national, problems.
“Do we need better data? We probably do, but that’s probably true . . . for infectious diseases of the poor in general.”