PRESIDENT OBAMA has started an ambitious global health initiative that will deliver urgently needed medicine and preventative care to hundreds of millions of people in poor countries. Included in the plan are efforts to devote resources to “neglected tropical diseases,” afflictions like hookworm infections, river blindness and elephantiasis that many think have gone the way of smallpox, but which still make up the most common ailments among the world’s bottom billion.

Just off the beautiful beaches of the Caribbean islands popular with American vacationers live millions who suffer from neglected tropical diseases. In Haiti and the Dominican Republic, more than 600,000 people are infected with lymphatic filariasis, a parasitic infection also known as elephantiasis for the profound disfigurement it produces in the limbs and genitals. In the Dominican Republic, 250,000 people are infected with the blood flukes that cause schistosomiasis, and more than a million in the region have hookworms. Intestinal worms are also common in Jamaica, Barbados and Grenada, where they cause chronic anemia, as well as stunted growth and impaired intellectual development in children.

Distressingly, some of these diseases have been found in the United States. Researchers have uncovered similar neglected infections like toxocariasis and trichomoniasis, two parasitic infections, among African-Americans living in poverty, particularly in the South and disadvantaged urban areas. In Baltimore and Detroit, there have been appearances of a bacterial infection known as leptospirosis. Nearly three million African-Americans have toxocariasis, a parasitic worm infection transmitted by dogs that can cause asthma and developmental delays. And thousands of African-American infants are born annually with congenital cytomegalovirus, which can result in hearing loss and severe mental disability.

Of course, African-Americans are not the only ones who suffer from these diseases. Hundreds of thousands of Hispanic Americans are infected with Chagas disease, a parasitic infection that causes heart disease. Cysticercosis, a parasitic brain infection, is a leading cause of epilepsy among this same population. And whites living in poverty are also at risk.