Wednesday, March 3, 2010

Horrors of the Kissing Bug

The U.S., too, suffers high rates of parasitic diseases. These so-called neglected infections of poverty closely resemble the neglected tropical diseases (NTDs) and are found pre-dominantly in areas of intense poverty. They disproportionately affect African-Americans and Hispanic-Americans, because a higher percentage of these populations live in poverty and under stressful conditions.

In the Mississippi Delta, post-Katrina Louisiana and other areas of the American South, as well as in inner cities, an estimated three million African-Americans are either currently infected or have been infected in the past with a helminth infection known as toxocariasis. The worm eggs are found in soil or sand laced with dog feces and can contaminate food. Once the worm eggs hatch in the digestive tract, the released larvae migrate through the lungs, liver and brain, leading to wheezing, seizures and developmental delays. Another infection is trichomoniasis, a sexually transmitted protozoan parasite that causes inflam-mation and hemorrhages in the cervix. It increases the risk of acquiring additional sexually transmitted diseases, possibly including HIV/AIDS.

Among Hispanic-Americans, two important infections of poverty are Chagas disease and cysticercosis. Chagas results from a trypanosome protozoan acquired when people are bitten by a kissing bug, a type of assassin bug—a cockroachlike insect often found in dilapidated housing where rats nest (photograph above). The parasites can produce a severe dilation of the heart and can prove fatal. An estimated 300,000 people in the U.S. have Chagas disease. Cysticercosis is a parasitic helminth infection that occurs in as many as 170,000 people and is the leading cause of seizures in cities near the Mexican border.

Most of these infections were not introduced into the U.S. as a result of immigration. Instead they most likely persist through transmission within U.S. borders. Despite their prevalence, research on these conditions has been fairly limited. Health officials do not know the precise numbers of people infected or why poverty is a risk factor. Diagnostic methods and treatments are also fairly rudimentary.

chagas disease afflicts an estimated 300,000 people in the U.S. Screening of donated blood, started in 2007, finds that cases are concentrated in areas with large numbers of immigrants from Latin America living in substandard housing.

Source of Information : Scientific American January 2010

No comments: