Hookworm parasite.

Hookworm is a disease that once plagued much of the United States, especially in rural areas of the South. Through modern sanitation and hygiene improvements, much of the infection was beaten back through the course of the 20th century.

But a rural nook of central Alabama continues to battle the parasite in the 21st century – largely because of a raw sewage problem in the impoverished community there, according to a new report in The American Journal of Tropical Medicine and Hygiene.

While just a tiny fraction of the 430 million hookworm cases worldwide is found in the United States, as much as a third of the people of Lowndes County (pop. 13,000) continue to be infected with the stubborn parasite.

Scientists from Baylor College of Medicine and a group called the Alabama Center for Rural Enterprise traveled Lowndes County looking for the prevalence of Necator americanus, the soil-transmitted helminth endemic to the American South.

The scientists found 24 households who responded to a survey – and 55 people who agreed to give stool samples to help the investigators. Tests for the parasites focused on the critters’ DNA, using a multiparallel quantitative real-time PCR.

Approximately 42 percent of the households reported raw sewage seeping into their homes. Nineteen of the stool samples (approximately 34.5 percent) showed hookworm infections. (An additional four showed threadworm infections, and another single case showed the presence of Entamoeba histolytica).

The hookworm and other parasites are spread through fecal contamination of soil, and especially through the penetration of the skin of the bare feet.

The parasite problem in Lowndes County is linked to the problems of sewage and poverty, the researchers write. The geologic location is sometimes described as the “Black Belt” because of a sedimentary limestone bed covered over with layers of dark and rich dirt. Proper sanitation would require digging and installing a septic waste system – but the per-capita income is just over $18,000. So instead, the rural residents use something called “straight piping” – which involves rigging a series of ditches and pipes to guide human waste away from homes. Most of such diversions never extend past 10 meters – and in periods of heavy rains or floods, the feces travels back into the homes, the residents told the paper’s authors. 

This region of the South has historically shown a parasite problem. Widespread surveys in the 1930s showed a majority of people (53.6 percent) were infected with hookworm. Smaller surveys in southern Alabama showed a rate of about 40 percent.

About three-quarters of the 13,000 people who live in Lowndes County are identified as black. Thirty-one percent live in poverty. The area has a history of racial violence that resulted in the nickname “Bloody Lowndes” that extended into the Civil Rights era of the 1960s and 1970s

Hope for reducing hookworm infections in Lowndes and beyond could be coming soon from new scientific breakthroughs. Clinical testing on the first hookworm inoculation for humans is currently underway, as a team of scientists reported in the Elsevier journal Vaccine last year.