Washington, May 24 (IANS) Mummies are revealing how age-old irrigation techniques may have boosted the plague of schistosomiasis, a water-borne parasitic disease that infects an estimated 200 million people today.

An analysis of mummies from Nubia, an ancient kingdom located in present-day Sudan, provides the first ever details about the prevalence of the disease across populations, and how human alteration of the ecology may have spurred its spread.

About 25 percent of mummies, dating back to about 1,500 years ago, were found to have schistosoma mansoni, a species of schistosomiasis linked with more modern-day irrigation
techniques, reports the American Journal of Physical Anthropology.

Schistosomiasis can cause anaemia and chronic illness that impairs growth and cognitive development, damages organs, and increases the risk for other diseases. Along with malaria, it ranks among the most socio-economically damaging parasitic diseases in the world.

"Often in the case of prehistoric populations, we tend to assume that they were at the mercy of the environment, and that their circumstances were a given," said study co-author Amber Campbell Hibbs, doctoral graduate in anthropology from Emory University.

"Our study suggests that, just like people today, these ancient individuals were capable of altering the environment in ways that impacted their health," Hibbs said, according to an Emory statement.

The study was co-authored by George Armelagos, Emory anthropologist, William Secor, epidemiologist at the Centres for Disease Control and Prevention, and Dennis Van Gerven, anthropologist at the University of Colorado at Boulder.

"We hope that understanding the impact of schistosomiasis in the past may help in finding ways to control what is one of the most prevalent parasitic diseases in the world today," Hibbs said.

Schistosomiasis is caused by parasitic worms that live in certain types of freshwater snails. The parasite can emerge from the snails to contaminate fresh water, and then infect humans whose skin comes in contact with the water.

As far back as the 1920s, evidence of schistosomiasis was detected in mummies from the Nile river region, but only in recent years did the analysis of the antigens and antibodies of some of the individuals become possible.