In the poorest sections of the American South researchers are finding hookworm, dengue fever, and other parasites and viruses that are more commonly associated with developing countries or, in the United States, with the early years of the 20th century. . . . Failing septic systems and the use of straight pipes are not confined to Lowndes County, but the extent of the problem is largely unknown. According to Mark Elliot, a University of Alabama researcher, there have been only two rigorous, county-level studies in the United States to establish how many households have failing septic systems or straight pipe discharge. Both studies are more than a decade old.