More than 450 million people worldwide, primarily children and pregnant women, suffer illness from soil-transmitted helminths, intestinal parasites that lives in humans and other animals. Administration of drugs is the most common prescription for infection control. But a more effective treatment could be to invest in sanitation-based approaches to eliminate the parasites, as well as to provide additional benefits to society.
Fecal-polluted soil spreads soil-transmitted helminths, a group of parasitic nematodes of humans that includes roundworms, hookworms, whipworms, and threadworms. They are commonly found throughout the tropics and subtropics, accompanied by poverty and poor sanitation. Many rural areas lack any form of sanitation facilities, and human waste is used as fertilizer by farmers, further spreading the parasites.
The World Health Organization has been attacking this problem through mass drug administration, using existing public health care infrastructure to reach people. Immunizations are given once or twice yearly, and donations from pharmaceutical companies have helped defray costs. However, issues of reinfection, drug resistance, and continued sustainability work against this program.
An article in The Journal of Parasitology suggests that long-term efforts to control parasitic infections should focus on improving sanitation within a culturally acceptable framework. Safe disposal of human waste has been shown to reduce soil-transmitted helminth prevalence and reinfection rates. Western-style sanitation systems are not feasible in many regions, but individual sanitation systems, such as the “biodigester,” being used in areas of rural China, offer a solution.
The biodigester is an individual household anaerobic fermentation system used to process organic waste. Waste enters underground chambers from the toilet and pigpen. Methanogenic bacteria then acts on the organic material, resulting in methane and other gases, referred to as ‘biogas.” The gas is colorless, odorless, burns similarly to liquid propane, and can provide almost 60 percent of a family’s energy needs. The biodigester can also produce nitrogen-rich fertilizer that does not contain infective parasite eggs.
Cost is often an obstacle to improving sanitation in underdeveloped parts of the world. However, the biodigester offers grassroots, community-driven sanitation without the cost of Western-style sanitation infrastructure. Its long-term costs could be much lower than the current disease treatment approach, making it a cost-effective public health intervention.
Full text: “Controlling Soil Transmitted Helminths: Time to Think Inside the Box?” The Journal ofParasitology, Vol. 100, No. 2, 2014.
Source: News Release from the Journal of Parasitology