The Worldwide Threat of Intestinal Parasites

Some maladies are so commonplace throughout the developing world that when acutely malnourished children arrive at Action Against Hunger’s Therapeutic Feeding Centers, they are routinely dosed with three medications:

• Amoxicillin, an antibiotic effective against a wide spectrum of infections;
• An anti-malarial drug (the particular medication depends on the local strain of malaria and the specific treatments officially approved by the country’s health ministry);
• Medendazole, which kills most intestinal worms.

Intestinal parasites, in fact, are among the most common human diseases indeveloping countries (though no one has produced authoritative statistics to document their precise prevalence). These parasites typically cause diarrhea, which is a leading cause of death among children in developing nations.

Lethal diarrhea isn’t the sort of fleeting stomach upset cured by Pepto-Bismol. Persistent diarrhea caused by intestinal parasites leads to dehydration, malnutrition, weight loss, stomach pain, loss of blood in bodily excretions and death. Children in developing nations who fail to gain weight and lack energy are nearly always infested with intestinal parasites. These infestations cause diarrhea and intestinal deterioration, and meanwhile the parasites are stealing nutrition for themselves from the children’s food. In this way, intestinal parasites lead to dangerous malnutrition even when infected children have access to adequate diets.

Everyone Has Intestinal Parasites

Researchers have estimated that each of us carries 100 trillion bacteria in our intestines and perhaps as many as 100 different varieties of parasites—many of which aid in transforming our food into digestible nourishment, making certain species beneficial, even essential.

But most intestinal parasites are dangerous. Healthy individuals have some natural resistance—gastric acids, the swift passage of food through the intestines, and perhaps antibodies, though evidence of the efficacy of antibodies against intestinal parasites is inconclusive. But malnourishment compromises any natural resistance.

How Victims Get Sick

Unlike many viruses such as the one that causes AIDS, intestinal parasites can survive outside the body in the environment, especially in warm, moist climates. Parasites are usually found in communities with poor sanitation where they are deposited into the environment in human feces. Some communities in developing countries use human waste as fertilizer for food crops. Wastes can also get into the water supply, where they contaminate water used for drinking and irrigating crops. Dirty hands also spread parasite infestation. Though breast-fed infants are seldom infected, once children start to crawl or eat solid food, they’re at risk.

By definition, all infectious agents are parasites. Intestinal parasites, however, are usually helminths or protozoans.

Helminths are worms that look more or less like earthworms. The varieties found most commonly in human intestines are roundworms, whipworms or hookworms, and each can coexist with the others in the intestines. In developing countries, roundworms are the most common, estimated to infect more than 25% of the population. And they’re prolific: A single female roundworm can produce 200,000 eggs a day.

Roundworms and whipworms are typically ingested via contaminated food, usually fruits and vegetables that have been irrigated with contaminated water. Whipworms can grow to 1.5 inches in length, roundworms to 14 inches.

Hookworms burrow through the skin, usually through the soles of the feet, often leaving behind an itchy rash known as ground itch. Hookworms enter the bloodstream and travel to the lungs where they are coughed up and swallowed. They settle in the small intestine where they grow to two-fifths of an inch.

All helminths reduce appetite, steal nourishment and prevent proper absorption of nutrients.

Protozoans are single-celled organisms so small they can be seen only with a microscope. There are many more varieties of protozoans than of helminths, including cyrptosporidia, cyclospora, giardia, and trichuriasis. Unlike helminths, which reproduce outside the body, protozoans breed in the intestines. Then they pass outside the body carried by feces in forms known as cysts, which are covered with a protective layer that resists most common disinfectants such as chlorine. Cysts are re-ingested when a host consumes contaminated food or water, and each cyst typically divides into eight new protozoans.

Medical writers have called intestinal protozoans “microscopic vampires.” Theydestroy intestinal cells that absorb nutrients, and as the host’s natural resistance is weakened due to malnutrition, protozoans multiply, further debilitating the host.

Treatment

In Action Against Hunger’s nutritional rescue protocol, patients with chronic diarrhea are immediately dosed with ReSoMal, an oral re-hydration salt that helps the body retain water. Of the three routine medications for all patients, the medendazole usually kills any helminths, and the amoxicillin kills most protozoans. If diarrhea persists, the patient’s excrement is examined to identify the resistant protozoan, and additional drugs are prescribed specifically to eliminate it.

Still, any patient sent back into an environment that produced the infection will inevitably become re-infected. The only certain long-term cure for intestinal parasites requires educating a community’s populace about the necessity of keeping clean and improving local sewage systems—and also convincing everyone that to remain healthy they must maintain a sanitary environment.

ACF missions conduct education programs whenever inadequate sanitation is allowing parasites to thrive. Mission staffs teach committees of villagers how to maintain their sources of clean water, to wash their hands before handling food or water, to boil water from uncertain sources, and to keep containers of food and water clean. These committees in turn educate their neighbors. Similarly, the staffs at feeding centers teach the same lessons to beneficiaries. In taking action against parasites, the job of enlightening populations at risk is as urgent as medicating them.