Human Intestinal Parasites Correspondence and reprint requests should be addressed to:

Parasitic infections, caused by intestinal helminths and protozoan parasites, are among the most preva-lent infections in humans in developing coun-tries. In developed countries, protozoan parasites more commonly cause gastrointestinal infections compared to helminths. Intestinal parasites cause a significant morbidity and mortality in endemic countries. Helminths are worms with many cells. Nematodes (roundworms), cestodes (tapeworms), and trema-todes (flatworms) are among the most common helminths that inhabit the human gut. Usually, helminths cannot multiply in the human body. Protozoan parasites that have only one cell can multiply inside the human body. There are four spe