Necator americanus is a species of hookworm (a type of helminth) commonly known as the New World hookworm. Like other hookworms, it is a member of the phylum Nematoda. It is an obligatory parasitic nematode that lives in the small intestine of human hosts. Necatoriasis—a type of helminthiasis—is the term for the condition of being host to an infestation of a species of Necator. Since N. americanus and Ancylostoma duodenale (also known as Old World hookworm) are the two species of hookworms that most commonly infest humans, they are usually dealt with under the collective heading of "hookworm infection". They differ most obviously in geographical distribution, structure of mouthparts, and relative size. Necator americanus has been proposed as an alternative to Trichuris suis in helminthic therapy. Morphology This parasite has two dorsal and two ventral cutting plates around the anterior margin of the buccal capsule. It also has a pair of subdorsal and a pair of subventral teeth located close to the rear. Males are usually 7–9 mm long, whereas females are about 9–11 mm long. The typical lifespan of these parasites is 3–5 years. They can produce between 5,000 and 10,000 eggs per day. Habitat N. americanus is primarily found in tropical and temperate areas. This parasite thrives in warmer climates because to hatch, the eggs require a moist, warm, and shaded environment. The thin, smooth shells of this species cause the eggs and juveniles to die in freezing temperatures or with soil desiccation. Therefore, the type of soil where the parasite resides is also very important for their ideal living conditions. Ideal soil conditions tend to be in areas where water is able to drain at a standard pace, and the size of the soil particles is neither too large nor too small. That way, the degree of dampness, as well as the openings in the soil, allow the parasites to burrow to the surface and attach to the skin of their next host. High transmission rates seem to be congruent with the heavy rains and warm temperatures that are characteristic of tropical climates. One anomaly of this species is that it appears to prefer male hosts to female hosts, likely because of the division of labor in regions of its prevalence. Lifecycle This worm starts out as an unembryonated egg in the soil. After 24–48 hours under favorable conditions, the eggs become embryonated and hatch. This first