ASCP Parasitology Practice Exam 2025 – Comprehensive Study Resource

Ascaris lumbricoides is indeed known as the common roundworm. This nematode is one of the largest and most common parasitic worms found in humans. It typically infects the intestines and can cause gastrointestinal problems. The organism is particularly prevalent in areas with poor sanitation and inadequate hygiene practices, as its eggs can be transmitted through contaminated food and water.

The lifecycle of Ascaris lumbricoides involves the ingestion of eggs, which then hatch in the intestines, allowing the larvae to migrate through the bloodstream to the lungs and back to the intestines, where they mature into adult worms. This distinctive lifecycle contributes to its classification as a roundworm due to the cylindrical shape of its body.

The other organisms mentioned, such as Trichuris trichiura, Fasciola hepatica, and Clonorchis sinensis, represent different types of parasitic infections with distinct characteristics and lifecycles that do not align with the definition of roundworms. Trichuris trichiura is known as whipworm, Fasciola hepatica is the liver fluke, and Clonorchis sinensis is known as the Chinese liver fluke. Each of these organisms affects the body in different ways and belongs to