Nematodes (Helminths)
Nematodes (Helminths): Lifecycle in Humans, Diagnosis, and Treatment Definition Nematodes (Roundworms) Phylum: Nematoda Characteristics: Cylindrical, elongated, unsegmented bodies Habitats: Soil, Water, Parasitic environments (plants and animals, including humans) Lifecycle in Humans 1. Ingestion/Penetration: Ingest eggs/larvae via food, water, soil; some penetrate skin. 2. Larval Migration: Larvae move through tissues (e.g., lungs, intestines). 3. Adult Stage: Mature in specific body locations (e.g., intestines, lymphatics). 4. Reproduction : Adults reproduce; eggs excreted in feces or remain in tissues. 5. Environmental Stage : Eggs/larvae develop in environment; become infectious. Ascaris lumbricoides Example 1. Ingestion: Ingest eggs via contaminated food/water. 2. Hatching: Eggs hatch in intestines. 3. Migration: Larvae move to lungs, then throat, swallowed back to intestines. ...