Final answer:
The mechanism of entry for Naegleria Fowleri is inhalation. Infected individuals usually contract it while swimming in warm bodies of freshwater. The pathogenic trophozoite enters through the nasal passages and reaches the brain, causing severe symptoms and potentially leading to death.
Step-by-step explanation:
The mechanism of entry for Naegleria Fowleri is inhalation. This ameboflagellate is commonly found free-living in soils and water. Individuals are typically infected by the amoeba while swimming in warm bodies of freshwater such as rivers, lakes, and hot springs. The pathogenic trophozoite infects the brain by initially entering through nasal passages to the sinuses and then moving down olfactory nerve fibers to penetrate the submucosal nervous plexus, invades the cribriform plate, and reaches the subarachnoid space.