Final answer:
To prevent parasitic infection in dogs and cats, it's essential to control both the egg and larva stages of the parasite's life cycle. Hookworm and roundworm eggs can contaminate the environment and the larvae can further infect the host.
Step-by-step explanation:
To prevent parasites from infecting our dogs and cats, we must be aware of two critical stages in their life cycle: the egg and larva stages. Parasites, including roundworms and hookworms, produce a large number of eggs that are passed out in the host's feces and contaminate the environment. Other animals or humans may become infected by ingesting these eggs from contaminated soil, food, or water. The ingested eggs then hatch into larvae within the new host, which can cause significant health issues.
Larvae of certain parasites can penetrate the skin or be swallowed when an animal comes into contact with contaminated soil or feces. These larvae then mature into adult parasites inside the host. Additionally, some parasites like hookworms and Strongyloides stercoralis can cause a condition called cutaneous larva migrans, where the larvae migrate under the skin causing itching and visible tracks. Thus, controlling the spread of eggs and preventing the infestation of larvae are key to stopping the cycle of parasitic infections.