CAUTION! Intestinal parasites of dogs and cats are potential health hazards for humans, too. If hookworm larvae penetrate the skin they can cause "cutaneous larval migrans", a potentially serious and scarring inflammation results. Ascarid (roundworm) eggs if ingested can cause a disease called "visceral larval migrans" where tiny worm larvae migrate through the person's intestinal wall and into the body tissues. They then grow to larger size almost anywhere in the body. Ocular disease is a common sequel "visceral larval migrans". Children are at most serious risk especially if play behavior is in an environment where dog, cat, or raccoon feces may be present... such as in a sandbox. A single adult Toxicara canis female can shed up to 100,000 eggs a day which pass into the dog or cat's environment with the stool. Please take the worming advice of your veterinarian seriously and adhere to strict sanitation principles whenever pets and children are in close contact. Note... roundworms are not spread to people simply by close contact with dogs or cats. The individual must ingest (eat!) the infective stage of the roundworm eggs; since the eggs are primarily associated with feces, humans would somehow need to consume the egg contaminated feces for contagion to occur. To learn more about parasites of man and animals look at the Centers For Disease Control site at cdc.gov. If you search for "Prevention of Zoonotic Transmission of Ascarids and Hookworms of Dogs and Cats" you can see information about roundworm and hookworm hazards for humans.<SNIP>

Let's examine each type of worm individually:

<SNIP> Read Full article and see many photos here: http://www.thepetcenter.com/exa/worms.html