Here is some info on worms:
Hookworms:
Hookworms are found throughout North America, although A. braziliense is more
common in semitropical and tropical areas, and U. stenocephala in the colder north.
Their life cycle has an unusual twist – animals can be infected by ingestion of larvae
either from contaminated soil or water; by eating an infected transport host; through
larvae penetrating their skin, and by larvae infecting fetuses or the young via the
uterus or mammary glands.

Whipworms:
A dog or cat becomes infected by ingesting food or water contaminated with
whipworm eggs. The eggs are swallowed, hatch, and in three months, the larvae
mature into adults in the cecum and large intestine where they burrow their mouths
into the intestinal wall and feed on blood. Adult worms lay eggs that are passed in
the feces. The eggs must remain in the soil for about a month to mature and be
capable of causing infection.

More info:
Worm info at Pet Education