Download Roundworm

Roundworms
Phylum Nematoda
1. Nematode: “round”
2. Live in most envir.
3. Free-living or parasitic
4. Smaller than
flatworms, taper at
both ends
5. Thick outer covering to
protect them from
stomach acid
1. Move bodies with
thrashing motion
2. Bodies have two
openings:
mouth and anus
3. Pseudocoelomates
4. Sexually
reproduce:
a. Male & Female
b. some
hermaphrodites
Life Cycles of
Parasitic Roundworms
A. ASCARIS
1. Lives in intestines & feeds
off blood
2. Ingest eggs from dirty hands
or unwashed
veggies contaminated
w/fecal matter
3. Eggs hatch in int. & enter
bloodstream
4. Larval worms bore
into lungs
5. Must be coughed up and
swallowed
6. Move to intestines
where they mature
B.TRICHINELLA
1.
2.
3.
4.
Bore into muscles
Cause painful cysts
Live in intestines
Ingest cysts in
undercooked raw meat
(usually pork)
5. Cysts open up in
intestines & reprod.
6. Larvae move into
muscle tissue & form
cysts
C. HOOKWORMS •
•
•
•
•
•
•
•
Lives in intestines
Feeds on blood
Causes major damage
to intestines
Eggs deposited on soil
from contaminated
wastes
Larvae live in soil
Burrow into feet or
exposed skin of host
Larvae travel through
bloodstream, to lungs,
coughed up, swallowed
Attach to intestinal
wall where they mature
C. PINWORMS
• Most commonly
infects children
• Lives in intestines
• Ingest eggs from
contaminated soil
or sand
• Hatch in intestines
• Female lays eggs
near anus at night
causing severe
itching
D. Filarial Worm
 Filiariasis is the name for a
group of tropical diseases
caused by various thread-like
parasitic round worms
(nematodes) and their larvae.
 The larvae transmit the disease
to humans through a mosquito
bite.
 Filariasis is characterized by
fever, chills, headache, and skin
lesions in the early stages
 If untreated, can progress to
include gross enlargement of
the limbs and genitalia in a
condition called elephantiasis.
Quiz: Roundworms
1. Nematodes are ___ worms.
a. flat b. round c. segmented
2. Roundworms have two body openings: ___.
a. mouth, pharynx b. osculum, anus c. mouth, anus
3. Ascaris worm infections come from ___.
a. dirty hands or infected vegetables
b. infected fish or other meats
c. pond water
4. Hookworm infections come from ___.
a. dirty hands or infected vegetables
b. infected fish or other meats
c. walking barefoot on infected soil
5. Female ___ lay their eggs near the anus at night
causing severe itching.
a. ascaris worm b. pinworms
c. trichina worms