Parasites
What is a parasite?
• Parasitism is a type of symbiotic relationship
between two different organisms. The parasite
benefits from a prolonged, close association with
the host, which is harmed
• Many possess special adaptations
Tapeworms
Tapeworms
• Up to 35 feet long
• Lay millions of eggs each day
• Attach to the intestines and absorb nutrients
from its host
Hookworms
Hookworms
• Burning lake water?
• Hookworms enter through the skin and migrate
through the bloodstream to the lungs and
intestines. They may also be ingested through
contaminated food or water. You may have
itchiness or redness where the larvae penetrate
the skin (most likely your feet).
• One symptom is craving to eat soil
Roundworms
Roundworms
• Here is a staggering statistic: the World Heath
Organization reported that about 25% of the
world’s population is infected with roundworm.
• These parasites can grow to 13 inches inside the
intestine and can lay as many as 300,000 eggs in
a single day
• Ascaris lumbricoides
• Partial cause of distented stomachs in starving
children
Pinworms
Pinworms
• Have you ever been awakened in the middle of
the night by an itchy anus? If so you have these
little guys. They sneak out at night to lay their
eggs on the fertile skin surrounding your anus!
• Get these nasty little guys from contaminated
food
Special parasites
• While all parasites possess special adaptations to
be able to survive in their host, some are more
bizarre than others…..
Human Bot Fly
Human bot fly
• http://www.youtube.com/watch?emb=0&aq=f&
aq=1&v=4B7Top18qXY&eurl=http%3A%2F%2Fvide
o.google.com%2Fvideosearch%3Fq%3Dbot+fly&
oq
• Lays egg in human host. Larvae grows and
eventually falls out
Candiru
Candiru
• Type of catfish with tiny barbs
• Usually parasitizes fish gills
• Has been known to follow urea trails and swim
up the urethra
Castrating Barnacles
Castrating barnacles
• Briarosaccus callosus
• Find way into crab through a ‘kink’ in
exoskeleton
• Eventually can control crab
Leucochloridium paradoxum
Leucochloridium paradoxum
• Leucochloridium paradoxum are a type of fluke
(a.k.a., parasitic flatworm) that prey on
• They take up residence in the snail’s eyestalks.
As they mature, the flukes become visible
through the snail’s translucent skin and look like
caterpillars.
• Birds eat these, and the cycle starts again
Cymothoa exigua
Cymothoa exigua
• A parasitic crustacean
• Attaches itself to a fishes tongue and feeds on
the blood
• Eventually the tongue atrophies, and this
parasites functionally replaces the old tongue
with its own body.
Lamprey’s
Lamprey
• Type of parasitic fish
• Attaches to passing fish and feeds on their blood
• Very specialized mouth parts
Filaria Worm
Filaria worm, Wuchereria bancrofti
• Elephantitis is a disease caused by the parasite
Wuchereria bancrofti. This parasite is introduced
into the body by a mosquito bite. The parasite will
then migrate to the lymphatic system. The parasite
does not cause any direct harm to the host; it is the
side effects of the infestation that cause the damage.
• Elephantiasis is the result of the parasites blocking
the lymphatic ducts. With the lymphatic ducts
blocked, the lymph fluid does not circulate well and
will accumulate, causing swelling.
Filaria worm, Wuchereria bancrofti
• filarial worm embryos living underneath the skin
can sense the onset of night, which is their cue to
head upward to the skin’s surface in order to
increase their chances of being picked up by a
passing mosquito
• But not all organism negatively affect their host:
Coolest Symbiosis Example
Boxer Crab, Lybia tessellata