Roundworms

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Roundworms

• Belong to Phylum Nematoda

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Roundworms are EVERYWHERE!!

• Roundworms are all around us.
• They vary in size from microscopic to a few
  meters long
• A single rotting apple can have as many as 90,000
  roundworms and a small bucket of soil or pond
  water can have as many as 1 million

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Main Characteristics of Roundworms

• Unsegmented- meaning they have no distinguished
  body parts
• Bilaterally symmetrical
• Simplest animal to have a digestive system with
  two openings both an anus and a mouth

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• have a pseudocoelom meaning that they have a
  colon that is not completely covered by mesoderm.

mesoderm
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• Have several ganglia-groups of nerves-but lack a
  brain
• Have a pharyngeal nerve ring
• Muscles run in strips along the length of the
  body walls
• Breath and excrete their metabolic wastes through
  their body walls

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• Body is covered with a cuticle
• Has no circulatory system
• Body has more than two cell layers, tissues, and
  organs
• Ecological roles free-living parasitic

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Roundworm Reproduction

• Roundworms reproduce sexually
• Most species have separate male and female,
  though some are hermaphrodites
• Fertilization takes place inside the female
• She later then lays eggs, which turn to larvae,
  then to adult worms

Roundworm Egg
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Affects on Human Life

• Though they are very numerous around the world,
  roundworms do not exert a lot of positive
  influence in the everyday lives of humans so they
  are easy to ignore
• parasitic roundworms are responsible for some
  terrible diseases

Heartworm
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Parasitic Roundworms
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• Ascaris is a parasitic roundworm that affects
  humans (700 million people globally), horses,
  cattle, pigs, dogs, cats, and other animals
• Puppies are dewormed to get rid of the ascarids,
  as they are called

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Ascaris Life Cycle

• 1.Adult worms live in the intestines. Eggs are
  passed with the feces
• 2.Infective eggs are swallowed by other host via
  contaminated food or water
• 3.The larvae hatch in intestines of new host
• Young worms burrow into the intestinal wall, and
  are carried through circulation to the lungs.
• 5. The larvae mature further in the lungs (10 to
  14 days), penetrate the alveolar walls, ascend to
  the throat, and are swallowed.
• 6. reaching the small intestine, they develop
  into adult worms

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HOOKWORMS
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Hookwormsworm

• Found in southern U.S. tropics
• 600 million people are infected with hookworms
• adult hookworm lives in the small intestine of
  its host where it hangs on to the intestinal wall
  using its sharp teeth
• hookworm feeds by drinking its hosts blood

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• adult worm lives and mates within the hosts
  intestine and ultimately, the female worm
  produces eggs
• eggs are released into the intestinal contents
  and passed out with feces
• egg hatches to a larva which can infect its new
  host in several ways by 1) penetrating the
  hosts skin directly through the feet or belly or
  2) larva ingested by host as it cleans or licks
  itself

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• Once larvae are inside the host, they either
• 1) go to intestine to mature into adulthood or
• migrate to the lung tissue where they develop
  further
• From the lung, they climb up the trachea, get
  coughed into the throat and swallowed.
• Once back in the intestine, they complete their
  maturation to adulthood and reproduce

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Trichinosis
Cyst

• Caused by a Trichinella species of roundworms
• The adult worms live and mate in the intestines
• Females carring fertilized eggs burrow into the
  intestinal wall and release up to 1500 larvae
• The larvae then travel through the blood stream
  until they find a tissue to burrow into

Worm

• This burrowing causes Great Pain towards its
  host
• The larvae form cysts inside the muscle tissue of
  the host and become inactive.

Larvae
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• complete their life cycle when the muscle tissue
  is eaten
• (only carnivores can be infected)
• Most common animals infected are rats and pigs
• People get this disease from eating not
  completely cooked rat or pork

PIGS
RATS
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Filarial Worms

• Found in tropics
• Thread-like worms
• Live in blood/lymph vessels of birds and mammals
• Transmitted by mosquitoes
• Can block the lymphatic vessels causing
  elephantiasis

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Elephantiasis
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http//www.boldsky.com/health/disorders-cure/2013/
loa-loa-eye-worm-033065.html
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Eye Worms

• Related to filarial worms
• Found in Africa
• Infect humans and baboons
• Live in sub-cutaneous tissues
• Sometimes travel across the eye

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