Pork tapeworm - a gut endoparasite

• what must animals avoid?

  they must avoid competition with other animals and must avoid becoming prey
• does the gut parasite Taenia solium, the pork tapeworm, have any competition

  no
• can the gut parasite Taenia solium, the pork tapeworm, be prey?

  no as its an endoparasite
• what are the features of a pork tapeworm?

  • its ribbon-like, hence its name
  • its shape allows plenty of space for the host’s food to move past it
  • its up to 10 metres long
  • its anterior end is the scolex, made of muscle carrying suckers and hooks
  • its body is a linear series of sections called proglottids
• what does the shape of the pork tapeworm allow?

  it allows plenty of space for the host’s food to move past it
• how long can a pork tapeworm become?

  up to 10 metres long
• what is the anterior end of a pork tapeworm called?

  the scolex
• what is the scolex of a pork tapeworm made of?

  its made of muscle carrying suckers and hooks
• what are the linear sections of a pork tapeworm called?

  proglottids
• what does the pork tapeworm’s life cycle require it to do?

  it requires the tapeworm to alternate between its 2 hosts: the primary host in the human and the secondary host in the pig
• what are the 2 hosts that the pork tapeworm has to alternate between?

  • primary host - human
  • secondary host - pig, in which the larval forms develop
• how do pigs become infected with the pork tapeworm?

  they become infected when their food is contaminated with human faeces
• how do humans become infected with pork tapeworms?

  by eating undercooked pork containing live larval forms
• where does the pork tapeworm live?

  in an immediate source of food
• what does the pork tapeworm have to survive in hostile conditions in the gut?

  • its surrounded by digestive juices and mucus
  • it must withstand peristalsis
  • it experiences pH changes as it moves down the gut to the duodenum
  • if the host dies, the parasite dies too
• what is this an image of?

  a pork tapeworm

  
• what are the structural modifications the pork tapeworm has to allow it to live as a gut parasite?

  • a scolex with suckers and hooks
  • a thick boy covering, the cuticle
  • makes enzyme inhibitors
  • a very reduced gut
  • its a hermaphrodite
  • the eggs have resistant shells and survive until eaten by a pig
• how does the scolex having suckers and curved hooked help the pork tapeworm to live as a gut parasite?

  a scolex with suckers and a double row of curved hooks attach it strongly to the duodenum wall
• how does a thick body covering help the pork tapeworm to live as a gut parasite?

  a thick body covering, the cuticle, protects it from the host’s enzymes and immune system
• how does making enzyme inhibitors help the pork tapeworms live as a gut parasite?

  by making enzyme inhibitors (anti-enzymes), prevent the host’s enzymes digesting it
• how does having a very reduced gut help the pork tapeworms live as a gut parasite?

  as it has a very reduced gut, it has a large surface area to volume ratio which lets it absorb pre-digested food over its whole surface
• how does the pork tapeworm being a hermaphrodite help it to live as a gut parasite?

  • each proglottid has male and female reproductive organs
  • an infected gut usually has only 1 tapeworm, but each mature proglottid may contain 40,000 eggs, which pass out of the host’s body with the faeces
  • this huge number of eggs increases the chance of infecting a secondary host
• how does the eggs having resistant shells help pork tapeworms live as a gut parasite?

  • the eggs have resistant shells and survive until eaten by a pig
  • then the embryos hatch and move through the intestine wall into the pig’s muscles
  • they remain dormant there until the meat is eaten by a human