Cestodes

Question 1

Cestodes

Answer 1

Live in the gut
R repro
Indirect
Eggs are accidently eaten by int hit
Larvae dev and form cysts
Once ingested the larvae complete their dev to adult in the gut of the final hist

Question 2

Structure of egg

Answer 2

Thick walled
Cont larvae with 6 hooks (oncosphere)
When ingested egg wall digested andlavae are released (hexacanth) larval stage
Burrow through the gut mucosa and enter the blood or lymph and migrate to predeliction site eg m and dev into metacestode

Question 3

Metacestode

Cystercirus

Answer 3

Fluid filled sac with one envaginated protoscolex

Question 4

Metacestode

Cornurus

Answer 4

Many protoscolexes

Question 5

Metacestode

Hydatid

Answer 5

Detached protoscolexed from cyst eall sonmany small cysts are formed in the main one

Question 6

Metacestode

Cystercercoid

Answer 6

Protoscolex cont within a solid cyst

Typically formed in tapeworms with invert hist

Question 7

Taenia multiceps

Answer 7

Coenurosis (gid)
W UK
Coenurus
Slowly progressive
Brain - cyst location determined by neuro clinical exam
Sheep dog

Question 8

Taenia hydatigena

Answer 8

Key cause of slaughterhouse rejection of sheep liver
Oncospheres in liver larval migration through the liver
Hexacanth move to omentum
Clin dis is rare
Cystecercus

Question 9

Taenia ovis

Answer 9

Cysticercus
Slaughterhouse rejection
Myocardium wnd diaphragm
Whitr nodules
Sheep dog
Eggs can be spread by flies

Question 10

Taenia saginata

Answer 10

Cysticercus
Cattle human
Little patjogenic significance
Calves infect by hands or older cattle by enviro
Assoc with poor human sanitation
Humans infect by eating raw or undercooked meat
ID by meat inspection of masseter muscles

Question 11

Taenia solium

Answer 11

Cysticercus
Human pig
Assoc poor sanitation
Cystercerci dev in himans too
Serious health risk

Question 12

Exhinicoccus

Hydatid

Answer 12

Oncosphere penetrate gut wall and carried via lymph to lungs or via blood to liver
Sudden death due to ruptures cyst and anaphylactic reaction
Zoonotic - life threatening

Question 13

Echinococcus multilocularis

Answer 13

Int rodents usually but can be ruminans
Def cats and dogs
Zoonotic by contact with contam fur uncooked veg
Larvae dev in liver as multilocular cysts
Concern about UK intro via dog importation
Pet passport scheme req tapeworm treatment before entry into Uk

Question 14

Cestode control

Answer 14

Burial
Prevent access to carcass and feed store by dogs
Treat farm dogs regukarly
Confine dogs before treatment

Question 15

Monezia

Answer 15

Int mites
Def shep
Small intest
Eggs released from segnebts before or after voiding
Oncosphere eaten by mites dev into cystercercoids
Overwinter in mites
disease incudence related to forage mite activity

Question 16

Anoplocephala

Answer 16

Int mites
Def horses
Jejunum
Ulcerate intest muc
Intestinal obstruction or perforation

Question 17

Dipylidium

Answer 17

Int fleas or lice
def dogs and cats
Larvae dev to cycercercoid in abdominal cavity
Complete life cycle when ingested in grooming
Freshly passed segments are active and crawl from anus
Oncospheres cont in egg packets
Common
Can cause itching
Small human infection risk