Parasites 1

Question 1

Taenia Saginata

Answer 1

Transmission

Ingestion of undercooked cows

Stays in the small bowel and mature, tail end segments are proglottids and contain embryonated eggs. Proglottids detach and pass in to environment

Cattle eat them up with vegetation that is contaminated.

Eggs hatch and penetrate into muscle as oncospheres which develop into cysticerci in muscle to be eaten by more humans

Question 2

Taenia Solium

Answer 2

Transmission

Ingestion of undercooked pig

Develop in bowel, have proglottids which are pooped out, taken up by pigs.

Oncospheres develop and lodge into muscle as cycticerci in pig muscle.

Cycticerci may develop in any organ! Including the brain and cause major problems. Cysticercosis!

Diagnosis

Cysticercosis by x ray, CT/MRI or serology

Immunity
Humoral immune response

Treatment
Praziquantel, Niclosamide or albendazole
Dexamethasone to redure inflammation especially in neurocysticercosis

Question 3

Diphyllobothrium Latum

Fish Tapeworm

Answer 3

Transmission
Ingestion of undercooked fish with plerocercoid larvae

Pathology
Similar to taeniasis
Vitamin B12 deficiency

Diagnosis
Ovoid, operculated, non-embryonated eggs,
Proglottids
Pernicious anemia and fish diet

Treatment
Praziquantel or Niclosamide

Question 4

Echinococcus Granulosus

Answer 4

Transmission
Ingestion of eggs from dogs living in close contact with humans

Epidemiology
Pastoral Cycle, grazing livestock like sheep in contact with dogs
Dogs who are allowed to EAT internal Organs
Wild canines

Pathology
Cystic Echinococcosis **Hydatid Disease, mainly in the liver and lungs (maybe in the CNS)
Latent up to 20 years, when cysts rupture causes pain and then seeding new sites
Anaphylaxis after rupture can be fatal

Diagnosis
CT/MRI, Ultrasound, looks like a slow growing tumore
serology

Immunity
Circulating antibodies against cyst antigens
Host may limit cystic larval development

Treatment
Surgery avoiding cyst rupture
laparoscopic surgery with aspiration and filling with hypertonic saline
Chemotherapy with albendazoleor mebendazole; low cure rate

Prevention disposal of livestock Offal
Deworm dogs

Question 5

Echinococcus Multilocularis

Answer 5

Same basic life cycle as E. granulosus

Definitive host: fox, coyote, wolf, but also dog and cat
Intermediate host: rodents (mice, voles, shrews), human

Transmission
by ingestion of eggs

Alveolar echinococcsis
larvae produce small, not fully mature cysts in liver that mimic carcinoma; cysts often spread to other organs
Fatality rate up to 75% if untreated

Diagnosis
Imaging and serology

Treatment
Radical Surgery and Mebendazole, Albendazole

Prevention
avoid stray dogs

Question 6

Types of Schistosoma

Blood Flukes

Answer 6

S. haematobium
Venous plexus of bladder
Eggs in Bladder

S. mansoni
Inferiormesenteric veins
Eggs in Large intestine

S. japonicum
Superior mesenteric veins
Eggs in Small intestine

Question 7

Schistosomiasis

Answer 7

Transmission
Invasive aquatic, can penetrate the skin

Pathology
Rash from invading cercaria

Delayed symptoms
From Migrating Schistosomula and egg deposition (immune response to eggs)
Katayama syndrome (fever, cough, chills, myalgia eosinophilia)

Chronic Symptoms
Related to eggs lodged in intestine, liver of bladder (s.h.)

Strong inflammatory response with granuloma formation

S.m., S.j.: severe liver disease (periportalfibrosis), portal hypertension, hepatosplenomegaly, bleeding esophageal varices; liver and colon cancer

S.h.: fibrosis of the bladder, scarring, loss of bladder function; bladder cancer

Diagnosis
Eggs in stool or urine, serology

Treat
Praziquantel