Trematodes

Question 1

What are the characteristics of trematodes?

Answer 1

Made of flukes and schistosomes
Hermaphroditic and operculated eggs except schistosomes
Disease is due to movement of worm and inflammatory reaction to eggs except F. Buski

Question 2

What are some of the flukes and schistosomes?

Answer 2

Fasciolopsis buski
Fasciola hepatica
Clonorchis sinensis
Paragonimus westermani, P kellicotti
Schistosoma mansoni, japonicum, haematobium

Question 3

What are the characteristics of fasciolopsis buski?

Answer 3

Also called Giant intestinal fluke
Found in SE Asia, India
Infection caused by ingestion of metacercaria on water chestnuts
Reservoirs are pigs and humans
Causes malabsorption syndrome
ID: 100 microns golden ,bile stained operculated eggs in fecal smears

Question 4

What are the characteristics of Fasciola hepatica?

Answer 4

Also called Sheep liver fluke
Widely distributed in sheep raising areas
Infection due to Ingestion of contaminated watercress
Route: intestine-liver-bile duct
Diseases: hepatitis, cirrhosis, biliary tract disease
ID: similar to F. Buski but eggs in bile also

Question 5

What are the characteristics of clonorchis sinensis?

Answer 5

Also called Chinese liver fluke
Found in Eastern Asia and immigrants from there
Infection due to ingestion of undercooked fresh water fish infested with metacercaria
Route:Intestine-liver-bile duct and gall bladder
Diseases: hepatitis, biliary obstruction leading to liver rot, pigmented gallstones
ID:operculated eggs with small apopercular knob

Question 6

What are the characteristics of Paragonimus westermani?

Answer 6

Called P.kellicotti in the USA
Causes Paragonimiasis due to undercooked crabs and crayfish, and pork
Reservoir: shore feeding pigs
Route: intestine-diaphragm-lung
Diseases: inflammatory disease of lung, liver, CNS
ID: operculated eggs in rusty sputum or feces

Question 7

What are the characteristics of schistosomes?

Answer 7

Found in tropical areas
S.mansoni-widespread
S. Japonicum-  oriental blood fluke
Both shed in feces
S.haematobium found in bladder, shed in urine
All are obligate intravascular parasites
Have both sexes
Non operculated eggs
Cercaria penetrate skin from water
Migrate to portal blood vessels

Question 8

What are the characteristics of schistosomiasis?

Answer 8

Cercarial itch
Snail fever/bilharziasis/schistosomiasis with granulomatous reaction in liver
Katayama syndrome at on set of egg production with fever, chills and cough

Question 9

What are some differences and similarities within the schistosomes?

Answer 9

S. Mansoni and S. Japonicum lay eggs in mesenteric vessels of bowel and rectum
Eggs circulate liver and exit in feces
Severely affect liver and spleen
S. Haematobium lay eggs in venous plexus of bladder, eggs shed in urine
Can cause fibrosis of bladder wall, hematuria, bladder carcinoma
S. Japonicum doesnt have a spine
S. Mansoni has a lateral spine
S.haematobium has a terminal spine