TREMATODES (FLUKES)
Hermaphroditic (both male and female reproductive organs in single body) Exception- schistosomes 1st intermediate host-mollusks (snails and clams) Eggs have operculum-allows larval worm to find the host (exception-schistosomes)
Types
Fasciolopsis buski Fasciola hepatica Opisthorchis sinensis Paragonimus westermani Schistosomes S.mansoni S.japonicum S.haematobium
FASCIOLA BUSKI
Giant intestinal fluke Largest, most prevalent fluke Intermediate host-snail Reservoir hostpigs,dogs,rabbits,humans Biologic vector-water plants
Life cycle
Infective stage- metacercaria Diagnostic stage- eggs in feces Free swimming larval stage-miracidium
Clinical features
Abdominal discomfort,diarrhoea Marked eosinophilia Worm takes up residents in the bile ducts,ther mechanical irritation and toxic secretions cause hepatitis,biliary obstruction etc Lab diagnosis Stool microscopy-large, golden,bile stained eggs with an operculum on the top DOC-praziquantel Proper sanitation measures
FASCIOLA HEPATICA
Sheep liver fluke Intermediate host-snail Biological vector-water plants Reservoir host-sheep, cattle, humans
Life cycle
Lab diagnosis and treatement same as that of buski
OPISTHORCHIS SINENSIS
Also called clonorchis sinensis/CHINEESE LIVER FLUKE Intermediate host-snail and fresh water fish Biologic vector-uncooked fish Reservoir host-dogs,cats, humans
Life cycle
Clinical features
Pain in the right upper quadrant over the liver,chills,fever, marked eosinophilia. Hepatitis ,portal cirrhosis, invades the bile duct
Lab diagnosis & treatment
Stool examination- unembryonated eggs Eggs are present in the bile also, unlike f.buski which is limited to small intestine Bithionol or benzimadazole compound triclabendazole are the drugs used Avoid uncooked acquatic vegetation
PARAGONIMUS WESTERMANI
Lung fluke Intermediate host-snail, fresh water crabs, Cray fish Biologic vectors-uncooked crabs, Cray fish Reservoir host-pigs, monkeys and humans
Life cycle
Infective stage-metacercariae in the fresh water crabs Larva hatches in the stomach and migrate Adult worm resides in the lungs Eggs from it released in sputum or feces
Clinical features
Onset coincides with larval migration-fever, chills and high eosinophilia When it reaches the lung-fever. cough and increased sputum-blood stained and dark with eggs(RUSTY sputum),chest pain
c/c infections lead to fibrosis of lung May invade brain and spinal cord-cerebral paragonimiasis Also invades subcutaneous tissue, abdominal cavity and liver
Lab diagnosis
Examination of sputum and feces-golden brown operculated eggs Chest xray-pleural effusions,cyst,infiltrates Eosinophilia
Treatment
DOC-praziquantel Avoid consumption of uncooked fresh water crabs Proper sanitation
SCHISTOSOMES(blood flukes)
S.MANSONI S.JAPONICUM S.HAEMATOBIUM Causes-schistosomiasis/bilhariasis/snail fever Separate male and female flukes Intermediate host-snail Reservoir host-rodents, domestic pets, live stock, humans
Eggs do not have operculum. Infective stage- cercariae S.mansoni and japonicum- mesenteric veins and produce intestinal amoebiasis S.hematobium – veins around the urinary bladder and causes vesicular schistosmiasis.
Life cycle
Clinical features
Earliest symptoms- penetration of cercaria though the skin- pruritic rash Onset of oviposition-katayama syndromefever,chills,cough,urticaria,arthralgia,lymphad enopathy,splenomegaly,abdominal pain cases- granulomas and fibrosis
S.MANSONI o
EGGSOval and have a sharp lateral spine. Dermatitis with allergic reaction,pruritis,edema In lungs-cough Liver-hepatitis
Intestinal-abdominal pain,diarrhoea,tenderness of liver c/c cases-hepatosplenomegaly with large accumulations of ascitic fluid in pleural cavity
Gross examination-liver-pseudotubercles (white granulomas) Clay pipe stem fibrosis- fibrous tissue reacting to the eggs in liver surrounds the portal vein in a thick and grossly visible layer
Lab diagnosis
Demonstration of eggs DOC-praziquantel Schistosomal dermatitis and katayama syndrome –treated with administration of antihistamines and steroids Improved sanitation
S.JAPONICUM
EGGS- spherical, tiny spine Clinical features same as mansoni Frequently involves the CNSgranulomas,lethargy,speech impairment, visual defects, seizures DOC-praziquantel
S.HAEMATOBIUM
Mainly in the Nile valley Develops in the liver and migrates to vesical,prostatic,uterine plexus of venous circulation Eggs-sharp with a terminal spine Eggs may be seen in urine Reservoir hosts-monkeys,baboons,chimpanzees
Initial features are similar to others But also has hematuria,dysuria,urinary frequency Develops obstructive uropathy in the end stage May show squamous cell carcinoma of bladder DOC- praziquantel
Cercarial dermatitis
Swimmers itch-non human cercaria produce dermatitis, but they cannot develop in the human host Can lead to secondary bacterial infection Treatment-oral trimeperazine, topical antihistamines