Parasitology Lecture 16 - Blood Flukes.pdf

BLOOD FLUKES

Dr. Cabudoy

Note: Italicized text were taken from the manual BLOOD FLUKES  

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Superfamily Schistosomatoides Major source of morbidity and mortality for developing countries o Africa o S. America o Carribean o Middle East o Asia Disease caused: Schistosomiasis, Bilharziasis Medically Important: o Schistosoma haematobium o Schistosoma mansoni o Schistosoma japonicum 1st INTERMEDIATE HOST: Snail 2nd INTERMEDIATE HOST:None DEFINITIVE HOST: Man EGG: Mature, Non operculated SEX: Dioecious FREE SWIMMING LARVA: Forktailed Cercaria DEVELOPMENT: S1 – S2 -C INFECTIVE STAGE: Cercaria DIAGNOSTIC STAGE: Egg Peculiar Flukes Mature in blood vascular system in Definitive Host Calcified egg of S. haematobium in Egyptian mummies “Split body” – gynecophoral canal of male; where female lodge during copulation S. japonicum – lays the most number of eggs MALE = Shorter, stouter, no pharynx, with strong oral sucker FEMALE = long, slender “Romancing parasite” – once they copulate, tey won’t separate anymore Adult live in veins Previously called BILHARZIA Adults live in veins that drain certain organs  paired worms go upstream into smaller veins where female deposit eggs  eggs traverse wall of venule  eggs traverse intervening tissue  traverse gut/bladder mucosa  expelled from host  FECES or URINE SCHISTOSOMA HAEMATOBIUM

ADULT 

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Male o o o o

EGG

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Ovary is posterior to the mid portion of the organism With oral and ventral suckers Shorter and stouter with a gynecophoral canal Cuticle has fine tuberculation With 4-5 large testes in cluster

Shape is elongate, ovoidal with thin shell and terminal spine Contains ciliated embryo SCHISTOSOMA MANSONI

ADULT 

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EGG

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Female o Long and slender with oral and ventral spines o Ovary is anterior to the mid-portion of the organism Male o With oral and ventral suckers o Shorter and stouter with a gynecophoral canal o With 6-9 small testes in column or group shape is elongate ovoidal with thin shell and lateral spine contains ciliated embryo SCHISTOSOMA JAPONICUM

Female o Long and slender with oral and ventral suckers

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BLOOD FLUKES

Dr. Cabudoy

Note: Italicized text were taken from the manual ADULT 

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EGG

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Female o Long, slender, with oral and ventral suckers o Ovary is centrally located Male o With oral and ventral suckers o Shorter and stouter with gynecophoral canal o Cuticle has no tuberculation Shape is ovoidal or subglobular, with thin shell, rudimentary or abbreviated lateral spine and cellular debris attached to the shell Contains ciliated embryo

EGGS (3 species)  Causes infection/symptoms  Form pseudotubercles microscopically  Marked eosinophilic reaction surrounding eggs  Multinucleated giant cells  Have antigenic properties – depend on host variability cause granuloma  S. japonicum and S.mansonia eggs in the liver and intestine o Intestine: fibrosis in mucosa  malabsorption  mucoid, bloody diarrhea o Liver: fibrosis  cirrhosis LIFE CYCLE

OVA in feces  MATURE when laid hatch in water (to look for Intermediate Host)  Release MIRACIDIA  penetrate SNAIL  SPOROCYST  NO REDIA STAGE  CERCARIA goes out into the water  SKIN PENETRATION

(enzyme mediated penetrance to skin)Attracted to AA ARGININE  penetrate skin and disappear in 10-30s  LEAVES TAIL BEHIND SCHISTOSOMULAE (without tail)  enter peripheral circulation  migrate to portal blood in liver and mature into adult  paired worm go upstream into smaller veins where female deposit eggs  eggs traverse wall of venules (aided by spine)  traverse intervening tissue  right heart pulmonary  left heart systemic  liver and pair up  travel in pairs  migrate to wall of urinary bladder and GIT and lay eggs *Unpaired female don’t sexually mature; starving growth, stimulation for function is the male class PATHOGENESIS:  Unusual  Due to EGGS, not adult worms ACUTE SCHISTOSOMIASIS  Katayama Fever  Serum-like sickness that develops several weeks after exposure  Corresponds to the 1st cycle of egg deposition and is associated with marked peripheral eosinophilia and circulating immune complexes  It is most common with S. japonicum and S. mansoni infection and is most likely to occur in newly infected individuals after primary infection  Signs and symptoms usually resolve over several weeks but can be fatal to very young and very old  Mild maculopapular lesion, high grade fever CHRONIC SCHISTOMIASIS  More common  Result from egg-induced immune response, granuloma formation and associated fibrotic changes  Schistosomal eggs are highly immunogenic and induce vigorous circulating and local immune response EGG RETENTION AND GRANULOMA FORMATION in the BOWEL WALL (S. mansonia and S. japonicum)  Bloody diarrhea  Cramping  Inflammatory Colonicpolyposis  Increased rate of recurrent Salmonella infection  Heavy infection  Hepatic Disease  Severe Fibrosis  Pipestem pattern  Periportal Fibrosis  portal HPN  Portal HPN sequelae: o Splenomegaly o Ascites o Esophageal varices o Development of portosystemic collaterals EGG RETENTION (S. haematobium)

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BLOOD FLUKES

Dr. Cabudoy

Note: Italicized text were taken from the manual     

PHYSICAL  Vary with stage of illness, worm burden, and endorgan involvement

Hematuria Dysuria Ulcer Bladder polyp Obstructive uropathies

STAGES OF SCHISTOSOMIASIS STAGE 1  Invasion o Early infection, mild signs and symptoms o Skin penetration o Papulodermatitis due to fork tailed cercaria o Schistosomial dermatitis  Migration o Fever, cough o Inflammatory reaction to lungs and liver  Diagnosis o Cercaria Huellen reaction  Skin test (+) at stage 1  Non-specific STAGE 2  Maturation o From migration to penetration of egg o Katayama fever: early fever in schistosomial infection  Acute febrile response STAGE 3  Stage of Established infection o Massive egg laying o Early chronic infection, granuloma formed by egg

due

to

STAGE 4  Late infection and complications  Prolonged infection, marked decrease in egg production and extrusion of eggs or no eggs at all  Possible development of sequelae such as cor pulmonale, obstructive uropathy and formation of varices  Progressive fibrosis relative to infection  Involves brain in S. japonicum infection  Liver fibrosis  liver cirrhosis  portal hypertension  ascites, splenomegaly (due to direct invasion of eggs, portal hpn, and granuloma formation  Cachexic patient with big abdomen SQUAMOUS CELL CA  Most common cancer in Schistosomiasis TRANSITIONAL CELL CA  Most common type of cancer in Bladder CA

DIAGNOSIS S. japonicum and S. mansoni  Stool Exam  Serology o ELISA – helpful in confirmation of past exposure o Schistosomal atigen test to help distinguish between active and inactive infection o Antigen titers from serum and urine correlate with degree of infection  Rectal Biopsy  Kato-Katz – thick smear clarified with glycerol; for identification and quantification of ova in feces  Immunodiagnostic tests o Circum-oval precipitin test (COPT) o Cercaria Huellen Reaction(CHR) o Fluorescent Antibody test for cercaria (FAT) o ELISA  Ultrasound – to detect pipestem fibrosis of the liver and patency of the portal, splenic and superior mesenteric vessels S. haematobium  Urine Examination – (+) eggs  definitive diagnosis; 24-hour urine collection may be recommended  Micropore filtration for the detection of ova in urine  Cytoscopy  Immunodiagnostic tests o Circum-oval precipitin test (COPT) o Cercaria Huellen Reaction(CHR) o Fluorescent Antibody test for cercaria (FAT) o ELISA  Ultrasound – to detect urinary tract lesion TREATMENT  DOC: Praziquantel (Biltricide)  Anti inflammatory drugs SWIMMER’S ITCH  Schistosoma cercarial dermatitis BIRD’S SCHISTOSOME  Cercaria release allergens  Inflamed pus-filled pimple  Die in subcutaneous tissue cause allergy  severe manifestation  abscess

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BLOOD FLUKES

Dr. Cabudoy

Note: Italicized text were taken from the manual

Disease caused

S. haematobium Vesical schistosomiasis

S. mansoni Manson’s intestinal schistosomiasis

# of testes Uterus

4-5 Least eggs

6-9 Few

Eggs

Short, spine

Sharp, spine

Habitat

Urinary bladder plexus

Snail

Bullinus, Biomphalaria, Physopsis

Infection

Least serious

Distribution

Africa (Egypt)

Africa, SA

Excreted in

Urine

Feces

Male Morphology

Short, stout, gynecophoral canal present, cuticle tuberculation Ovary post-mid portion

Short, stout, gynecophoral canal present

Female Morphology

terminal

lateral

Large intestine, inferior mesenteric Biomphalaria (Africa, KSA, Middle East), Tropicorbis centrimetralis (Brazil)

Ovary ant-mid position

S. japonicum Oriental blood fluke, Schistosomiasis japonica 7 Most eggs ~300 Rudimentary, abbrev spine with cell debris Small intestine, superior mesenteric Oncomelania quadrasi

Most serious (most number of eggs) SEA, Philippines Urine and Feces Short, stout, gynecophoral canal present, no cuticle tuberculation Ovary centrally located

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