Class Trematoda

General characters Flat worms (no cavity),not segmented, bilaterally flattened (except Schistosoma is cylindrical) Hermaphrodite (except Schistosoma) Body has 2 suckers for attachment :oral, ventral,(except Heterophyes has a 3 rd genital sucker

General characters Life cycle show sexual phase (defenitive host) and asexual phase (intermediate host) Require one or more intermediate host 1st intermediate host is a snail Eggs have an operculum Infective stage is encysted metacercaria (except schistosoma: cercariae)

Heterophyes heterophyes Heterophyes heterophyes adult Heterophyes heterophyes eggs: Heterophyes heterophyes snail Heterophyes heterophyes encysted metacercaria Heterophyes heterophyes in small intestine

snail: Pirenella conica Eggs: small, operculated, yellowish brown, thin shell (H.P)

pear shaped, very small size, (2mm) oral,ventral, genital suckers vitelline glands 2 testis, 1 ovary simple intestinal ceaca (L.P)

Heterophyes heterophyes adult in small intestine Adult worm is present in intestinal villi

Heterophyes heterophyes encysted metacercaria in Bouri and Bolti muscles

Heterophyes heterophyes Location of adult: small intestine Intermediate host: Primary: Pirenella conica Secondary: Bolti and Bouri fish Infective stage: encysted metacercaria Mode of transmission: ingestion of raw fish containing encysted metacercaria Diagnosis: eggs in stool Disease: heterophiasis

Fasciola Fasciola hepatica adult Fasciola gigantica adult Fasciola gigantica snail: (lymnaea cailliaudi ) Fasciola egg

OS: oral sucker VS: ventral sucker OV: ovary TE: testis Vi: vitelline glands UT: uterus INC: intestinal caeca GP: genital pore

Fasciola hepatica Fasciola gigantica Less prominent shoulders, parallel margins, medial branches are T or Y shaped, larger in size cephalic cone, 2 shoulders, converging margins, simple medial branches of intestinal caeca,smaller in size

Snail (Lymnae caillaudi) Fasciola egg:very large, operculated, yellow, thin shell

Location of adult: bile duct Intermediate host : primary : snail Lymnaea truncatula for F.hepatica and Lymnaea. cailliaudi for F. gigantica secondary: leaves of fresh-water plants Mode of transmission: ingestion of raw water-cress containing encysted metacercariae Infective stage: encysted metacercaria Diagnosis: eggs in stool Disease: Fascioliasis

Schistosoma sp. Schistosoma mansoni male Schistosoma mansoni female Schistosoma mansoni male&female Eggs of Schistosoma mansoni Eggs of Schistosoma haematobium Snail of Schistosoma mansoni Snail of Schistosoma haematobium S.mansoni cercaria

S. mansoni S. mansoni male:8-10 mm, has gynacophoric canal, dorsal surface covered with tubercle S. mansoni female:14 mm, taller and thinner,vitelline glands occupy 2/3 of the body S.mansoni male&female

S. mansoni snail Biomphlaria alexandrina S. mansoni egg:oval with lateral spine Cercaria of S.mansoni: elongated head, biforked tail S. mansoni snail Biomphlaria alexandrina

S. Hematobium Egg: oval with terminal spine Snail:Bulinus truncatus

S.mansoni S.hematobium Location:veins of large intestine, colon (lower mesentric vein Intermediate host:Biomphalaria alexandrina Diagnosis: eggs in stool Infective stage: cercariae Mode of transmission:direct skin penetration of cercariae during swimming Disease: Intestinal Bilharziasis veins of urinary bladder (venous plexus of urinary bladder) Bulinus truncatus Eggs in urine Cercariae direct skin penetration of cercariae during swimming Urinary Bilharziasis