1. Parasitology is classified into three main groups
Protozology
(proto = primitive)
Study of protozoa
Helminthology
(Helminth = Worm)
Study of helminth
Entomology
Study of arthropods

2. Helminths (worms) are multicellular parasites.
Helminthology
Helminths
Helminths (worms) are multicellular parasites.
They are divided into:
1- Round Worms Flat Worms
(Nemathelminths) (Platyhelminths)
Class Nematoda
(Flukes) (Tape worms)
Class Trematoda Class Cestoda

3. Class
Trematoda

4. 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 3rd genital sucker.

5. 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)

6. Snail: Pirenella conica
1. Heterophyes heterophyes
Snail: Pirenella conica
Eggs: small, operculated, yellowish brown, thin shell (H.P)

7. Heterophyes heterophyes cont.
Pear shaped,
Very small size, (2mm)
Oral,ventral, genital suckers
Vitelline glands
2 testis, 1 ovary
simple intestinal ceaca
(L.P)

8. Heterophyes heterophyes cont.
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.

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

10. Fasciola hepatica Fasciola gigantica
Fasciola sp. cont.
Fasciola hepatica Fasciola gigantica
Less prominent shoulders, parallel margins, larger in size
cephalic cone, 2 shoulders, converging margins,smaller in size

11. Snail (Lymnae caillaudi)
Fasciola sp. cont.
Snail (Lymnae caillaudi)
Fasciola egg:very large, operculated, yellow, thin shell (H.P)

12. Fasciola sp. cont. 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.

13. Schistosoma sp. a. Schistosoma mansoni Schistosoma mansoni male:
8-10 mm, has gynacophoric canal, dorsal surface covered with tubercle (4X)
Schistosoma mansoni female: 14 mm, taller and thinner,vitelline glands occupy 2/3 of the body( 4X)

14. Schistosoma mansoni snail Biomphlaria alexandrina
a. Schistosoma mansoni cont.
Cercaria of Schistosoma mansoni : elongated head, biforked tail (H.P)
Schistosoma mansoni egg: oval with lateral spine (H.P)
Schistosoma mansoni snail Biomphlaria alexandrina

15. b. Schistosoma hematobium
Egg: oval with terminal spine (H.P)
Snail: Bulinus truncatus

16. Schistosoma mansoni
Schistosoma hematobium
Location
Veins of large intestine, colon (lower mesentric vein
Veins of urinary bladder (venous plexus of urinary bladder
Interm. host
Biomphalaria alexandrina
Bulinus truncatus
Diagnosis
Eggs in stool
Eggs in urine
Infective stage
Cercariae
Mode of transmission
Direct skin penetration of cercariae during swimming
Disease:
Intestinal Bilharziasis
Urinary Bilharziasis

17. Helminthology Questions form: Name and sex of the parasite
Class to which the parasite belongs
Location in the host
Intermediate host
Definitive host
Infective stage
Mode of transmission
Lab diagnosis
Disease