1. Classification of Parasites
helminths
Protozoa
Mulicellular
Specialized cells
Unicellular
Single cell for all function
Round worms
(Nematodes) cylindrical,
unsegmented
Flat worms
1-Trematodes:
leaf-like, unsegmented.
2-Cestodes:
tape-like, segmented
Amoebae:
move by psudobodia.
Flagellates:
move by flagella.
Ciliates :
move by cilia
Apicomplexa
(sporozoa) Tissue
parasites

2. Nematodes General features:
Elongated worm, cylindrical, unsegmented and tapering at both ends.
Variable in size, measure <1 cm to about 100cm.
Sex separate and male is smaller than female

3. Intestinal
Parasitic nematodes
Blood and tissues

4. Examples of Diseases caused by nematodes
Intestinal
Disease
ascariasis
Ascaris lumbricoides
blood and tissues
Disease
elephantiasis
Wuchereria bancrofti

5. Ascaris lumbricoides (roundworm)

6. Ascaris lumbricoides

7. LYMPHATIC FILARIASIS (elephantiasis)

8. The Trematodes

9. Schistosomiasis ( Bilharzia)
Example of diseases caused by trematodes.
Caused by:
Schistosoma mansoni ( intestinal schistosomiasis )
S. japonicum : intestinal
S. haematobium : urinary schistosomiasis

10. Life cycle of schistosomes

11. Tapeworms
(Cestodes)

12. Life cycle of Taenia saginata

14. MEDICAL IMPORTANCE OF ARTHROPODS
1)As aetiologic agents (causes) of diseases.
Tissue damage
Induction of hypersensitivity reactions.
Injection of poisons
Entomophobia (acarophobia)
2) As vectors of diseases:
I: Mechanical transmission - simple carriage of pathogens.
II: Biological transmission:

15. Important arthropod vectors for human diseases
House fly (Musca domestica)
Mechanical transmission of many viruses, bacteria and parasites.
Mosquitoes
Anopheles :malaria filariasis Culex: filariasis, viruses
Aedes: yellow fever, dengue fever, Rift Valley Fever
Lice
Body louse: vector for: Relapsing fever, typhus and trench fever.
Fleas
Rat flea is vector for plague due to Yersinia pestis.
Ticks
Soft ticks , some are vectors for : Borrela duttoni Hard ticks Include vectors for Babesiosis (protozoa), Q fever, and Rocky mountain spotted fever :
Tse tse fly (Glossina)
Vector for African Trynanosomiasis (African sleeping sickness)
Black fly (Simulium)
Vector for Onchocerca (river blindness)
Sand fly (Phlebotomus)
Vectors for leishmania and sandfly fever virus.
Cyclops
Vector for Dracunculus medinensis