Parasitic Helminths and Arthropod Agents and Vectors of Diseases

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

Location of helminths in the body: Intestinal helminths: Tissue helminths:

Nematodes General features : 1. Elongated worm, cylindrical, unsegmented and tapering at both ends. 2. Variable in size, measure from less than <1 cm to about 100cm. 3. Sex separate and male is smaller than female

Ascaris lumbricoides (roundworm)

The commonest human helminthes infection. Found in jejunum and upper part of ileum. Female about ± 20 cm which is longer ± 10 cm than male. Feed on semi digested food In the small intestine. Ascaris lumbricoides (roundworm)

Ascaris lumbricoides

The Trematodes Leaf- like un-segmented

Taenia saginata Example of a tapeworm (cestodes, tape –like,segmented)

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: - cyclical - propagative - cyclo-propagative III: Trans-ovarian transmission

Scabies as etiological agent of the disease ( الجرب ) tissue damage

World- wide distribut ion Body with 3 visible parts, 3 pairs of legs 1 pair of visible wings. Retract ed mouth parts Breeds in soil and dirt Not a blood sucker. Mechani cal transmi ssion of many disease s : viruses, bacteria and parasite s HOUSE FLY

Myiasis (( التدويد

Ophthamo-myiasi s

Mosquitoes : Cosmopolitan, more than 3000 species.. Genus and species distinguished by morphology of adult and developmental stages.

Phlebotomus ( sand fly)

Rat flea Flea البراغيث

LICE القمل Louse(singular), Lice (pleural) Pediculus humanus

Bed bugs البق (Cimex lectularius)

Bee BEES Venoms of bees are a mixture of enzymes and several polypeptides some of which are pharmacologically active e.g. histamine or neurotoxic. Some people are hypersensitive to venoms and suffer anaphylactic reaction, death might result in 1 hour.

Highly venomous Thick-tail scorpions (family Buthidae). They have thick tails and thin pincers. Scorpions

Scabies mites ) السوس )

Scabies

(The Spider): This spider is commonly found outdoors and around human habitation. It's often called The Red-back spider.. Hobo or Brown Recluse Spider: A venomous bite from a can cause severe necrotic arachnidism results from envenomation (venom poisoning). It occurs due to the venom's ability to clot blood that results in an area of tissue receiving inadequate blood flow and thus dying secondary to oxygen starvation.

TICKS Body 1 segment 4 pairs of legs no antennae no wings Hard Ticks: Vector for: Babesiosis, Q fever, Rocky Mountain spotted fever Soft ticks: Vector for: Relapsing fever

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

Parasitic Helminths and Arthropod Agents and Vectors of Diseases Objectives: By the end of this lecture the student should be able to : Name the three main groups of parasitic helminths and their characteristic morphological features. Describe the life cycle of Ascaris lumbricoides as an example of parasitic heminths. Discuss the role of arthropods as agents and as vectors of diseases in humans. Give examples of the main arthropod vectors of diseases.