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Summary of medical parasitology 2
- 1. Medical Parasitology Second year Module8 Infection and Immunity By: ASM Team 2020
- 2. Medical Parasitology Helminths/worms - multicellular -bilaterally, symetrically elongated - flat or rounded Protozoa/unicellular - unicellular - free or parasetic - perform all life function
- 3. Protozoa Helminths Platyhelminths - leaf like -Alimentary tract rudimentary - no body cavity - Hermaphrodite Trematoda flukes Cestoidea Nematodes Sarcomast igophora Ciliophora Apicomple xa Protozoa
- 4. Leaf like Pear shapped Elongated Coveredby cuticle(smooth, spiny or tuberculated) 2 suckers(attach to cuticle) Three layers of muscle fibers Spongy tissue(internal organs) Anaerobic Feed on blood, intestinal contents, biliary secretions, tissue juices Life cycle of Trematodes: Digenetic(def host sexual Intermediate host(asexual)>>snails) Except bilharizia Digestive •mouth bottom of oral sucker, Pharynx •oesophegus •two intestine caeca Reproductive •hermaphrodites •except billharizia
- 5. Examples: Schistosoma mansoni, haematobium Flat Ribbonlike Segmented
- 6. Mm to m head,neck, proglottids(chain strobila) proglottids>> Mature(hermaphrodite), immature and gravid(at end of chain contain eggs) Neck is region of growth Cuticle >> absorb nutrients, protect against enzymes Life cycle of cestodes: Reproduction •self fertilization •cross Nervous •in scolex Mature In stools Cystic larval stages
- 7. Examples: Taenia echinocossus granulosus Unsegmetned Cylinderical Body cavityand alimentary canal Free in soil or water Tapered ends Cuticle(scleroprotein) Digestive •mouth anterior •anus posterior •cloacal (genital and digestive) in male
- 8.
- 9. Life Cycle ofnematods: (Ascaris lumbricoidis) Female lay their eggs(diagnostic stage) in the small intestine Fresh eggs are immature(2 weeks to mature(infective)
- 10. -Unicellular Microorganisms capableof performing ALL functions of life. -Vital functions are performed by the Protoplasm; Protoplasm Cytoplasm Ectoplasm; “outer layer” -Movement -Ingestion -Excretion -Secretion -Respiration -Protection Endoplasm; “Inner layer” -Digestion -Reproduction Endoplasm contains; -Nucleus - food vacuoles - Glycogen “stored food” - Contractile Vacuoles (Regulation of osmotic pressure) -Nucleus may be compact or vesicular Nucleoplasm Protozoa Phylum Sarcomastigophora A. Sarcodina (Amoeba) - two stages; -Trophozoites -cysts -Trophozoites move with pseudopodia. e.g. Entamoeba Histolytica. Pathogenic - lives in Large intestine causing Ulceration of the mucus membrane. The infective stage is the cystic form. B. Mastigophora (Flagellates) e.g. Trypanosomes (Blood Flagellates) two species, -African -American live outside the RBCs. (need insect vector) Phylum Ciliophora (Ciliates) -they Divide sexually and asexually -they possess contractile Vacuoles -they Divide sexually (Binary fession)and asexually (conjugation). e.g. Balantidium coli Phylum Apicomplexa -No definite organ of locomotion. -they possess an apical complex
- 11. Immunological responses againstparasites Innate immunity(non-specific) Acquired immunity(specific) 1-Innate immunity Mechanical barriers(skin,mucus membrane&nasal hairs) chemical barriers(gastric HCL kill Amoebic trophozoites) genetic factors(Plasmodium malaria use the Duffy antigen receptors to enter RBCs) cellular components(macrophage) inflammatory response(fibrin deposition) Complement (the most important is C3, here activated by nonspecific binding of the complement to the surface of a microorganism) (alternative pathway). 2-Acquired immunity immune cells(T &B lymphocytes,Macrophage,neutrophils&eosinophils) soluble mediators(anti bodies&cytokines) complement(activated by immune complex) tissues(bone marrow,thymus&lymph nodes) produce&store the immune cells The consequences of complement activation lysis of target cell coating of parasites to be phagocytosed attraction of phagocytic cells(macrophage&neutrophils) Type of acquired immunity cellular immunity(by T lymphocytes, Macrophage, Neutrophils& Eosinophils) humoral immunity(byB lymphocytes,IgM,IgA&IgE) Antibody Dependent Cellular Cytotoxicity(ADCC) ByIgE, IgG, Ag_Ab reaction, Macrophage. Neutrophils, Eosinophils& platelets e.g. Plasmodium and Toxoplasma gondii -plasmodium (Malaria) lives inside the RBCs. needs insect vector. -Toxoplasma gondii involves two hosts Man and other animals (intermediate hosts) and Cats (definitive host)
- 12. immune mechanisms insome parasitic infection A) By the host 1- antibodies destroy the parasite membrane as plasmodium sporozoites,damage trypanosoma & intestinal worms. 2-neutralization antibodies block the parasite binding receptors to prevent further multiplication as plasmodium sporozoites &toxoplasma. 3-expulsion of intestinal worms >T helper 2 (Th2) secrets IL4&IL5 that stimulate B lymphocytes to produce anti bodies which enter the gut lumen to kill them and to act on intestinal smooth muscles to facilitate the process >the nonspecific inflammatory process make the macrophage secrete the cytokines which secrete mucus that coat the worm 4-cellular immunity granuloma in schistosoma infection B) BYthe parasite 1-avoidance of intra cellular destruction antibodies affect only the extracellular parasites as in plasmodium malaria live in RBCs&toxoplasma enter the cell actively into a membrane bounded vacuole(endosome) 2-antigenic variation the parasite change the Variable Surface Glycoprotein(VSG) when the recognize it as the african trypanosomes so this parasite become antigenically different from the previous ones 3-hiding from immune attack > as adult schistosomes by incorporating host antigen onto their surface >the fibrous capsule around a hydatid cyst >entamoeba histolytica form a cyst wall 4-withstanding the immune attack cestodes &nematodes have a thick cuticle for protection immunopathological consequences 1) the T cell dependent granulomas around eggs of schistosomes in the liver contribute much to the pathology of the disease 2) immune complex may be deposited in the organs causing pathological changes as in kidney by plasmodium infection 3) the hydatid cyst contain highly allergic fluid which will cause anaphylactic shock if it leaks 4) in an immunocompromised patient such as in an AIDS patient ,toxoplasma dormant organism are reactivated and cause death of the patient
- 13. Arthropods General features: Adult(male and female) femalelays eggs or larva develop by two ways(complete or incomplete metamorphosis) Antenna Chitinous exoskeleton Invertebrate Mouth Parts Bilaterally symmetrical Wings(هنا باينه مش الجناحات (معلش ) Body cavity(haemocele) Contain clear colorless haemolymph
- 14. Larva is toodifferent from adult Incomplete metamorphosis Adult=larva But differs in: Size(larva smaller) Larva sexually immature
- 15. Medical importance ofarthropods: :بتتنقل بقي ازاي Causative agent - lesion in tissue( scabies-myasis) - toxin/venom through bite or sting - Allergy saliva of blood sucking mosquito - Entomophobia neurosis Vector Mechincal -transfer on or in their body unchanged e.g House fly Biological have a role in life cycle Propagative multiply in it e.g. yerisinia pestis in fleas cyclodevelo pment morpholog y developme nt microfilaria in mosquito cyclopropag itive both morphology and number plasmodia in female anophelous Crushing on skin(typhus by lice) Vomit drop -non blood sucking on food(enamoeba) - blood sucking in blood meal(leishmania) Coxal fluid during feeding fluids from coxal gland(relapsin g fever) Salivary secretion blood meal(malaria)
- 16. Classification of Arthropods 1-Class Crustacean: (Cyclops) aquatic microorganism Pyriform body Anterior broad cephalothorax Five pair of legs Bristle Narrow four segmented body
- 17. 2- Arachnida: landarthropods Scorpionida>> Four pairs of legs CephalothoraxSegmented abdomen Telson ends in stinger that secretes venom
- 18. Clinical Picture ofscorpion bite: immediate intense aching pain burn sensation at bite site Lymphadentitis Numbness Throbbing Twitching sweating excess salivation
- 24. Scarpotes Scabiei (itchmite) morphology life cycle
- 25. Clinical pictures ofscabies 1- sites))) iner-digital-flexor of arm-breast-ambilicus-sholder- back -buttocks 2- burrows excauvated by fertilized female in epidermis with exterb=nal opening 3- they deposit fecal pellets which lead to vesiculation of the skin -----> puritis indused by warmth and perspiration 4-nocturnal itching 5- irritation caused by acidic secrtion 6- 2th bacterial infection and pustule formation complicate lesion Diagnosis :-
- 26. treatment :- 1- scrubbbedthe infected part by soap and warm water with lifa 2-permethrin 5%------->week 3-euraxolotion ------->5days 4- boil patient clothes and bed sheets. House dust mites