Exam: 70?75 questions, multiple choice Trematodes ? Blood Flukes Genus: Schistosoma Live in veins of DHi. Common name: blood flukea. Cause schitosomiasis (aka bilharziasis, or snail fever)b. Schistosoma mansoni; Smi. Schistosoma haematobium; Shii. Schistosoma japonicum; Sjiii. 3 species of blood flukes that cause disease in humansc. 2nd to malaria in terms of importancei. 250 million people are infected worldwided. Separate male and female1) Dioeciousi. Live in blood vesselsii. Non operculated eggsiii. No rediae stageiv. No metacercarial stagev. Only human trematode that is not food bornvi. Major differences between schistosomas and other trematodese. Introduction ? NTDI. Schistosoma mansoni Schistosoma haematobium Schistosoma japonicum i. Beats cilia rapidly1) Miracidium spins inside egg2) Suture ? line along eggshell ? ruptures ? miracidium escapes3) Hatching: fresh H2O stimulates miracidiumii. Egg ? no operculuma. Female or male gender is definedi. Infects snailii. Miracidiumb. Peptide normally produced by snaila) Parasite causes snail to overproduce schistosecimb) Interferes with snail neuroendocrine systemc) Reproductive organs shrink and become snalld) Decreased egg production by snaile) Schisatomin1) Parasitic castrationi. Sporocyst ? Daughter Sporocystc. No Rediaed. Mouth1) Digestive tract2) Escape: exit snaila) Post?acetabular mucus ? attachmentb) Pre?acetabular enzymes ? penetrates host skinc) Head?function in adjustment after penetrating DHd) Glands3) Headi. Tail ? swimii. Cercariaee. Life CycleII. Lecture 4 Monday, September 28, 2009 6:36 PM Human Parasitology Page 1 Loses tail1) ? schistosomulumi) Important in protecting against hypoosmotic environment of fresh H2Oa) Loses glycocalyx2) Once cercariae penetrates DHiii. Get into bloodstream1) To lungs via blood2) Live in pulmonary capillaries3) Feed on RBC's4) Young adults ? migrate into systemic circulation5) Inside DHi. Schistosomulumf. Stays there till it reaches sexual maturity1) Mates2) Pairs migrate to venules of meseutery (membrane suspending organs)3) Migrate to hepatic portal veins in liveri. Lifespan: 10?30 yearsii. Oral sucker: surrounds mouth1) Ventral sucker2) No pharynx3) Bifurcatesa) Then joins together in posterior to form single cecumb) Cecum4) Dioecious5) Male shorter and stouter than femalea) Sexually dimorphic6) Schisto = splita) Soma = bodyb) Thinner female is held in canalc) Continuous mattingd) Male ? gynecophoral canal7) Unpaired female does not become sexually mature8) Morphologyiii. Adultsg. Sizea. Male Female Sj 20 mm 26 mm Sm 10 mm 14 mm Sh 15 mm 20 mm Sj ? smooth tegumenti. Sm + Sh ? tubercles (bumps) on surfaceii. Male ? Tegumentb. Sh ? 30 epd (eggs per day)i. Sm ? 200?300 epdii. Sj ? 3500 epdiii. Female ? Egg Productionc. Sh ? veins of urinary bladderi. Sm ? veins of large intestineii. Sj ? veins of small intestineiii. Habitat of Adults in DHd. Differences between the 3 Schistosoma SpeciesIII. Molecular mimicry- Absorb lipoproteins from host serum onto tegument- Worm looks like host- Resistance to reinfection- Schistosomulum in bodya. Host antibody produced kill some schistosomulumb. Molecular mimicryi. Host antibodies present, but do not attack adultsii. Adults developc. Destroyed by antibodies from original infectionsi. Any new schistosomulumd. Avoidance of Immune Attack IV. Pair (male & female) works upstream into smaller vesselsa. Female, working by herself, burrows into even smaller vesselsb. Female lays eggsc. Male: blocks blood flow to help eggs stay in placed. Female migrates back to malee. Actively move over egg1) Excludes egg from vein lumen2) Endothelial cells lining vessleli. Releases SEA (soluble egg antigen)1) Miracidiumii. Eggs must get out of vessel and into intestinal/bladder lumenf. Exit of Eggs from DHV. Human Parasitology Page 2 Enzymes- Proteins- Carbohydrates- SEA leaves through pores in eggshella) Eosinophilsa) Macrophagesb) Motile cells1) SEA stimulates granuloma to form around eggiii. Granuloma moves across wall to gut/bladder lumen and carries eggiv. 2/3 of eggs do not make it out of host1) Granuloma cells disperse and egg shedv. Allergic reaction ? itchy rash1) Penetration by cercariae into skini. Cercarial dermatitisa. Sm & Sji. Heavy infection and initiation of egg productionii. High fever1) Muscle pain2) Enlarges liver and spleena) Hepatosplenomegaly3) Immunology not understood- Symptomsiii. Acute disease ? Katayama Feverb. Buildup of calcified eggs leads to compromising of gut/bladdera) In gut/bladder wall ? Calcify1) Other eggs ? Bloodstream2) Egg entrapment i. Eggs are antigenic ? SEA- Granuloma ? protection from toxic substances- Costly ? pathology- Examples- Liver: Symmer's Pipestem Fibrosis: normal liver function is impaireda. Allows back pressure of urine to reach kidney ? Kidney Failurea) Sh: fibrosis of ureters and bladderb. Granulomatous responseii. Sh infections = ? bladder cancera. Sm infections = ? colon cancerb. Schistosoma infection may cause canceriii. Main Pathology ? eggsc. PathologyVI. Male menstruationa. Hematuria ? blood in urinei. Sh ? eggs in urine and fecesa. DiagnosisVII. Majes worm vulnerable to immune response since worm is no longer protected by the lipoproteins absorbed by the tegument a. Resistance is being developed by wormsb. Damages tegumenti. Praziquantela. Damages tegument, cecum, and vitelline glandsi. Artemethesb. TreatmentVIII. Chemotherapy and vaccinationa. Antigens are parasitei. Uses them as vaccine antigena. Human should develop a immune response in the event of infectionb. Takes Muscle proteins and enzymes that are unique to parasiteii. Parasite enzyme antioxidanta. Defense mechanism against reachie (sp???) oxygen speciesb. 40 ? 60 % reduction in worm burdenc. Inhibitory effect on egg productiond. No cross reactivy with human GSTe. Testing of safety and efficacyi) 100?300 liumausa) Phase II clinical trialsf. Glutathione?S?transferase (GST)iii. Most candidate vaccineb. Vaccine DevelopmentIX. Druga. Sewage Treatmentb. Snail Controlc. Boots and rubber Glovesd. Educatione. Vaccinef. Bill and Melinda Gates Foundation: provides PZQ to sub?saharan Africa for treatment of i. Schistosomiasis Central Initiativeg. CentralX. Human Parasitology Page 3 schistosomiasis _____________________________________________________________________________________ Cestodes Class Cestoideai. Order Cyclophyllideaii. Order Pseudophyllidea Phylum platyhelminthesa. Tapewormsb. All parasitesc. Digestive tract of some vertebrate host- IntroductionsI. Fig. 12?1- Scolex ? anterior end- Neck ? immediately posterior to scolax- Strobila ? rest of body- Neural gangliaa. Detects chemical and physical stimulia) Sensory endings on surfaceb. Nervous Structuresi. Attach to host's intestinal wall- Suckers: prominent in tapeworm species- Cyclophyllideaa) 4 muscular cupsb) Acetabulate suckersa. Attachment structuresii. Scolexa. Morphology ? AdultII. Muscular One. ProtrusibleTwo. Hooks on rostellumi) May have acessory holdfast structuresc) "Armed" rostellum Pseudophyllideaa) 2,4, or 6 bothriab) Shallow groovesc) Bothriate Fig 13?3ab. Posterior to scolexi. Undifferentiated zonea. Gives rise to proglottidsb. Contains stem cellsii. Process by which proglottids form at necka. Strobilationiii. Treament for many adult tapeworm infectionsa. Preferentially damages tegument of neckb. Praziquanteliv. Neckb. Each segment is a proglottidi. Strobilac. EXAM 1 EXAM 2 Human Parasitology Page 4 Each proglottid develops male and female organsii. Moecious i. Produce sperm which is stored in proglottid1) Male organs form first = protandryii. Female organs develop nextiii. Mature Proglottidsd. Self?fertilizationiv. Cross?fertilizationv. Human Parasitology Page 5 Kevin Human Parasitology
Want to see the other 5 page(s) in Lecture 4.pdf?JOIN TODAY FOR FREE!