TM29 Helminths 3 Trematodes & Cestodes Past Paper PDF 2023/2024

27 September 2023 TM29 Helminths 3 Trematodes & Cestodes 30 minutes 2023/2024 Dr Stiofán MacGiolla Catháin MB, BCh, BAO, BA, MSc, DFSRH, Prof Cert. Derm Department of International Health and Tropical Medicine Helminths 3: Learning Outcomes Describe the epidemiology, life-cycle, clinical pres...

27 September 2023 TM29 Helminths 3 Trematodes & Cestodes 30 minutes 2023/2024 Dr Stiofán MacGiolla Catháin MB, BCh, BAO, BA, MSc, DFSRH, Prof Cert. Derm Department of International Health and Tropical Medicine Helminths 3: Learning Outcomes Describe the epidemiology, life-cycle, clinical presentation, management, diagnosis, prevention and natural history of schistosomiasis Describe the life-cycle of Taenia and Echinococcus with reference to diagnosis, treatment and prevention  Nematodes Plathyhelminths ‘Roundworms’ ‘Flatworms’ Filariae Trematodes Cestodes ‘Flukes’ ‘Tapeworms’ Soil- transmitted Helminths Lymphatic Onchocerca Loa loa Filariasis Schistosoma Taenia Echinococcus ‘Hydatid Disease’ Hookworm Ascaris Trichuris Strongyloides ‘Roundworm’ ‘Whipworm’ ‘Threadworm’  Platyhelminths ‘Flatworms’ Trematodes Cestodes ‘Flukes’ ‘Tapeworms’ Schistosoma Taenia Echinococcus ‘Hydatid Disease’ Trematodes (Flukes) Trematode Features Platyhelminths Flat & tongue-like ‘Flatworms’ Oral & ventral suckers Trematodes Cestodes ‘Flukes’ Incomplete digestive system - no anus Schistosoma Taenia Echinococcus ‘Creeping’ motion Hermaphroditic except for Schistosoma  Helminths Trematodes (Flukes) Platyhelminths ‘Flatworms’ From German ‘flach’ – meaning flat Trematodes ‘Flukes’ Lung flukes Schistosoma Paragonimus ‘Blood Flukes’ Liver flukes Fasciola hepatica Fasciola gigantica Oriental liver flukes Opistorchis Gut flukes Clonorchis Fasciolopsis buski Blood flukes Schistosoma  Helminths Global Burden of Schistosomiasis Platyhelminths ‘Flatworms’ Trematodes ‘Flukes’ Schistosoma ‘Blood Flukes’ *DALY = Disability-Adjusted Life Year; i.e. years of healthy life lost – combines morbidity and mortality into single metric  Helminths Schistosomiasis Schistosoma haematobium, S. mansoni, S. japonicum Platyhelminths ‘Flatworms’ Urogenital Hepatic/ Trematodes ‘Flukes’ Intestinal Schistosoma ‘Blood Flukes’ Oncomelania snail1 Biomphalaria snail1 Bulinus snail1 Tropics & subtropics Poor communities Poor drinking water & sanitation Mostly children ~90% in Sub-Saharan Africa 1Fred A. Lewis, Yung-san Liang, Nithya Raghavan & Matty Knight - The NIH-NIAID Schistosomiasis Resource Center. PLoS Neglected Tropical Diseases 2(7): e267. doi:10.1371/journal.pntd.0000267  Helminths Schistosomiasis Life-cycle Platyhelminths ‘Flatworms’ Trematodes ‘Flukes’ Schistosoma in venous plexus Schistosoma ‘Blood Flukes’ 50% eggs stuck penetrate the tissue ↓ fibrosis & granulomatous reactions. Figure: CDC - Schistosomiasis- Biology [Internet]. Cdc.gov. 2021. Available from: https://www.cdc.gov/parasites/schistosomiasis/biology.html  Helminths Schistosomiasis Clinical Presentation: General Platyhelminths ‘Flatworms’ Acute Chronic Trematodes ‘Flukes’ Fever Fibrosis & Schistosoma Flu-like illness granulomatous reaction ‘Blood Flukes’ Coincides with Cough/wheeze/SOB onset of EGG Stunted growth production Diarrhoea 3-8 weeks Impaired cognitive development Eosinophilia post infection Anaemia Urticaria Symptoms not caused by the worms themselves but by the immune Dermatitis (at site of penetration) response to the eggs  Helminths Schistosomiasis Clinical Presentation: Specific Platyhelminths ‘Flatworms’ Cystitis Bloody diarrhoea Trematodes ‘Flukes’ Haematuria Intestinal polyps Obstructive uropathy Hepatomegaly Hepatic-Intestinal Schistosoma Urogenital ‘Blood Flukes’ CKD Cirrhosis/CLD: portal HTN Infertility splenomegaly varices Bladder CA Female Genital Schistosomiasis Ectopic egg migration → CNS, lungs etc.  Helminths Schistosomiasis Diagnosis Platyhelminths ‘Flatworms’ Clinical presentation Antibodies Trematodes ‘Flukes’ Irrelevant in endemic areas → high exposure e.g. haematuria May be helpful in earlier infection Schistosoma Eosinophilia suggestive ‘Blood Flukes’ Urine/stool microscopy: to detect eggs (midday = peak shedding) Antigen test Schistosoma haematobium egg in wet mount of urine1 Active infection Clear 24-48 hrs after successful treatment 1. CDC - Schistosomiasis- Biology [Internet]. Cdc.gov. 2021. Available from: https://www.cdc.gov/parasites/schistosomiasis/biology.html  Helminths Schistosomiasis Management Platyhelminths ‘Flatworms’ PRAZIQUANTEL x2 doses Trematodes ‘Flukes’ 60-90% cure rate safe (incl in pregnancy) + cheap Schistosoma ‘Blood Flukes’ Only active against adult worms ↓ Need to wait 12 weeks from suspected time of infection to allow juvenile worms to develop into adults  Helminths Schistosomiasis Prevention & Control Platyhelminths ‘Flatworms’ WaSH education Trematodes ‘Flukes’ Safe clothes-washing → buckets Toilet facilities beside lakes Schistosoma ‘Blood Flukes’ Clean water access Clear snail breeding habitats Chemicals to kill snails in water → Biological killing – fish that eat snail eggs Mass Drug Administration Praziquantel With other MDA programmes e.g. STH  Helminths Schistosomiasis Points to remember Platyhelminths ‘Flatworms’ 1. Highest global burden of all helminths – disease of poverty Trematodes 2. Intermediate host = aquatic snails ‘Flukes’ 3. 2 main disease presentations – hepatic/intestinal & urogenital Schistosoma ‘Blood Flukes’ 4. Symptoms not from worms themselves but immune response to eggs 5. Diagnosis: microscopy of urine/stool to detect eggs 6. Management: PRAZIQUANTEL 7. Prevention & Control: W.A.S.H., health education, snail control 8. Mass Drug Administration – alongside other control programmes Cestodes (Tapeworms) Platyhelminths ‘Flatworms’ Cestode Features Ribbon-like Trematodes Cestodes segmented bodies ‘Flukes’ ‘Tapeworms’ No digestive system – nutrients absorbed through Schistosoma Taenia Echinococcus ‘Hydatid body wall Disease’ Hermaphroditic  Helminths Global Burden of Cestode Infections Platyhelminths ‘Flatworms’ Disease DALYs* Cestodes Schistosomiasis 2,543,000 ‘Tapeworms’ Cysticercosis 1,912,000 Hookworm 1,682,000 Taenia Ascariasis 1,433,000 Lymphatic filariasis 1,186,000 Food-borne trematodiases 1,084,000 Onchocerciasis 962,000 Echinococcosis 687,000 Trichuriasis 337,000 TOTAL 2,599,000 Taenia solium  Helminths Cysticercosis Taenia solium Platyhelminths ‘Flatworms’ The same tapeworm Cestodes ‘Tapeworms’ (Taenia solium) causes 2 different infections depending on stage of lifecycle Taenia ingested… Geographic distribution of Taenia solium Taeniasis/Cystercosis1 1. CYSTICERCOSIS = ingestion of T. solium EGGS 2. TAENIASIS (Intestinal Tapeworm) = ingestion of T. solium ADULT TAPEWORM Taenia solium → pork tapeworm Ingesting undercooked Taenia saginata → beef tapeworm meat from infected animals 1. Garcia H, Gonzalez A, Gilman R. Taenia solium Cysticercosis and Its Impact in Neurological Disease. Clinical Microbiology Reviews. 2020;33(3).  Helminths Cysticercosis Life-cycle Platyhelminths ‘Flatworms’ PIGS = usual intermediate Cestodes hosts for T. solium ‘Tapeworms’ CYSTICERCOSIS Humans can become Taenia intermediate hosts if they accidentally ingest infective eggs from the faeces of a human tapeworm carrier → CYSTICERCOSIS TAENIASIS (Intestinal Tapeworm) Dormant cysts may form in any tissue (most commonly brain, eyes, subcutaneous tissues) Figure: CDC - Cysticercosis- Biology [Internet]. Cdc.gov. 2021. Available from: https://www.cdc.gov/parasites/cysticercosis/biology.html  Helminths Cysticercosis NEUROCYSTICERCOSIS Reason for high Clinical Presentation morbidity and mortality Platyhelminths ‘Flatworms’ related to CYSTICERCOSIS 1. CYSTICERCOSIS Cestodes ‘Tapeworms’ Brain (NEUROCYSTICERCOSIS) - Asymptomatic → Headaches Eyes SEIZURES!!! Taenia Hydrocephalus Subcutaneous tissues Disseminated Cysticercosis in subcutaneous tissues and muscles3 Ocular Cysticercosis2 Neurocystercosis1 2. TAENIASIS (Intestinal Tapeworm) → few problematic symptoms 1. Dhesi B, Karia SJ, Adab N, et al Imaging in Neurocysticercosis Practical Neurology 2015;15:135-137 2. Thatte et al. (2014). Clinical study of histologically proven conjunctival cysts. Saudi Journal of Ophthalmology. 29. 10.1016/j.sjopt.2014.06.009. 3. Rajesh Jawale, Dhananjay Duberkar Neurology Jan 2015, 84 (3) 327; DOI: 10.1212/WNL.0000000000001152  Helminths Neurocysticercosis Cysticercosis of the Brain/CNS Platyhelminths ‘Flatworms’ Most frequent preventable cause of epilepsy worldwide Cestodes ‘Tapeworms’ ~30-70% of all epilepsy cases in endemic countries Taenia Affects subsistence farming communities (in developing countries of Africa, Asia and Latin America) Epilepsy can cause major stigma, especially in girls and women (commonly associated with witchcraft in affected rural communities) ↓ market value of pigs, makes pork unsafe to eat  Helminths Cysticercosis/Taeniasis Diagnosis Platyhelminths ‘Flatworms’ 1. CYSTICERCOSIS – investigation depends on suspected tissue involved Cestodes ‘Tapeworms’ Brain/CNS: (NEUROCYSTICERCOSIS) – CSF, CT/MRI Brain Muscle: biopsy, radiological imaging e.g. MRI Taenia Eye: ophth exam, radiological imaging e.g. US Serology What is a PROGLOTTID? 2. TAENIASIS (Intestinal Tapeworm) Faecal microscopy: detect PROGLOTTIDS Eggs distinguish between species – rarely detected Taenia egg Video of proglottid formation1 Taenia solium proglottid The Flea Tapeworm in dogs and cats [Internet]. Youtube.com. 2021. Available from: https://www.youtube.com/watch?v=CzdhZQiRmic  Helminths Cysticercosis/Taeniasis Management Platyhelminths ‘Flatworms’ 1. CYSTICERCOSIS Cestodes ‘Tapeworms’ ACTIVE NEUROCYSTICERCOSIS: Cyst destruction → inflammatory response Taenia PRAZIQUANTEL + ALBENDAZOLE + STEROIDS +/- ANTI EPILEPTIC DRUGS INACTIVE NEUROCYSTICERCOSIS → No treatment required 2. TAENIASIS (Intestinal Tapeworm) PRAZIQUANTEL single dose  Helminths Cysticercosis/Taeniasis Goal of control is to prevent eggs from entering Prevention & Control the environment Platyhelminths ‘Flatworms’ Health education – hygiene, food safety Cestodes ‘Tapeworms’ Improved sanitation & toilet facilities Taenia Test & treat human Taenia carriers Improved pig husbandry (no free-roaming) Vaccination & treatment of pigs Improved meat inspection and processing of meat products Cook meat thoroughly Taenia solium cysts in pork1 1. Garcia H, Del Brutto O. Neurocysticercosis: updated concepts about an old disease. The Lancet Neurology. 2005;4(10):653-661. Echinococcus granulosis  Helminths Echinococcosis Echinococcus granulosus, Echinococcus multilocularis Platyhelminths ‘Flatworms’ Cystic Echinococcosis Echinococcus granulosus = dog tapeworm → (Hydatid Disease) Cestodes (Echinococcus multilocularis = fox tapeworm → Alveolar Echinococcosis) ‘Tapeworms’ Echinococcus Cystic Echinococcosis Accounts for most of global Echinococcosis burden but only 2-4% mortality Alveolar Echinococcosis Harder to treat, worse outcomes Very high mortality Map: Echinococcosis: Advances in the 21st Century. Hao Wen, Lucine Vuitton, Tuerhongjiang Tuxun, Jun Li, Dominique A. Vuitton, Wenbao Zhang, Donald P.McManus. Clinical Microbiology Reviews Feb 2019  Helminths Cystic Echinococcosis (Hydatid Disease) Life-cycle Platyhelminths ‘Flatworms’ Eggs ingested by sheep Cestodes ‘Tapeworms’ Penetrate wall of intestine Form cysts in sheep tissues Echinococcus Sheep ingested by dog Cysts develop into adult worm in dog’s intestine & produce proglottids Eggs shed in dog faeces Humans infected when they accidentally ingest eggs Figure: CDC – Cystic Echinococcus- Biology [Internet]. Cdc.gov. 2021. Available from: https://www.cdc.gov/parasites/cysticechinococcus/biology.html  Helminths Cystic Echinococcosis (Hydatid Disease) Clinical Presentation Platyhelminths ‘Flatworms’ Symptoms due to pressure from cysts Cestodes ‘Tapeworms’ Liver (70%) – obstruction → jaundice, RUQ pain, liver failure Lungs (15-30%) – dyspnoea, cough, chest pain Echinococcus May be asymptomatic until large enough to cause symptoms Dangerous if cysts rupture Hydatid cyst in lung1 1. Case of Dr Mohammad Taghi Niknejad, rID: 62478  Helminths Cystic Echinococcosis (Hydatid Disease) Diagnosis Management Platyhelminths ‘Flatworms’ 1. Imaging: 1. ALBENDAZOLE Cestodes ‘Tapeworms’ Ultrasound 2. PAIR procedure: CT 1. Percutaneous Aspiration Echinococcus MRI 2. Injection [with scolicide] May see DAUGHTER CYSTS 3. Re-aspiration 2. Serology to confirm 3. Surgery Cysts in locations at risk of pressure effects/rupture https://www.youtube.com/watch?v=YtIWfxqf0mo  Helminths Cystic Echinococcosis (Hydatid Disease) Prevention & Control Platyhelminths ‘Flatworms’ Health education Cestodes Cook food well ‘Tapeworms’ Strict control of livestock slaughter Echinococcus Prevent dogs feeding on sheep carcasses Treating dogs in endemic areas Control dog population  Nematodes Plathyhelminths ‘Roundworms’ ‘Flatworms’ Filariae Trematodes Cestodes ‘Flukes’ ‘Tapeworms’ Soil- transmitted Helminths Lymphatic Onchocerca Loa loa Filariasis Schistosoma Taenia Echinococcus ‘Hydatid Disease’ Hookworm Ascaris Trichuris Strongyloides ‘Roundworm’ ‘Whipworm’ ‘Threadworm’ Reading Resources Nick Beeching, Geoff Gill, Dom Colbert, (2004), Lecture Notes in Tropical Medicine, Edition: 7th, Wiley Blackwell Centre for Disease Control DPDx Parasites A-Z Index: https://www.cdc.gov/dpdx/az.html  27 September 2023 TM30 Amoeda & Giardia 30 minutes 2023/2024 Dr Stiofán MacGiolla Catháin MB, BCh, BAO, BA, MSc, DFSRH, Prof. Cert. Clin. Derm. Department of International Health and Tropical Medicine  Objectives ▪ Describe the life cycle of Entamoeba histolytica and Giardia lamblia with reference to diagnosis, treatment and prevention Entamoeba histolytica Amoebiasis epidemiology ▪ Intestinal protozoan parasite ▪ Invades and lysis cells ▪ Risk factors ▪ Areas of poor hygiene and sanitation ▪ Living in residential institutions ▪ MSM ▪ Immunosuppressed ▪ ~20% symptomatic ▪ 40 to 50m cases of symptomatic/year ▪ Mortality 40,000- 100,000 Parasite and life-cycle ▪ Caused by Entamoeba Histolytica ▪ primarily a disease of humans ▪ Cyst ingested ▪ Digested in the gut ▪ Cysts pass in stool ▪ Cysts killed by drying >50* or cooling F ▪ Most common age 20-40 yo ▪