Trichuris+enterobius.ppt
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This document provides information on the taxonomy, morphology, life cycles, pathogenesis, clinical features, diagnosis, and treatment of various helminth parasites. It describes the characteristics of nematodes and discusses specific nematodes like Trichuris trichura and Enterobius vermicularis. For T. trichura, it provides details on its morphology, life cycle, clinical manifestations including rectal prolapse, and microscopic identification of eggs in stool samples. For E. vermicularis, it discusses epidemiology in children, morphology of adult worms and eggs, life cycle involving nocturnal emergence of females, and diagnosis using scotch tape tests. Treatment involves repeated doses of albendazole or mebendazole
Trichuris+enterobius.ppt
- 1. B.E Pruitt & Jane J. Stein Trichuris trichura Enterobius vermicularis Dr Kamran Afzal Classified Microbiologist
- 2. Taxonomic Classification of Helminths Sub kingdom Phylum Class Genus – examples Metazoa Nematodes Round worms; appear round in cross section, they have body cavities, a straight alimentary canal and an anus Platyhelminthes Flat worms; dorsoventrally flattened, no body cavity and, if present, the alimentary canal is blind ending Cestodes Adult tapeworms are found in the intestine of their host They have a head (scolex) with sucking organs, a segmented body but no alimentary canal Each body segment is hermaphrodite Taenia (tapeworm) Trematodes Non-segmented, usually leaf- shaped, with two suckers but no distinct head They have an alimentary canal and are usually hermaphrodite and leaf shaped Schistosomes are the exception. They are thread-like, and have separate sexes Fasciolopsis (liver fluke) Schistosoma (not leaf shaped!)
- 3. Taxonomic Classification of Helminths Sub kingdom Phylum Class Genus – examples Metazoa Nematodes Round worms; appear round in cross section, they have body cavities, a straight alimentary canal and an anus Ascaris (roundworm) Trichuris (whipworm) Ancylostoma (hookworm) Necator (hookworm) Enterobius (pinworm or threadworm) Strongyloides Platyhelminthes Flat worms; dorsoventrally flattened, no body cavity and, if present, the alimentary canal is blind ending Cestodes Adult tapeworms are found in the intestine of their host They have a head (scolex) with sucking organs, a segmented body but no alimentary canal Each body segment is hermaphrodite Taenia (tapeworm) Trematodes Non-segmented, usually leaf- shaped, with two suckers but no distinct head They have an alimentary canal and are usually hermaphrodite and leaf shaped Schistosomes are the exception. They are thread-like, and have separate sexes Fasciolopsis (liver fluke) Schistosoma (not leaf shaped!)
- 4. Characteristics of Nematodes Cylindrical and unsegmented Dioecious (male and female) Complete digestive tract (mouth / esophagus / intestine / anus) Adults: sexually reproductive life cycle stage Larvae: developmental or asexually reproductive life cycle stage Eggs: protective stage of zygote &/or embryo Oviparous: production of eggs, discharged from uterus of female Viviparous: production of embryos/L1 larvae, no rigid encapsulation of embryo
- 5. Intestinal Parasites : Mode of infection Ingestion of cysts, oocysts or ova Entry of larvae or oncospheres Site of adult stage or disease Cryptosporidium Giardia Amoebiasis Intestine Toxoplasmosis Visceral larva migrans Trichinella Ingested Disseminated Ascaris Trichuris Enterobius Hookworm Strongyloides through skin Intestine
- 6. Intestinal Parasites : Symptoms Symptoms Parasite Abdominal pain and distension Giardia Cryptosporidium Amoebiasis Ascaris, hookworm, taenia Diarrhoea +/- malabsorption Giardia Cryptosporidium Strongyloides Diarrhoea with blood loss Amoebiasis Trichuris Hookworm Tenesmus, prolapsed rectum Trichuris
- 7. Case History - 1 8-yr-old schoolgirl visiting Pakistan from Malaysia 1 week history of epigastric pain, flatulence, anorexia, bloody diarrhea No eosinophilia noted Clinical diagnosis of amoebic dysentery made
- 8. However, microscopy of stool prep…
- 9. B.E Pruitt & Jane J. Stein Trichuris trichura The ‘Whip-worm’
- 10. 50 mm long with a slender anterior and a thicker posterior end The male is smaller and has a coiled posterior end Morphology - of Adult worms
- 11. Morphology - of Eggs Eggs in stool Size: 50-54 µm by 22-23 µm, Shape is a typical barrel Color is yellow-brown • Unstained two polar plugs Shell quite thick Contains unembryonated egg
- 12. Life cycle
- 13. Life cycle
- 14. Humans sole host Transmission • Fecal-oral via embryonated ova Frequently coexists with ascaris Reservoir • Mainly human, others possible but host specificity not well documented Pathogenic potential • Low to moderate, dependent on worm numbers and location in LI Pathogenesis
- 15. Entirely intraluminal life cycle—eggs are ingested Eggs hatch in intestines, larvae attach, and develop into adults Female lays 3,000-5,000 eggs daily Worms can pierce capillaries, cause localized hemorrhage, and allow bacteria to leave intestine
- 16. Clinical Features Frequently asymptomatic Clinical signs/symptoms - Adult worm (Pathogenic stage) • Dependent on no. of worms; None to digestive disturbances, bloody (frank)/ mucoid diarrhea, abdominal pain and distention, rectal prolapse, anemia and weakness Severe infections • Tenesmus and rectal prolapse in children • Can be fatal in children • Rarely, elephantiasis in adults
- 17. •Trichuris trichiura in the large intestine •Many worms are present, each with its anterior end embedded in the intestinal mucosa, resulting in the erythema
- 18. Lab Diagnosis Stool • Direct examination (Iodine stain) • Eggs • Rarely adult worms Blood • Eosinophilia Histopathology of the intestinal mucosa PCR
- 19. Imaging X-Rays Abdomen • Plain • With contrast / dye CT Scan
- 20. Treatment and Prevention Albendazole 400 mg once Mebendazole 100 mg BD for 3 days (600 mg, repeated after 2 weeks) Pay attention to personal hygiene and eating habits
- 21. Case History - 2 11-year-old female Doing poorly in school Not sleeping well Anorectic Complains of itching in rectal region throughout the day
- 22. A Scotch-tape test reveals…
- 23. B.E Pruitt & Jane J. Stein Enterobius vermicularis The ‘Pin-worm’
- 24. Helminthic Diseases of the Digestive System
- 25. Epidemiology Enterobiasis most common worm disease of children in temperate zones Pre-school and elementary school children affected most often Consmopolitan, 30%~50% of the children population is infested Most common where people live under crowded conditions (orphanages / large families / kindergartens / primary school)
- 26. Morphology of Adult Adult • Female: White 8~13 mm in size Fusiform body with a long, thin, sharply tapering tail Alae (cuticular extension of head) Prominent bulb – Rhabditiform esophagus The greater part of the body is occupied by the uterus filled with eggs • Male: Like female, but about 1/3 to 1/2 size of female The tail is curved, it is rarely seen
- 28. Morphology of Eggs Egg • Oval, clear and colorless • 50 to 60 µm in length, thick shell • Flattened on one side • Contains a larva
- 30. Transmission Definitive host • Human Transmitted by • Ingesting Enterobius eggs
- 31. Pathogenesis Infective stage • Infective eggs Eggs are picked up from surroundings and swallowed • Being sticky, adhere to door handles (especially toilet doors), bedclothes and mug handles etc After hatching in the small intestine, they develop into adults The location of adult • Cecum and colon Anal itching occurs when mature females emerge from intestine to release eggs • Life span of female adult is 1-2 months Right after mating, the male dies • Therefore, the male worms are rarely seen Self-inoculation is common
- 32. Life Cycle
- 33. Life Cycle
- 34. Clinical Features Mostly asymptomatic Nocturnal anal pruritis is cardinal feature due to migration and laying of eggs Perianal pruritus may lead to excoriations and bacterial superinfection Occasionally, invasion of the female genital tract with vulvovaginitis and pelvic or peritoneal granulomas can occur Other symptoms : anorexia, irritability, and abdominal pain May have insomnia, possible emotional symptoms
- 35. Types of infection Infection from environment Auto-infection • Female crawls out of anus and release eggs on the perianal region • Patient feels anal pruritus • Scratching leads to contamination of hands and nails • Re-infection is by hand-mouth transmission Retro-infection • Some eggs hatch on the perianal skin and become larvae • They will crawl back into the anus and mature into adults
- 36. Laboratory Diagnosis Direct fecal smear • Microscopic identification of eggs collected from the perianal area is the method of choice by • Scotch tape technique • Cellophane tape impression • This must be done in the morning, before defecation and washing Alternatively, anal swabs can also be used Brine-floatation method Detection of adult on anal skin at night, when the child is sleeping Larval cultivation
- 37. Treatment Since the life span of the pinworm is less than two months, the major problem is re-infection Repeat the treatment after 2 weeks Repeated re-treatment may be necessary for a radical cure Albendazole is the drug of choice Mebendazole and Pyrantel pamoate are the alternative drugs
- 38. Treat and re-treat the patients and carriers Laundering of bedding Individual health • Observation and correction of personal hygienic and eating habits Public health Health education Prevention