Cdc health and parasitology


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CDC Health Parasites

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Cdc health and parasitology

  2. 2. PHYLUM NEMATODA • Nematodes or true roundworms • Unsegmented, elongated and cylindrical in shape • Sexes are separate and the females are larger than males • Life cycle includes: 1) the egg stage 2) four larval stage and 3) the adult stage
  3. 3. CLASS APHASMIDIA A. Species which parasitize the small intestines 1. Trichinella spiralis 2. Capillaria philippinensis B. Species which parasitize the large intestines 1. Trichuris trichiura
  4. 4. CLASS PHASMIDIA A. Species which parasitize the small intestines 1. Ascaris lumbricoides 2. Necator americanus 3. Ancylostoma duodenale 4. Ancylostoma ceylanicum 5. Strongyloides stercoralis
  5. 5. CLASS PHASMIDIA B. Species which parasitize the large intestines 1. Enterobius vermicularis C. Species which parasitize the tissues 1. Wuchereria bancrofti 2. Brugia malayi
  6. 6. CLASS PHASMIDIA D. Species which cause larva migrans in man 1. Ancylostoma braziliense 2. Ancylostoma caninum 3. Angiostrongylus cantonensis
  7. 7. Ascaris lumbricoides Common Name: Giant Intestinal Roundworm Final Host: Man Habitat: Small Intestine Diagnostic Stage: Ova (fertilized or unferilized) Infective Stage: Embryonated Ova Sources of Infection: Soil Transmitted Helminthes Mode of transmission: Ingestion Portal of Entry: Mouth
  8. 8. Ascaris lumbricoides Morphology: The adult worms are creamy-white to pinkish yellow when freshly expelled. The head is provided with 3 lips and a small triangular buccal cavity Female: female worm is tapered at both ends and large (20 to 35 cm long, up to 45cm) Male: smaller and slender, curve posteriorly and equip with copulatory spicule
  9. 9. 1. Cuticle and hypodermis 2. Longitudinal muscle layer 3. Vas deferens 4. Testis 5. Lateral line with excretory canal 6. Intestine 7. Pseudocoelom Ascaris lumbricoides – male (cross section)
  10. 10. 1. Cuticle and hypodermis 2. Longitudinal muscle layer 3. Ovary 4. Oviduct 5. Uterus 6. Intestine Ascaris lumbricoides – female (cross section)
  11. 11. The three lips are seen at the anterior end. The margin of each lip is lined with minute teeth which are not visible at this magnification. Ascaris lumbricoides - lips
  12. 12. A fertilized corticated Ascaris egg, still at the unicellular stage, as they are passed in stool. All membranes are present. The outer *mamillary coat, the middle gycogen and the innermost vitelline layer. * Lacking in decorticated ova. Ascaris lumbricoides - egg
  13. 13. The chitinous layer and albuminous coat are thinner than those of the fertilized eggs without ascaroside and fertilizing membrane. The content is made of many refractile granules various in size. Ascaris lumbricoides - egg
  14. 14. Ascaris lumbricoides – life cycle
  15. 15. Adult worms live in the lumen of the small intestine. A female may produce up to 240,000 eggs per day, which are passed with the feces Fertile eggs embryonate and become infective after 18 days to several weeks , depending on the environmental conditions (optimum: moist, warm, shaded soil). After infective eggs are swallowed , the larvae hatch , invade the intestinal mucosa, and are carried via the portal, then systemic circulation to the lungs . The larvae mature further in the lungs (10-14 days), penetrate the alveolar walls, ascend the bronchial tree to the throat, and are swallowed . Upon reaching the small intestine, they develop into adult worms . Between 2 and 3 months are required from ingestion of the infective eggs to oviposition by the adult female. Adult worms can live 1 to 2 years Ascaris lumbricoides – life cycle
  16. 16. Pathology: Larva: - Ascaris pneumonitis/ Loeffler’s syndrome - difficulty in breathing, coughing, fever, lung infiltration - larva may become ERATIC Adult: - diarrhea - malnutrition - villi atrophy - worm bolus/obstruction Treatment: Mass treatment or Selective Treatment Drug of choice: Mebendazole or Pyrantel pamoate Ascaris lumbricoides
  17. 17. Ascaris lumbricoides Diagnosis: 1. Direct Fecal Exam 2. Kato (qualitative) and Kato-katz technique (quantitative) 3. Stool exam 4. Concentration Techniques (Floatation, Sedimentation) Prevention and Control
  18. 18. Trichuris trichiuria Common Name: Whipworm Final Host: Man Habitat: Large Intestine - attached Diagnostic Stage: Ova Infective Stage: Embryonated Ova Sources of Infection: Soil Transmitted Helminthes Mode of transmission: Ingestion Portal of Entry: Mouth
  19. 19. ADULT MORPHOLOGY  Flesh colored or pinkish slender worm Anterior 2/3 of the worm is attenuated and thin in contrast to the remaining posterior 1/3 which is fleshy and robust “Whip like appearance”
  20. 20. FEMALE MALE Trichuris trichiuria
  21. 21. Trichuris trichiuria - ova -With mucoid, bipolar plug -Foot ball - shaped -Lemon-shaped -Barrel-shaped * Diagnostic stage
  22. 22. Trichuris trichiuria – life cycle
  23. 23. The unembryonated eggs are passed with the stool . In the soil, the eggs develop into a 2-cell stage , an advanced cleavage stage , and then they embryonate ; eggs become infective in 15 to 30 days. After ingestion (soil-contaminated hands or food), the eggs hatch in the small intestine, and release larvae that mature and establish themselves as adults in the colon . The adult worms (approximately 4 cm in length) live in the cecum and ascending colon. The adult worms are fixed in that location, with the anterior portions threaded into the mucosa. The females begin to oviposit 60 to 70 days after infection. Female worms in the cecum shed between 3,000 and 20,000 eggs per day. The life span of the adults is about 1 year. Trichuris trichiuria – life cycle
  24. 24. Trichuris trichiuria Diagnosis: * same with Ascaris lumbricoides Pathology: - diarrhea - Iron Deficiency Anemia - rectal prolapse To declare free from A. lumbricoides and T. trichiuria - three specimens are negative - stool negative for egg - all male parasite - female worms are still immature (migration stage) - unfetilized egg (all females or males are still immature) Drug of choice: Mebendazole
  25. 25. The Hookworms 1. Necator americanus 2. Ancylostoma duodenale 3. Ancyiostoma braziliense 4. Ancylostoma caninum
  26. 26. Ancylostoma duodenale Necator americanus Common name: Old world Hookworm New world Hookworm Body Curvature: “C” shaped “S” shaped Dental pattern: 2 pairs of teeth Semi lunar cutting plate Bursa: Dorsal ray, tridigitate or tripartite Dorsal ray bidigitate or bifid Spicule: Plain, bristle-like Barbed, fused Habitat: Small intestine Small intestine Diagnostic stage: Ova Ova Infective stage: L3 (filariform) L3 (filariform) MOT Skin penetration, transmammary Purely percutaneous
  27. 27. Ancylostoma duodenale Necator americanus two pairs of teeth Semi lunar cutting plate Dorsal ray, tridigitate or tripartite Dorsal ray, bifid
  28. 28. The Hookworms – life cycle
  29. 29. The Hookworms – life cycle Eggs are passed in the stool , and under favorable conditions (moisture, warmth, shade), larvae hatch in 1 to 2 days. The released rhabditiform larvae grow in the feces and/or the soil , and after 5 to 10 days (and two molts) they become become filariform (third-stage) larvae that are infective These infective larvae can survive 3 to 4 weeks in favorable environmental conditions. On contact with the human host, the larvae penetrate the skin and are carried through the veins to the heart and then to the lungs. They penetrate into the pulmonary alveoli, ascend the bronchial tree to the pharynx, and are swallowed . The larvae reach the small intestine, where they reside and mature into adults. Adult worms live in the lumen of the small intestine, where they attach to the intestinal wall with resultant blood loss by the host
  30. 30. The Hookworms Ova: Thin-shelled 2-4-8 cell stages (blastomeres) *No species identification Pathology: anemia pneumonitis (Wakana Disease) creeping eruption – cutaneous larva migrans (CML) Lab test: Stool Exam Harada Mori Technique Rx of choice: Albendazole Mebendazole
  31. 31. COMPARATIVE STUDY ON HOOKWORM AND STRONGYLOIDES STERCORALIS LARVA  Hookworm L1 Strongyloides long = buccal capsule= short small = genital primordium= prominent L3 shorter = esophagus = longer pointed = tail end = notched both sheathed
  32. 32. Strongyloides stercoralis Common Name: Threadworm, smallest nematode of man Final Host: Man Habitat: Small Intestine Diagnostic Stage: Rhabditiform Larva Infective Stage: Filariform Larva *causative agent of Cochin China Diarrhea Pathology: Diarrhea Honey Comb Ulcer Lab Test: Stool Exam Duodenal Aspirate Entero Test
  33. 33. Strongyloides stercoralis
  34. 34. Strongyloides stercoralis rhabditiform larva of Strongyloides stercoralis. The rhabditiform larva are usually mistaken from that of the hookworms rhabditiform.
  35. 35. egg capsule of Strongyloides stercoralis from free-living female. The larvae is well formed with transparent capsule. Strongyloides stercoralis
  36. 36. Capillaria philippinensis Common Name: Pudoc worm Final Host: Man/ other vertebrae Intermediate host: glass fish Habitat: Small Intestine Diagnostic Stage: Ova in stool Infective Stage: Larva in IH Sources of Infection: Food borne Mode of transmission: Ingestion Portal of Entry: Mouth
  37. 37. Capillaria philippinensis
  38. 38. Capillaria philippinensis – life cycle (1) Unembryonated eggs deposited in the intestinal lumen of either the avian or human host are expelled in the feces, whereupon the eggs are released into the external (usually aqueous) environment. (2) The unembryonated eggs become embryonated while in the fresh- or brackish- water. (3) The embryonated eggs are ingested by fresh- or brackish-water fish. which serve as the intermediate host for the Capillaria philippinensis. Inside the intestinal lumen of the fish, the larvae hatch, burrow through the intestinal mucosa, and permeate the fish's mesenteric and peripheral tissues. (4) The parasite enters the intestinal lumen of humans, fish-eating birds, and other animal hosts upon ingestion of raw or undercooked C. philippinensis infected fish. (5) The adult worms of Capillaria philippinensis burrow into the intestinal mucosa (most typically of the jejunum). (6)While in the intestinal lumen of the human or avian host, the female worms deposit unembryonated eggs, which are subsequently expelled in the host's feces. (Albeit a rare occurence, the eggs of Capillaria philippinensis may become embryonated within the intestine of the human host. The subsequent release of infective larvae leads autoinfection and hyperinfection.
  39. 39. Capillaria philippinensis Morphology: Female: 2.5-4.4mm 1. Typical Female –egg in uterus (8-10) in single row 2. Atypical Female – viviparous, larvivapous, 40-45 eggs arranged in 2-3 rows Male: 2.2-3.2mm - with chitinized spicule and a long spicule sheath Female Male
  40. 40. Capillaria philippinensis Morphology: Ova: Produced by typical female -moderately thick striated egg sheath -with flattened bipolar plugs - 1-2 segmentation *Diagnostic stage
  41. 41. Capillaria philippinensis -Can cause microulceration, depression of intestinal villi -Borborygmi -Abdominal pain -Diarrhea -Weight loss -Malabsorption -Low plasma electrolyte concentration Pathology: Laboratory test: - DFS - Concentration techniques (FECT) - examination of duodenal aspirate Rx of choice: Albendazole, Mebendazole
  42. 42. Enterobius vermicularis Common Name: Pinworm, seatworm, society worm Final Host: Man Habitat: Large Intestine Diagnostic Stage: Ova Infective Stage: embryonated ova Sources of Infection: Contact borne Mode of transmission: Ingestion, inhalation
  43. 43. Enterobius vermicularis
  44. 44. Enterobius vermicularis Eggs are deposited at night by the gravid females. Eggs are ingested via person-to-person transmission through the handling of contaminated surfaces (such as clothing, linen, curtains, and carpeting), or airbourne eggs may be inhaled and swallowed. Self-infection may also occur if eggs are transferred from to the mouth by fingers that have scratched the perianal area. After ingestion, larvae hatch from the eggs in the small intestine. The adults then migrate to the colon. The life span of the adults is about two months. Adults mate in the colon, and the males die after mating. Gravid females migrate nocturnally to the anus and ovideposit eggs in the perianal area. The females die after laying their eggs. The time period from ingestion of infective eggs to the ovideposition of eggs by females is approximately one month. The larvae develop and the eggs become infection within 4-6 hours. Newly hatched larvae may also migrate back into the anus, and this is known as retroinfection.
  45. 45. Enterobius vermicularis - morphology Adult Female: E. vermicularis have a long, pointed tail (arrow) leading to the common name of pinworm. They are about 8-13 mm in length. Adult Male: The adult male is about 2-5 mm in length and has a curved, relatively blunt posterior end (arrow).
  46. 46. Enterobius vermicularis - morphology Adult Male: This image shows a closeup of the male. Note the esophageal bulb, characteristic of the species, in the anterior end (black arrow) and the curled posterior tail with a spicule, characteristic of the male (red arrow). Egg: The egg of E. vermicularis is approximately 25 x 60 um in size. It has a thin shell and one of the sides is flattened. Eggs are collected by swabbing the perianal area during the early morning with an adhesive tape and then examining the tape with a microscope.
  47. 47. Enterobius vermicularis Pathology: - Itchiness - Secondary bacterial infection - Nocturnal pruritus ani Lab diagnosis: -Scoth tape swab -Swellengrebel -Petrolatum Coated Swab Rx of choice: Mebendazole
  48. 48. Angiostrongylus cantonensis Common Name: Rat lung worm Final Host: Rattus norvegicus Rattus rattus rattus Intermediate Host: Achanita fulica
  49. 49. Angiostrongylus cantonensis FEMALE MALE -Intestine fille with blood -Interwinding uterus -‘barber’s pole” - Bean shaped bursa
  50. 50. Angiostrongylus cantonensis
  51. 51. PATHOLOGY Angiostrongylosis - Eosinophilic meningoencephalitis - Increasing confusion, incoherence, impaired memory - Marked tissue necrosis
  52. 52. DIAGNOSIS CSF examination with moderate to high white blood cell count - Pleocytosis Patient history of eating any possible intermediate host is important Large numbers of Charcot-Leyden crystals are present in the meninges
  53. 53. FILARIAL WORMS Family Filariidae Slender filarial worms Arthropod-transmitted parasite of the circulatory and lymphatic system Medically important species in the Philippines are Wuchereria bancrofti and Brugia malayi
  54. 54. Wucheria bancrofti Brugia malayi Common name Brancroft’s Filarial Worm Malayan Filarial Worm Final Host Anopheles, Aedes, Culex Mansonia bonneae , M. uniformis Host – adult Lower lymphatic Upper lymphatic Diagnostic Stage Microfilaria Microfilaria Infective Stage L3 filariform L3 filariform Mode of Transmission Skin penetration Skin penetration Periodicity Nocturnal Periodic-nocturnal subperiodic
  55. 55. Wucheria bancrofti Brugia malayi Cephalic space 1:1 2:1 Sheath affinity to Giemsa Unstained Stained- pink Body nuclei Regularly shaped Overlapping/ irregular Terminal nuclei None Two nuclei Appearance Graceful curve Kinky/ stiff Pathology Bancroftian Filariasis Malayan Filariasis
  56. 56. Wucheria bancrofti Brugia malayi Microfilaria
  57. 57. Microfilariae – life cycle
  58. 58. DIAGNOSIS 1. Blood smear examination Sample obtained between 10:00 PM – 2:00 AM 2. Knott’s concentration technique (2ml blood:10ml of 2% formalin) 3. RDT- ICT- antigen detection (CFA)
  59. 59. TREATMENT, PREVENTION AND CONTROL 1. Single dose - Diethylcarbamazine(DEC) - Ivermectin 2. DEC-medicated table salt
  60. 60. TREATMENT, PREVENTION AND CONTROL Educate communities about : - The value of intensive local hygiene - Awareness on etiology, prevention and control of filariasis Personal protective measures may help prevent contact with mosquito vectors