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Nematodes

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Nematodes

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  1. Nematodes Gregory L. Brower, D.V.M., Ph.D. Cell Biology and Anatomy School of Medicine Columbia, South Carolina

  2. Parasitology Resources • World Health Organization • http://www.who.int/en/ • Centers for Disease Control • http://www.cdc.gov/ • http://www.dpd.cdc.gov/dpdx/ • Kansas State University • http://www.k-state.edu/parasitology/ • Atlas of Medical Parasitology • http://www.cdfound.to.it/html/atlas.htm

  3. Parasitology Resources • World Health Organization • Training Manual on Diagnosis of Intestinal Parasites http://www.who.int/wormcontrol/documents/benchaids/training_manual/en/ • United States Military • http://www.phsource.us/PH/TM/index.htm • http://www.phsource.us/PH/PARA/index.htm • Parasitology Autotutorial • http://workforce.cup.edu/buckelew/ • Pubmed and Journal Case Studies

  4. At Risk Populations • Developing Countries • Tropics • Southern United States • Institutional settings (e.g. daycares) • Newly arrived persons • Travelers • Immigrants • Refugees

  5. HelminthicParasites of Man: Round Worms (Nematodes)

  6. Incidence of Parasitism

  7. Number of Specimens Positive For Parasites Year Ascaris Hookworm Trichuris Pinworm 1974-77 3,713 285 1,321 ? 1990-94 572 88 238 ? Incidence of Parasitic Worm Infections in South Carolina

  8. One Worm Means Many Worms

  9. Nematodes: Relative Size

  10. AscarislumbricoidesMorphology

  11. Ascariasis Geographical Distribution

  12. ~200000/day AscarislumbricoidesLife Cycle

  13. Symptoms Organ involved Small and large intestine Abdominal pain; distended abdomen, anorexia, weight loss, occasional vomiting and loose stool Pulmonary Cough wheezing, dyspnea, substernal discomfort Symptoms of Ascariasis

  14. AscariasisExtended Abdomen

  15. AscariasisIntestinal Rupture

  16. 50 :m AscariasisDiagnosis characteristic corticoid eggs in the stool

  17. AscariasisPrevention and Treatment • Good Hygiene • Anthelmintics: • Mebendazole • Albendazole • Ivermectin

  18. Trichinosis Geographical Distribution • World-wide distribution • Not common in Muslim countries • Related To: • Hog Farming Conditions • Pork Consumption

  19. Trichinosis: Incidence in the US

  20. Trichinosis: Case-1 • A 54 year old man who resided in Franklin County. The patient had been hospitalized a 3-week history of diaphoresis, fever, weakness, tachycardia, diarrhea, an 8-pound weight loss, and dry cough. Laboratory testing indicated an elevated white blood cell (WBC) count (20,600/mm3 with 33% eosinophils), hyponatremia), elevated lactate dehydrogenase and elevated creatininephosphokinase. • The patient reported eating 2 pounds of nearly raw bear meat during several meals 2 weeks earlier. Because of suspicion of trichinellosis, albendazole and corticosteroids were administered and the patient recovered fully by February 2004.

  21. Trichinosis: Case-2 • 38 year old man and a woman aged 54 years were admitted to a hospital with 7- and 14-day histories , respectively, of: fever, chills, headache, myalgias, arthralgias, and facial swelling. • The man's WBC count was 14,600/mm3, with 24% eosinophils, 13% lymphocytes, and 2% monocytes. • The woman's WBC count was 16,200/mm3, with 28% eosinophils, 13% lymphocytes, and 3% monocytes. • Serum obtained from both patients tested positive for Trichinella antibodies. • Both were started on a course of albendazole and corticosteroids and recovered fully.

  22. Trichinosis: Case-2 Questioning of the patients revealed that the man had shot a black bear in Canada. The bear was field dressed, and selected meat was packed on ice for transport to Tennessee. The wife prepared and cooked the bear meat on an outdoor grill for themselves and four other persons. The man and woman ate their steaks medium rare; while the other four ate their steaks well done. The meat was examine histologically and numerous Trichinella larvae were observed encysted in characteristic hyalinized capsules in the striated muscle tissue.

  23. TrichinellaspiralisMorphology

  24. TrichinellaspiralisLife Cycle

  25. Trichinosis: Diagnosis • Symptoms • Recent history of eating under-cooked pork, seal or bear • Eosinophilia • Increased serum creatinine phosphate and lactate dehydrogenase • Positive serology

  26. Worm Location Symptoms intestinal mucosa nausea, vomiting, abdominal pain, diarrhea, head ache circulation Edema, periorbital conjunctivitis, photophobia,fever, chill, sweating, muscle pain, spasm, eosinophilia Chest pain, tachycardia, edema, vascular thrombosis myocardium Head ache (supraorbital), vertigo, tinnitus, deafness, mental apathy, delirium, coma, loss of reflexes brain Trichinosis:Symptoms

  27. Trichinella • Muscle invasion stage 2 to 8 weeks after infection. Fever and perorbital edema are followed by myalgia (muscle pain) and weakness. • Characteristic splinter hemorrhages can be found under finger nails (DDX – endocarditis). • Fever and chills can persist for weeks. • Headache is common and dizziness may develop. • Deaths are rare and due to myocarditis, encephalitis and pneumonia (larvae in the diaphragm).

  28. Trichinosis: Treatmentand Prevention Prevention • Elimination of parasite from hogs • Cooking meat well • Freeze pork immediately after packaging Treatment • Corticosteroids for symptomatic relief • Albendazole or Mebendazole for killing parasite

  29. TrichuriasisEpidemiology • A tropical disease, primarily of children • 65% of 1 billion cases seen in Asia and Africa • Seen is rural (low country) South Carolina • Caused by Trichuris trichura (whipworm)

  30. 3000-10000/day TrichuristrichuraLife Cycle

  31. TrichuristrichuraSymptoms • Abdominal pain • Chronic profuse diarrhea with mucus and blood • Weight loss and anemia • Prolapsed rectum

  32. TrichuristrichuraHeavy Infection

  33. 10 :m TrichuristrichuraDiagnosis Symptoms Examine stool for eggs

  34. TrichuristrichuraPrevention and Treatment • Prevention: • Sanitary eating habits • Improved hygiene • Treatment • Mebendazole is effective

  35. PinwormEpidemiology • World-wide, primarily in children • Urban disease in crowded environment • Enterobiusvermicularis

  36. ~10,000/day EnterobiusvermicularisLife Cycle

  37. EnterobiusvermicularisSymptoms • Perianal, perineal and vaginal irritation • Insomnia and restlessness • Occasionally mild abdominal pain, nausea and vomiting

  38. EnterobiusvermicularisPinwormNeurosis Mental distress, guilt complex, and desire to conceal knowledge of the infection from others are perhaps the most significant trauma caused by this persistent, pruritic parasite.

  39. EntrobiusvermicularisDiagnosis Nocturnal observation

  40. EntrobiusvermicularisDiagnosis Scotch tape test for eggs

  41. 50 :m EntrobiusvermicularisDiagnosis Scotch tape test for eggs

  42. EntrobiusvermicularisPrevention and Treatment • Improved hygiene is preventive • Pyrentalpalmoate is very effective • Mebendazole is an alternative

  43. Strongyloides stercoralis Epidemiology • Prevalent in the tropics • Southern US and Puerto Rico

  44. StrongyloidesstercoralisMorphology

  45. StrongyloidesstercoralisLife Cycle

  46. Strongyloides stercoralis Life Cycle

  47. Site Symptoms Pathogenesis Itching and red blotches Cutaneous invasion and sub‑cutaneous migration of larva Skin Verminous pneumonitis Migration of larvae through lung, bronchi, and trachea Pulmonary GI tract Mid-epigastric pain; nausea and vomiting; diarrhea/constipation; bloody dysentery. Attachment of adult worms and injury to upper intestinal mucosa General Weight loss and anemia (rare) Loss of nutrients and blood StrongyloidesstercoralisSymptoms

  48. Strongyloides stercoralis Diagnosis Larvae in stool

  49. StrongyloidesstercoralisPrevention and Treatment • Improved hygiene is preventive • Treatment: • Ivermectin • Albendazole

  50. HookwormEpidemiology