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Enteric Nematodes Ascaris lumbricoides Enterobius vermicularis

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Presentation on theme: "Enteric Nematodes Ascaris lumbricoides Enterobius vermicularis"— Presentation transcript:

1 Enteric Nematodes Ascaris lumbricoides Enterobius vermicularis
Trichuris trichiura Hookworms Ancylostoma duodenale Necator americanus Strongyloides stercoralis

2 What you should know about the Enteric Nematodes
Name of organism and disease Transmission (how acquired?) Location and migration in human Major clinical manifestations including presence/absence of eosinophilia Diagnostic tests

3 Organism: Ascaris lumbricoides Disease: Ascariasis
Geographical Distribution: Worldwide 1.2 billion infected (20%); 20,000 deaths Transmission: Ingestion of Ova Fecal contamination of water, soil and hands

4 Ascaris lumbricoides Location of Parasite Larvae hatch in GI tract,
penetrate GI wall, migrate via lungs & bronchi back to GI (Adult stage)

5 Ascaris lumbricoides Morphology: Adult, cm Female Male

6 Ascaris lumbricoides Morphology: Ova Unfertilized Fertilized
Embryonated Infective

7 Ascaris lumbricoides Clinical:
Larval migration in lungs usually asymptomatic, but may be transient eosinophilia Intestinal stage may produce abdominal pain, diarrhea & non-specific gastrointestinal complaints Intestinal obstruction

8 Ascaris lumbricoides Clinical:

9 Ascaris lumbricoides Clinical:

10 Ascaris lumbricoides Clinical:

11 Ascaris lumbricoides Clinical:


13 Ascaris lumbricoides Diagnosis: O&P Test Control & Treatment:
Mebendazole, albendazole

14 Ascaris lumbricoides

15 Organism: Enterobius vermicularis PINWORM Disease: Enterobiasis
Geographical Distribution: Worldwide, 20-60% school age children Transmission: Ingestion (and inhalation) of eggs Location of Parasite: Adults in proximal intestine, cecum & appendix nocturnal deposition of eggs on perianal area

16 Enterobius vermicularis
Morphology: Adults are 1 cm Clinical: Asymptomatic, vaginal pruritis No migration, No eosinophilia Reinfection common

17 Enterobius vermicularis

18 Enterobius vermicularis

19 Enterobius vermicularis

20 Enterobius vermicularis

21 Enterobius vermicularis

22 Enterobius vermicularis

23 Enterobius vermicularis
Diagnosis: “Scotch” Tape test for eggs Control & Treatment: Mebendazole

24 Enterobius vermicularis

25 Organism: Trichuris trichiura WHIPWORM Disease: Trichuriasis
Geographical Distribution: Worldwide Transmission: Ingestion of eggs Location of Parasite: Adult embedded in mucosa of cecum, colon, & rectum

26 Trichuris trichuria Morphology: Adult 3-5 cm
Anterior (digestive) end is thin Posterior (reproductive) end is thick

27 Trichuris trichuria

28 Trichuris trichuria

29 Trichuris trichuria Clinical: Light infections - asymptomatic
Heavy infections - diarrhea bloody diarrhea, rectal prolapse Diagnosis: O&P Test Control & Treatment: Mebendazole & Albendazole

30 Trichuris trichuria

31 Trichuris trichuria

32 Trichuris trichuria

33 Organism: Ancylostoma duodenale & Necator americanus HOOKWORMS
Disease: Hookworm anemia Geographical Distribution: Humid areas with poor sanitation Transmission: Direct penetration of unbroken skin by larva

34 Ancylostoma duodenale & Necator americanus
Location of Parasite: Adults attached to mucosa of duodenum and proximal small intestine Morphology: Adults are 1 cm

35 Ancylostoma duodenale
& Necator americanus

36 Ancylostoma duodenale
& Necator americanus

37 Ancylostoma duodenale

38 Necator americanus

39 Ancylostoma duodenale
& Necator americanus

40 Ancylostoma duodenale & Necator americanus
Clinical: Red pruritic lesions at site of larval penetration Eosinophilia possible Asymptomatic Gastric pain & diarrhea Anemia (due to blood loss) Diagnosis: O&P Test Control & Treatment: Mebendazole & Albendazole

41 Ancylostoma duodenale
& Necator americanus

42 Organism: Strongyloides stercoralis Disease: Strongyloidiasis
Geographical Distribution: Worldwide Humid areas with poor sanitation Transmission: Direct penetration of unbroken skin by larva Autoinfection - internal (larva becomes infectious in intestinal tract) & external

43 Strongyloides stercoralis
Location of Parasite: Larva migrates via blood system to lungs, penetrates alveoli, coughed up and swallowed Adult in mucosa of duodenum & jejunum Eggs hatch in intestine Larvae (non-infective) in stool develops into infective larva in soil (Free living cycle in soil)

44 Strongyloides stercoralis
Clinical: Pruritic rash associated with larval entry Coughing & wheezing, High eosinophilia Abdominal pain, diarrhea Hyperinfection - large numbers of larvae Disseminated strongyloidiasis - in other organs (in immunocompromized patients - but not AIDS) Control & Treatment: Ivermectin, thiabendazole

45 Strongyloides stercoralis

46 Strongyloides stercoralis
Morphology: Adult females 2-3 mm

47 Strongyloides stercoralis
Morphology: Larvae nm

48 Strongyloides stercoralis

49 Strongyloides stercoralis

50 Strongyloides stercoralis

51 Strongyloides stercoralis

52 Strongyloides stercoralis
Diagnosis: String Test Baermann concentration Serology & Bacterial agar plate

53 Strongyloides stercoralis


55 Organism: Disease: Geographical Distribution: Transmission: Location of Parasite: Morphology: Clinical: Diagnosis: Control & Treatment:

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