Transcript campbell_enteric

Enteric Nematodes
Ascaris lumbricoides
Enterobius vermicularis
Trichuris trichiura
Hookworms
Ancylostoma duodenale
Necator americanus
Strongyloides stercoralis
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
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
Ascaris lumbricoides
Location of Parasite
Larvae hatch in GI tract,
penetrate GI wall,
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migrate via lungs &
bronchi back to GI
(Adult stage)
Ascaris lumbricoides
Morphology: Adult, 20-35 cm
Female
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Male
Ascaris lumbricoides
Morphology: Ova
Unfertilized
Fertilized
Embryonated
Infective
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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
Ascaris lumbricoides
Clinical:
Ascaris lumbricoides
Clinical:
Ascaris lumbricoides
Clinical:
Ascaris lumbricoides
Clinical:
Ascaris lumbricoides
Diagnosis:
O&P Test
Control & Treatment:
Mebendazole, albendazole
Ascaris lumbricoides
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
Enterobius vermicularis
Morphology:
Adults are 1 cm
Clinical:
Asymptomatic, vaginal pruritis
No migration, No eosinophilia
Reinfection common
Enterobius vermicularis
Enterobius vermicularis
Enterobius vermicularis
Enterobius vermicularis
Enterobius vermicularis
Enterobius vermicularis
Enterobius vermicularis
Diagnosis: “Scotch” Tape test for eggs
Control & Treatment: Mebendazole
Enterobius vermicularis
Organism: Trichuris trichiura
WHIPWORM
Disease: Trichuriasis
Geographical Distribution:
Worldwide
Transmission:
Ingestion of eggs
Location of Parasite:
Adult embedded in mucosa of cecum,
colon, & rectum
Trichuris trichuria
Morphology: Adult 3-5 cm
Anterior (digestive) end is thin
Posterior (reproductive) end is thick
Trichuris trichuria
Trichuris trichuria
Trichuris trichuria
Clinical:
Light infections - asymptomatic
Heavy infections - diarrhea
bloody diarrhea,
rectal prolapse
Diagnosis:
O&P Test
Control & Treatment: Mebendazole & Albendazole
Trichuris trichuria
Trichuris trichuria
Trichuris trichuria
Organism: Ancylostoma duodenale
& Necator americanus
HOOKWORMS
Disease: Hookworm anemia
Geographical Distribution:
Humid areas with poor sanitation
Transmission:
Direct penetration of unbroken skin by larva
Ancylostoma duodenale
& Necator americanus
Location of Parasite:
Adults attached to mucosa of duodenum
and proximal small intestine
Morphology:
Adults are 1 cm
Ancylostoma duodenale
& Necator americanus
Ancylostoma duodenale
& Necator americanus
Ancylostoma duodenale
Necator americanus
Ancylostoma duodenale
& Necator americanus
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
Ancylostoma duodenale
& Necator americanus
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
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)
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
Strongyloides stercoralis
Strongyloides stercoralis
Morphology:
Adult females 2-3 mm
Strongyloides stercoralis
Morphology:
Larvae 0.2-0.3 nm
Strongyloides stercoralis
Strongyloides stercoralis
Strongyloides stercoralis
Strongyloides stercoralis
Strongyloides stercoralis
Diagnosis:
String Test
Baermann concentration
Serology & Bacterial agar plate
Strongyloides stercoralis
Organism:
Disease:
Geographical Distribution:
Transmission:
Location of Parasite:
Morphology:
Clinical:
Diagnosis:
Control & Treatment: