Common Clinical Presentations of Parasitic Infections

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Common Clinical Presentations of Parasitic
Infections

• Parasites causing this clinical presentation
• How did the parasite produce this presentation
  (Pathogenesis)
• Mode of infection

• Jaundice

• Bronchial asthma

• Diarrhoea

• Appendicitis

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Jaundice
Yellowish coloration of skin and sclera with high
bilirubin level in blood

• Fascioliasis
• Schistosomiasis.
• Hydatid disease.
• Ascariasis.
• Amoebiasis.
• Toxoplasma.
• Falciparum malaria

Cell damage
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How can P.falciparum infection cause jaundice?
Blood Vessel of the infected patient
Auto-antibodies
Normal RBCs
Infected RBCs
The produced (autoantibodies) will cross-react
with host RBCs
Haemolysis of RBCs haemolytic anaemia
Haemoglobinuria
The patient suffers from jaundice
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Mode of Infection with Toxoplasma
1- Oral route (ingestion)
Contaminated food or drink
Sporulated oocyst
Handling cat excreta
Infected undercooked meat
Tissue cyst
Pseudocyst
2- Organ transplantation
Tachyzoites
3- Blood transfusion
4- Transplacental route
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Mode of Infection
5- Contamination of mucous membrane skin
abrasion (in research workers
butchers)
Tachyzoites
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Bronchial asthma

• Means difficulty in breathing
• Parasitic infections that may be associated with
  bronchial asthma
• 1- Fascioliasis.
• 2- Ascariasis.
• 3- Ancylostomiasis.
• 4- Visceral larva migrans.
• 5- Bodies of living and dead mites and their
  excreta.

Cause of bronchial asthma An allergic reaction
to parasite antigens and metabolites Mediated by
IgE
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How can Parasites Produce Bronchial asthma?
Allergic dermatitis ?
Eosinophilic pneumonia
Helminths antigens metabolic byproducts
Fab
IgE is produced
Fc
Receptor for IgE
Eosinophil
Become activated
Receptor for IgE
Mast cell
Produce
Broncho-spasm
Pneumonitis
Urticaria
Mediators (substances)
Become activated
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Appendicitis

• Means inflammation of appendix
• Parasitic infection that may be associated with
  appendicitis
• Helminthic infections
• 1- Taenia saginata infection.
• 2- Enterobius vermicularis infection.
• 3- Ascaris lumbricoides infection.
• 4- Trichuris trichiura infection.
• Protozoal infections
• 1- Entamoeba histolytica infection.
• 2- Balantidium coli infection.

Gravid segment
Trophozoite stage
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Diarrhoea
Increase in frequency, fluidity or volume of
bowel motions
Parasitic infections associated with diarrhoea

• - Heterophyiasis
• All tape worm infections
• Ancylostomiasis
• Ascariasis
• Strongyloidiasis
• Trichinosis
• Capillariasis
• Giardiasis
• Cryptosporidiosis, Cylosporiasis, Isosporiasis.

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Mode of Infection
Insufficiently salted and grilled fish (encysted
metacercaria)
Ancylostoma and Strongyloides
Heterophyes heterophyes
T.Spiralis (encysted larva)
C. philippinensis (infective larva in fish
intestine)
Ascaris, Giardia, Cryptosporidium
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Mode of Infection of Tape worms
Beef (cysticercus bovis)
Pork (cysticercus cellulosae)
T.saginata
Salmon (plerocercoid larva)
T.solium
D.latum
Rat flea (cysticercoid nana, diminuta)
D.caninum
H.nana, H.diminuta
Dog flea (cysticercoid caninum)
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Stool Examination for helminths causing diarrhoea
reveals
Heterophyes egg
Capillaria egg
Ancylostoma egg
Fetilized unfertilized Ascaris egg
H.nana egg
H.diminuta egg
Taenia egg or segment
Strongyloides larva
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Stool Examination for Protozoa causing diarrhoea
By MZN stain
G.Lamblia cyst
By immunofluorescence
G.Lamblia trophozoite
Cryptosporidium oocysts
Unstained
Intestinal Microsporidia (1.2x5µ)
By MZN stain
Cyclospora oocysts
Unstained
By MZN stain
Isospora belli oocyst
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Complications

• Amoeboma.

• Perforation of ulcer.

• Haemorrhage.

• Stricture of colon.

• Appendicitis

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Haematogenous spread of Entamoeba trophozoites
Brain abscess
Trophozoite
Lung abscess
Histolytic enzymes
Skin abscess
Liver abscess
Blood vessel
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Give reason
Schistosoma can evade the immune system
Patients RBCs
Schistosoma can evade the immune system by
- antigen disguise.
- antigen mimicry.
Similar to patients antigens
- antigen shedding.
- Cause inactivation of complement by protease
activity.
eosinophil
Mast cell
- Produce blocking antibodies.