Difference between revisions of "Histoplasmosis"

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Image:Histoplasmosis tuberculate chlamydospores.jpg|<center><p>'''Histoplasmosis tuberculate chlamydospores'''</p><sup>Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath</sup></center></gallery>
 
Image:Histoplasmosis tuberculate chlamydospores.jpg|<center><p>'''Histoplasmosis tuberculate chlamydospores'''</p><sup>Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath</sup></center></gallery>
 
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*Caused by [[Yeast-like fungi|''Histoplasma capsulatum'']]
 
*Gross lesions in lungs:
 
**Firm encapsulated granulomas ([[Granulomatous Pneumonia|granulomatous pneumonia]])
 
*Microscopic lesions:
 
**Macrophages with inracytoplasmic yeasts
 
*Also in other tissues
 
 
==Test yourself with the Systemic Mycoses Flashcards==
 
 
[[Systemic_Mycoses_-_Flashcards#Histoplasmosis|Histoplasmosis Flashcards]]
 
 
 
 
[[Category:Systemic_Mycoses]]
 
[[Category:Systemic_Mycoses]]
[[Category:To_Do_-_Clinical]]
+
[[Category:To_Do_-_Fungi]]
[[Category:Respiratory Fungal Infections]]
 

Revision as of 11:28, 25 June 2010

  • Histoplasma capsulatum
  • Non-contageous, systemic mycosis
  • Commonly pulmonary infections occur
    • Other organs can be involved
    • Involves the reticuloendothelial system
    • Intestinal form can also occur
  • Acute and chronic disease can occur
  • Endemic to the USA
    • Isolated cases have been reported in Europe
  • Respiratory infection
    • Infection via ingestion can also occur
  • Affects dogs, cats, cattle, horses and humans
  • Found in soil contaminated by bird droppings, decaying vegetation and in caves inhabited by bats
  • Fine, branching, septate hyphae with smooth-walled pyriform to spherical microconidia and large, thick-walled tuberculate macroconidia on simple conidiophores
  • Dimorphic fungi
  • Hard to demonstrate in smears as the organisms is very small
    • Stain with Giemsa or Wright and examine under oil immersion lens
  • Present intracellularly in macrophages as oval yeast cells with few buds
    • Clear halo is seen around the darker staining central material
  • Grows on Sabouraud's Dextrose agar
    • Creamy white colonies, turning tan coloured and then brown
  • Also grows on Blood agar
    • Small, white yeast-like colonies
  • Test using immunodiffusion, complement fixation and counterimmunoelectrophoresis
    • Skin test of little value as it only indicates exposure
  • The prognosis is poor in acute and disseminated cases