Histoplasmosis

Pathogen

• Histoplasma capsulatii
• Histoplasma duboisii in Africa
• dimorphic fungus
• incubation 1-4 weeks
• recurrence/reactivation in years or even in decades
• bat and birds are reservoir
  • bat guano through cave exploration is at very high risk
  • chicken and pigeons

Distribution

• US
• South East Asia
• Africa

Clinical features

• acute pulmonary histoplasmosis
  • most common
  • mostly self-limited
• chronic pulmonary histoplasmosis
  • completely different form from acute ones
  • COPD at risk
  • fibrosing pneumoitis
  • adrenal infection causing adrenal failure
  • progressive to respiratory failure
• disseminated histoplasmosis
  • immunocompromised at risk
  • affecting multiple organs
• ocular histoplasmosis
  • chronic chorio-retinitis
  • controversial whether this is truly histoplamosis or not
• African histoplasmosis by H. duboisii
  • different clinical pictures from H. capsulatii

Diagnosis

• culture is not so much biohazardous

Treatment

• basically itraconazole is the first-line
• differs depending on disease forms