This document summarizes Aspergillus, a ubiquitous fungus with several species that can cause disease in humans. It describes the morphology and life cycle of Aspergillus, noting that its airborne conidia can reach the lungs and cause infection in immunocompromised individuals. It outlines the different clinical forms of aspergillosis, including allergic forms and risk factors. Diagnosis involves microscopy and culture of specimens. Treatment involves antifungal drugs like itraconazole and amphotericin B. Prevention focuses on avoiding exposure to conidia for at-risk groups.

2.  Ubiquitous
 Worldwide
TYPES:
A fumigatus
A flavus
A niger
A terreus
A lentulus

3.  Rapid growth
 Basic morphology:
 Aerial hyphae with conidia; long
conidiophores with terminal vesicles on
which phialides produce biseptal chain
of conidia
 Species variate in these

7.  Fungal conidia formed in abundance
 Aerosolized
 Reach lungs
 Macrophages can engulf & destroy conidia
IMMUNOCOMPROMISED:
Leukaemia, stem cell transplant,
corticosteroids
Macrophages cannot contain inoculum;
Conidia swell, germinate to hyphae in
cavities, BV

8. ALLERGIC FORMS:
1.IgE AB formed to As conidial Ag
 Second exposure: immediate asthama
2. Allergic Bronchopulmonary Aspergillosis
 Conidia germinate,hyphae colonize
bronchial tree; parenchyma spared;


9. Inhaled enter an existing cavity,
germinate to abundant hyphae in
abnormal space as in TB, sarcoidosis,
emphysema
 Asymptomatic
 Cough, dysponea, hemoptysis, fatigue,
weight loss
 Invade nasal sinuses, cornea, nail, ear
canal

10.  Asthama
 Recurrent chest infilterates
 Eosinophilia
 Both type 1 & 3 hypersensitivity reaction
 Permenant lung scarring
3.Extrinsic Allergic Alveolitis:
Normal individuals with massive conidial
exposure

11.  Inhalation; germination
 Acute pneumonic process: mild necrosis to
 Dissemination +/-
RISK: Immuno-compromised:
 AIDS; CD4 count< 50cells/mm
 Stem cell allogenic hemopoietic transplant
 Leukaemia/lymphoma
 Corticosteroid therapy

12. Specimen:
 Sputum
 Lung biopsy
 Resp tract specimen
Microscopy: KOH mount
 calcofluor stain
 histology
 Hyphae: 4um wide, septate,hyaline,
branch dichotomously

13.  Fever, cough, dysponea, hemoptysis
 Hyphae invade BV; lumen & wall to
cause thrombosis, infarction & necrosis
Dissemination to organs
 GIT& Liver
 Kidney
 Brain
FATE: grave without T/M

16.  ID test positive
 AB: no help
 Cell wall galactomannan may help
T/M:
 Itraconazole; posaconazole Amp R in leukamia centres
 Amphotericin B
 Cytokine immuotherapy: interferon/gran-mac colony
Stimu
 Allergic: steroids, disodium chromoglychate
Prevention
 Avoid exposure to conidia in allergic & IC uhospital units