Allergen: Aspergillus fumigatus

Aspergillus fumigatus is a fungus found in soil survives on organic debris and plays an essential role in recycling environmental carbon and nitrogen. They belong to

  • Kingdom: Fungi
  • Phylum: Ascomycota
  • Class: Eurotiomycetes
  • Order: Eurotiales
  • Family: Trichocomaceae
  • Genus: Aspergillus
  • Species: fumigatus

A. fumigatus is characterised by green echinulate conidia, 2.5 to 3 micron in diameter, produced in chains basipetally from greenish phialides. It sporulates abundantly, with every conidial head

Aspergillus fumigatus

producing thousands of conidia (asexual spores) which are air-borne.

Once the spores are in the air, their small size makes them buoyant, tending to keep them airborne both indoors and outdoors. Furthermore, their small diameter (2-3 micron) makes it possible for them to reach the lung alveoli.

Outdoor habitat: soil, decaying plant materials, trees, compost, wood chips, hay and crops and stored grains.

Indoor habitat: on dampened building materials (plasterboard, wood, chipboard, ceiling tiles, cardboard and insulation material), on indoor organic substrates such as house dust and other cellulose containing materials, in humidifier, air-conditioning systems and air ducts and filters, as well as on household articles made of linen, leather and paper.

They are perennial in nature present pan over india with peak in summer and rains.

Out of about 23 allergenic proteins derived from A. fumigatus Asp f 1, f 2, f 3, f 4, and f 6 are clinically significant.

They have been shown to cross react with A. flavus, A. versicolor, A. niger and also with other fungal genera like P. notatum, Cladosporum herbarum, Alternaria alternata, Penicillium citrinum, Sacchromyces cerevisiae, Fusarium solani and Candida albicans.

Over 80% of Aspergillus-related conditions, such as extrinsic allergic alveolitis, asthma, allergic sinusitis, chronic eosinophilic pneumonia, hypersensitivity pneumonitis, severe asthma with fungal sensitization (SAFS), and Allergic BronchoPulmonary Aspergillosis (ABPA) are caused by A. fumigatus.

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