Recent studies on aspergillosis in turkey poults

Area of Science:

• Veterinary Mycology
• Poultry Disease Research
• Fungal Pathogenesis

Background:

• Aspergillosis is a significant concern in turkey poults.
• Studies at the National Animal Disease Center focused on field observations, pathogenicity, and vaccine development for avian aspergillosis.

Purpose of the Study:

• To evaluate the efficacy of natural ventilation in reducing fungal spore loads in turkey houses.
• To compare the pathogenicity of Aspergillus fumigatus and Aspergillus flavus in turkey poults.
• To assess the effectiveness of a vaccine developed from Aspergillus fumigatus germlings.

Main Methods:

• Assessing ventilation effectiveness by measuring airborne fungal propagules.
• Conducting aerosol exposure studies with turkey poults using A. fumigatus and A. flavus.
• Evaluating vaccine efficacy through challenge exposure to A. fumigatus spores.

Main Results:

• Natural ventilation reduced airborne fungal propagules but was limited by building width.
• A. fumigatus caused higher mortality than A. flavus in aerosol-exposed poults.
• Toxigenicity of A. flavus did not increase pathogenicity, and aflatoxin was not detected during infection.
• A. fumigatus spores disseminated rapidly, with alveolar macrophages containing spores post-exposure.
• Vaccines derived from A. fumigatus germlings showed the highest efficacy against A. fumigatus spore challenge.

Conclusions:

• A. fumigatus poses a greater mortality risk to turkey poults than A. flavus.
• Vaccination with A. fumigatus germlings is a promising strategy for controlling aspergillosis in poultry.
• Ventilation strategies should consider building dimensions for optimal fungal spore reduction.