Aspergillus fumigatus infection remains a major cause of economic losses in turkey industry. To elucidate the epidemiology of the different forms of avian aspergillosis, a 16-week surveillance program was started for the detection and genotyping of A. fumigatus isolates in a turkey confinement house. We used genotyping based on the amplification of two polymorphic microsatellite markers (PMMs). Globally, 114 isolates from animals (1-6 isolates/animal) and 134 from air samples were collected and genotyped. During the study, 10 one-day old chicks and 20 adult turkeys were sacrified. Two additional animals were obtained after carcass condemnation for aspergillosis at slaughter inspection. Each of these two animals was infected by a unique but distinct A. fumigatus genotype. In contrast, healthy turkeys older than one day harbored several combinations of genotypes. Surprisingly, all one-day old chicks carried the same unique genotype, confirmed with two additional PMMs, strongly suggesting a massive and common source of contamination in the hatchery. A total number of 134 isolates representing 53 distinct genotypes were obtained from air samples. Thirty three (62.3%) genotypes were observed only once. The remaining 20 environmental genotypes were detected during several weeks with a maximum persistence of 8 weeks. This result confirmed the high diversity of environmental A. fumigatus populations. Ten genotypes were detected both in animals and in air samples. The present study demonstrated the absence of specific pathogenic genotypes in turkeys. PMM analysis was confirmed to be a powerful and convenient tool to investigate genetic epidemiology of A. fumigatus.
Full conference title:
The 15 th Congress of the International Society for Human and Animal Mycology
- ISHAM 15th (2003)