The aim of this study was to determine the pathological, mycological and molecular findings in turkey poults with different immunological status experimentally infected with Aspergillus fumigatus. The investigation was carried out 1, 3, 7, 14 and 21 days after intratracheal inoculation of 5.056×107 spores of A. fumigatus to 14-day-old turkey poults in group G-1, as well as to turkey poults in group G-2 which were treated prior to infection with dexamethasone. A. fumigatus was isolated on day 1 p.i. in both groups, but the number of positive samples was bigger in group G-1. A. fumigatus was isolated from the respiratory organs of group G-1as early as on day 1 and 3 p.i. in 4 out of 12 examined specimens (33%). On day 7 p.i. A. fumigatus was possible to isolate from the respiratory organs of 50% of infected birds, on day 14 in 83.33% and on day 21 p.i. A. fumigatus was isolated in 6 out of 6 sacrificed turkey poults (100%). In dexamethasone-treated group A. fumigatus isolates from the respiratory organs on day 1 and 3 p.i. were same as in group G-1, whereas on days 7 and 14 p.i. the number of turkey poults positive to A. fumigatus increased in comparison with the untreated G-1 group. The histopathological lesions in turkey poults treated with dexamethasone developed earlier, were more intensive and extensive. The mycological and nested PCR results revealed a higher number of samples positive for the presence of A. fumigatus DNA in the group G-2, pretreated with dexamethasone.
