Protozoan DNA in enviromental dust samples from turkey flocks. Dust samples from turkey flocks

The present report documents the testing of environmental dust samples obtained from 65 turkey flocks in France, of which 6 suffered from histomonosis, for the presence of H. meleagridis DNA. Samples were screened for H. meleagridis by recently developed real-time PCR based on the 18S rRNA locus. Positive samples were further analyzed sequencing 18S rRNA locus. Additionally, production data of all tested flocks such as average daily gain (ADG), feed conversion ratio (FCR) and production index (PI) were statistically evaluated and compared to see the effect of eventually positive dust samples in clinically unaffected flocks. Results: Histomonad DNA was detected in the dust obtained from all 6 clinically affected and, surprisingly, in 9 unaffected flocks. ADG and PI were negatively affected in flocks with clinical histomonosis resulting in significant difference in comparison with the data obtained from clinically healthy flocks independent of the presence of histomonad DNA in the dust. Overall, there was no significant difference following statistical analysis of production parameters between the two last mentioned groups of tested flocks.Conclusions: Altogether, this is the first investigation demonstrating the presence of H. meleagridis DNA in environmental dust samples obtained from clinically unaffected turkey flocks. The presence of histomonad DNA could not be correlated with impact on production, thus minimizing the possibilities that the dust could serve as a mechanical vector for transmission of the disease. However, the actual data indicate that H. meleagridis is much more widespread in turkey flocks than expected upon mortality and pathological lesions.