Ausbrüche von Histomonose bei langsamer wachsenden Putenlinien

Histomonosis or Blackhead Disease is a poultry disease caused by infection with the protozoan parasite Histomonas meleagridis. Outbreaks are most frequent in turkey flocks, with often high mortality rates of up to 100%. During a study with three slower growing turkey strains on an organic farm in the years 2015 to 2018, in all three fattening batches outbreaks of histomonosis occured. The disease was diagnosed histologically by PAS-staining, in some cases PCR detection was performed. Heterakis gallinarum could not be detected in fecal samples using the flotation method. Remarkable were the relatively low average mortality rates of 0.7–3.5% caused by the disease. Mortality rates did not significantly differ between the turkey strains. Furthermore, the infection route could not be conclusively clarified, but an uptake in the free range was likely.