The disease · Animal health & welfare
Blackhead Disease is a re-emerging disease in turkeys and has currently no licensed prophylactic or therapeutic option
Following the withdrawal of efficacious drugs in certain countries blackhead disease (histomonosis) has resurfaced as one of the most serious unmet needs in poultry health, characterized by animal suffering and compromised welfare. Mortality and production losses are a significant threat for farmers.
The pathogen
Histomonas meleagridis
A protozoan parasite - a flagellate - with a complex biology and the causative agent of blackhead disease. A well-defined monoxenic attenuated clonal culture is the basis for our vaccine and the focus of our scientific work.
The disease
Blackhead disease
syn. Histomonosis · Histomoniasis
Once well controlled, blackhead disease has re-emerged following the withdrawal of efficacious drugs. The clinical picture is severe and the production impact is substantial — yet no licensed prophylaxis or therapy is currently available.
Academic Publications
Research and References
Selected references with focus on the development of histoVAC.
Hess, M., Kolbe, T., Grabensteiner, E. and H. Prosl (2006)
Clonal cultures of Histomonas meleagridis, Tetratrichomonas gallinarum and a Blastocystis sp. established through micromanipulation.
Parasitology 133, 547-554; https://doi.org/10.1017/s0031182006000758
Hess, M., Liebhart, D., Grabensteiner, E. and A. Singh (2008)
Cloned Histomonas meleagridis passaged in vitro resulted in reduced pathogenicity and is capable to protect turkeys from histomonosis.
Vaccine 26, 4187-4193; https://doi.org/10.1016/j.vaccine.2008.05.071
Liebhart, D., Windisch, M. and M. Hess (2010)
Oral vaccination of 1-day-old turkeys with in vitro attenuated Histomonas meleagridis protects against histomonosis and has no negative effect on performance.
Avian Pathol. 39, 399-403; https://doi.org/10.1080/03079457.2010.506906
Liebhart, D., Zahoor, M.A., Prokofieva, I. and M. Hess (2011)
Safety of avirulent histomonads to be used as a vaccine determined in turkeys and chickens.
Poult. Sci. 90, 996-1003; https://doi.org/10.3382/ps.2010-01255
Ganas, P., Liebhart, D., Glösmann, M., Hess, C. and M. Hess (2012)
Escherichia coli strongly supports the growth of Histomonas meleagridis, in a monoxenic culture, without influence on its pathogenicity.
Int.J.Parasitol. 42, 893-901; https://doi.org/10.1016/j.ijpara.2012.07.007
Sulejmanovics, T,. Liebhart, D. and M. Hess (2013)
In vitro attenuated Histomonas meleagridis does not revert to virulence, following serial in vivo passages in turkeys or chickens.
Vaccine, 31, 5443-5450; https://doi.org/10.1016/j.vaccine.2013.08.098
Hess, M., Liebhart, D., Bilic, I. and P. Ganas (2015)
Histomonas meleagridis – new insights into an old pathogen.
Vet. Parasitol. 208, 67-76; https://doi.org/10.1016/j.vetpar.2014.12.018
Sulejmanovic, T., Hess, M. and D. Liebhart (2016)
An in vitro attenuated strain of Histomonas meleagridis provides cross-protective immunity in turkeys against heterologous virulent isolates.
Avian Pathol. 45, 46-53; https://doi.org/10.1080/03079457.2015.1117057
Liebhart, D., Ganas, P., Sulejmanovic, T. and M. Hess (2017)
Histomonosis in poultry: previous and current strategies for prevention and therapy.
Avian Pathol. 46, 1-18; https://doi.org/10.1080/03079457.2016.1229458
Gruber, J., Ganas, P. and M. Hess (2017)
Long term in vitro cultivation of Histomonas meleagridis coincides with the dominance of a very distinct phenotype of the parasite exhibiting increased tenacity and improved cell yields.
Parasitol. 144, 1253-1263, https://doi.org/10.1017/s0031182017000646
Mitra, T., Gerner, W., Kidane, F., Wernsdorf, P., Hess, M., Saalmüller, A. and D. Liebhart (2017)
Vaccination against histomonosis limits pronounced changes of B cells and T-cell subsets in turkeys and chickens.
Vaccine 35, 4184-4196; https://doi.org/10.1016/j.vaccine.2017.06.035
Monoyios, A., Patzl, M., Schlosser, S., Hess, M. and I. Bilic (2018)
Unravelling the differences: comparative proteome analysis of a clonal virulent and an attenuated Histomonas meleagridis strain.
Int. J. Parasitol. 48, 145-157; https://doi.org/10.1016/j.ijpara.2017.08.017
Mitra, T. Kidane, F.A., Hess, M. and D. Liebhart (2018)
Unravelling the immunity of poultry against the extracellular protozoan parasite Histomonas meleagridis, is a cornerstone for vaccine development: a review.
Front. Immunol. 9:2518 ID:91034; https://doi.org/10.3389/fimmu.2018.02518
Kidane, F.A., Mitra, T., Wernsdorf, P., Hess, M. and D. Liebhart (2018)
Allocation of interferon (IFN)-gamma mRNA positive cells in caecum hallmarks a protective trait against histomonosis.
Front. Immunol. 9:1164; https://doi.org/10.3389/fimmu.2018.01164
Bilic, I. and M. Hess (2020)
Interplay between Histomonas meleagridis and bacteria: mutualistic or predator-prey?
Trends Parasitol. 36, 232-235; https://doi.org/10.1016/j.pt.2019.12.015
Palmieri, N., Ramires M.J., Hess, M. and I. Bilic (2021)
Complete genomes of the eukaryotic poultry parasite Histomonas meleagridis: linking sequence analysis with virulence / attenuation.
BMC Genomics 22, 753; https://doi.org/10.1186/s12864-021-08059-2
Hatfaludi, T., Rezaee, M.S., Liebhart, D., Bilic, I., and M. Hess (2022)
Experimental reproduction of histomonosis caused by H. meleagridis genotype 2 in turkeys can be prevented by oral vaccination of day-old birds with a monoxenic genotype 1 vaccine candidate.
Vaccine 40, 4986-4997; https://doi.org/10.1016/j.vaccine.2022.07.001
Hatfaludi T., Rezaee, M.S., Vlerick, L., Sulejmanovic, T., de Gussem M., Vereecken, M., de Gussem, K., Liebhart D. and M. Hess (2025)
Long-term protection of turkeys with a live clonal monoxenic Histomonas meleagridis vaccine.
Avian Pathol. 54, 633-644; https://doi.org/10.1080/03079457.2025.2497814