Discovery and application of novel antimicrobials against the protozoan Histomonas meleagridis
: The causative agent of Histomonosis in poultry

Student thesis: Doctoral ThesisDoctor of Philosophy


Histomonas meleagridis is a protozoan and the causative agent for Histomonosis or as commonly referred to blackhead disease. There have been treatments for H. meleagridis however the treatments have steadily been banned until the last one was removed in 2014 in the USA. The removal of the last therapeutic drug has resulted in a rapid rise in H. meleagridis and consequently incidences of blackhead disease and in turn this has caused an increase of research into the pathogen.

This study main aim was to test Antimicrobial peptides efficacy on H. meleagridis. Before that culturing and detection had to be tested first. It was found that the culturing at 39-40C in anaerobic conditions with either serum tested proved the most reliability conditions. The study tested a range of published H. meleagridis PCR primers. It was found that there was found that the Primers tested either did not amplify an amplicon at the correct size or produced amplicons for samples which did not contain H. meleagridis. To try and help with future detection there was an attempted to sequence the genome. There was issues with this and contamination plagued the isolation and sequencing of the genome resulting in only 5% of the genome being sequenced.

In total 82 AMPs were tested successfully this was though developing a method for high throughput testing of compounds for microbes which cannot be cultivated in isolation using microscopy. 16 AMPs had a lower susceptible concentration compared to the last control compound and will be investigated further. Rumen derived AMPs were tested to directly affect H. meleagridis with activity at the same concentration in the initial testing. In conclusion the study has identified and potentially found a way to treat H. meleagridis, which now requires in vivo confirmation.

Thesis embargoed until 31 December 2024.
Date of AwardDec 2021
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SponsorsBritish Poultry Council
SupervisorSharon Huws (Supervisor), Chris Creevey (Supervisor) & Nigel Scollan (Supervisor)


  • Protoza
  • antimicrobial peptides (AMPs)
  • histomonas meleagridis
  • histomonosis
  • poultry
  • PCR
  • genomics
  • treatment

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