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Sheep and goats
First report of fatal tick pyaemia caused by heavy infestation with the red sheep tick, Haemaphysalis punctata and co-infection with Babesia and Theileria species
  1. Michele Macrelli1,
  2. Paul Phipps2,
  3. Liz McGinley3,
  4. Jolyon Medlock3 and
  5. Nicholas Johnson2
  1. 1Animal and Plant Health Agency, Veterinary Investigation Centre Bury Saint Edmunds, Bury Saint Edmunds, UK
  2. 2Animal and Plant Health Agency, Addlestone, Surrey, UK
  3. 3Public Health England, Port Down, Salisbury, UK
  1. Correspondence to Mr Michele Macrelli; michele.macrelli{at}


Tick pyaemia is a disease of sheep characterised by the development of internal abscesses caused by Staphylococcus aureus. The disease is normally triggered by infestation with Ixodes ricinus and can be exacerbated by co-infection with Anaplasma phagocytophilum. Here the authors report the finding of tick pyaemia in a sheep flock suffering from high mortality caused by severe infestation with the red sheep tick, Haemaphysalis punctata. Tick pyaemia was confirmed by gross identification of internal abscesses in two lambs and isolation of S aureus from these lesions, with concurrent identification of H punctata ticks on the carcases. Additionally, Babesia motasi and Theileria luwenshuni were detected by pan-piroplasm PCR in the blood of infested animals including the two sent for postmortem examination.

Anaplasma phagocytophilum was not detected. These findings suggest that infestation with H punctata is capable of inducing tick pyaemia in lambs and that this may be exacerbated by coinfection with piroplasms.

  • ticks
  • theileria<i></i>
  • staphylococcus aureus<i></i>
  • haemaphysalis punctata <i></i>
  • babesia motasi <i></i>
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  • Contributors MM has assisted in the postmortem examination. MM has followed the clinical history of the outbreak and collected epidemiological data of the farm and of the affected animals. The ticks' morphological identification and the molecular examinations were performed by the coauthors.

  • Funding Financial contributions for this investigation were provided by Defra through APHA’s “Scanning surveillance for Small Ruminant Diseases in England and Wales” (ED1100) project.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement All data relevant to the study are included in the article.

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