961
Views
109
CrossRef citations to date
0
Altmetric
Clinical Communications

An outbreak of haemolytic anaemia associated with infection of Theileria orientalis in naïve cattle

, , , , , , , & show all
Pages 79-85 | Received 13 May 2010, Accepted 22 Nov 2010, Published online: 15 Mar 2011
 

Abstract

CASE HISTORY: An outbreak of haemolytic anaemia occurred when 87 cattle were introduced from a presumed non-infected herd from south Otago to a herd in Northland (n=580 cows), New Zealand, where theileriosis is endemic.

CLINICAL FINDINGS: Clinical signs associated with Theileria spp. infection included lethargy, anorexia, inappetance, pale mucous membranes, and varying severity of anaemia. In the naïve imported cattle, 11/29 (38%) of those tested showed haematological signs of anaemia (haematocrit (HCT) <0.25 L/L). A negative association was present between the HCT and the number of Theileria spp. organisms counted using light microscopy (correlation coefficient=−0.4; p<0.05).

Haemoparasites consistent with Theileria spp. were observed on examination of a blood smear. Theileria orientalis group (Theileria buffeli/orientalis) species was confirmed using PCR and DNA sequencing, and other causes for anaemia were excluded in the most clinically severely affected cow. The 18S sequence data and phylogenetic analysis of the CoxIII sequences showed samples had the greatest similarity to T. orientalis Chitose from Japan.

DIAGNOSIS: Haemolytic anaemia associated with infection of T. orientalis.

CLINICAL RELEVANCE: Previous reports have suggested that T. orientalis group species may be non-pathogenic in healthy cattle, and an incidental finding in blood samples. However, this investigation provided evidence that in New Zealand, this pathogen is capable of causing clinical disease in cattle not necessarily debilitated by another disease. The potential for disease should be considered when naïve cattle are brought in from non-endemic to endemic regions, for instance cattle from the South Island moved to regions where the vector for T. orientalis group species, Haemaphysalis longicornis, is active, and T. orientalis is present.

Acknowledgements

The authors would like to thank laboratory staff and other members of the Incursion Investigation Team at the IDC for their contribution to this investigation; the referring veterinarian; the owner of the affected farm, who graciously complied with every request from the IDC; Kevin Metcalf, who carried out the majority of haematology work (Gribbles Veterinary Pathology, Auckland); Matt Playford, Dawbuts Pty Ltd, NSW, Australia, who provided a selection of key references; and Cayla Beth McFadden, who provided comments on the manuscript.

Notes

1 J Gill, Gribbles Veterinary Pathology, Mosgiel, New Zealand

*Non-peer-reviewed

*Non-peer-reviewed

Log in via your institution

Log in to Taylor & Francis Online

PDF download + Online access

  • 48 hours access to article PDF & online version
  • Article PDF can be downloaded
  • Article PDF can be printed
USD 61.00 Add to cart

Issue Purchase

  • 30 days online access to complete issue
  • Article PDFs can be downloaded
  • Article PDFs can be printed
USD 213.00 Add to cart

* Local tax will be added as applicable

Related Research

People also read lists articles that other readers of this article have read.

Recommended articles lists articles that we recommend and is powered by our AI driven recommendation engine.

Cited by lists all citing articles based on Crossref citations.
Articles with the Crossref icon will open in a new tab.