Investigation of the index case herd and identification of the genotypes ofTheileria orientalisassociated with outbreaks of bovine anaemia in New Zealand in 2012
| Autor: | D.J. Pulford, J J Donald, A. M. J. McFadden, JS Hamilton |
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| Rok vydání: | 2015 |
| Předmět: |
0301 basic medicine
Veterinary medicine Genotype 040301 veterinary sciences Anemia Disease Outbreaks 0403 veterinary science 03 medical and health sciences Theileria Animals Medicine Index case Phylogeny General Veterinary biology business.industry Outbreak 04 agricultural and veterinary sciences General Medicine 030108 mycology & parasitology Ribosomal RNA biology.organism_classification medicine.disease Theileriasis Theileria orientalis Herd Cattle business New Zealand |
| Zdroj: | New Zealand Veterinary Journal. 64:21-28 |
| ISSN: | 1176-0710 0048-0169 |
| DOI: | 10.1080/00480169.2015.1090355 |
| Popis: | On 7 September 2012 the Ministry for Primary Industries was notified of a dairy cow with regenerative anaemia (haematocrit (HCT) 0.08 L/L) in a herd of 465 Jersey-Friesian cross cows (index case herd) in the Northland region of New Zealand. Organisms consistent with Theileria spp. were present in red blood cells on a blood smear. No other causes of anaemia were detected following examination of affected cows. Blood samples collected from 29 randomly selected cows on 26 September 2012 showed that 24 (83%) were anaemic (HCT≤0.24 L/L) and therefore fitted the case definition for bovine anaemia associated with Theileria orientalis infection.Using a T. orientalis type-specific PCR assay that targeted the single subunit rRNA gene, all of six animals tested were positive for T. orientalis type Ikeda. Blood samples collected from clinically affected cattle in 11 subsequent outbreaks from throughout the North Island showed that T. orientalis Ikeda type was a common finding, but mixed infections with Chitose type were also identified. In addition, using a PCR assay that targeted the major piroplasm surface gene, T. orientalis type 5 was detected in one cow from the Waikato region.The presence of T. orientalis type Ikeda, as well as type 5, was confirmed in cattle from outbreaks of bovine anaemia in herds throughout the North Island of New Zealand.Two new types of T. orientalis were identified in this investigation, that were associated with a sudden rise in cases of bovine anaemia. The body of evidence showed that the Ikeda type was implicated as the cause of disease observed in this epidemic. |
| Databáze: | OpenAIRE |
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