PMID- 26515925 OWN - NLM STAT- MEDLINE DCOM- 20170203 LR - 20170203 IS - 0048-0169 (Print) IS - 0048-0169 (Linking) VI - 64 IP - 1 DP - 2016 Jan TI - An assessment of the herd-level impact of the Theileria orientalis (Ikeda) epidemic of cattle in New Zealand, 2012-2013: a mixed methods approach. PG - 48-54 LID - 10.1080/00480169.2015.1090893 [doi] AB - AIM: To estimate incidence risk, cumulative mortality and case fatality rate within herds affected by bovine anaemia associated with Theileria orientalis infection (TABA), in New Zealand during the early phase of the epidemic (August 2012-September 2013). METHODS: A mixed methods approach was utilised to integrate data from various sources, including a detailed questionnaire carried out on 18 dairy farms which had experienced cases of TABA; a brief telephone survey of an additional 139 case farms; and data extracted from a Ministry for Primary Industries database for a further 42 case farms. The subsequent analysis determined incidence risk, cumulative mortality and case fatality rates for beef and dairy herds. RESULTS: Data were analysed from 196/263 (74%) known case farms at the date of closing the questionnaires. These farms contained 99,505 cattle; 2,847 animals were reported with clinical disease, and a further 590 animals were recorded as having died from TABA. The within-herd incidence risk, cumulative mortality and case fatality rate were consistent between the three data sources, did not differ between beef and dairy herds, and were estimated to be 0.97 (inter-quartile range (IQR) 0.36-2.07)%, 0.23 (IQR 0.00-0.66)% and 16.67 (IQR 0.00-33.33)%, respectively. There was substantial variability in the level of impact, with 22 farms severely affected (incidence risk >5% and cumulative mortality >5%). CONCLUSIONS: The mixed methods approach was effective in dealing with the disparate data sources. The inclusion of the majority of farms known to be affected at the time the questionnaires were performed implies that the information is likely to be representative. The collective outputs of the analyses represent the best estimate available of within-herd measures of disease frequency in the early phase of the epidemic in New Zealand. The limitations of the data imply that their primary application may be to inform the design of subsequent structured observational field studies. CLINICAL RELEVANCE: The results of this study provide information on the impact of TABA on cattle farms during the emergence and early spread of the disease, as well as for generating hypotheses on causal mechanisms and risk factors that may influence the course of disease. FAU - Vink, W D AU - Vink WD AD - a Ministry for Primary Industries , 66 Ward Street, Wallaceville, Upper Hutt , 5018 , New Zealand. FAU - Lawrence, K AU - Lawrence K AD - b Institute of Veterinary, Animal and Biomedical Sciences , Massey University , Palmerston North , New Zealand. FAU - McFadden, Amj AU - McFadden A AD - a Ministry for Primary Industries , 66 Ward Street, Wallaceville, Upper Hutt , 5018 , New Zealand. FAU - Bingham, P AU - Bingham P AD - a Ministry for Primary Industries , 66 Ward Street, Wallaceville, Upper Hutt , 5018 , New Zealand. LA - eng PT - Journal Article DEP - 20151030 PL - England TA - N Z Vet J JT - New Zealand veterinary journal JID - 0021406 SB - IM MH - Anemia/epidemiology/mortality/parasitology/*veterinary MH - Animals MH - Cattle MH - New Zealand/epidemiology MH - Theileria/*classification MH - Theileriasis/epidemiology/mortality/*pathology OTO - NOTNLM OT - TABA OT - Theileria orientalis (Ikeda) OT - anaemia OT - mixed methods research OT - theileriosis OT - within-herd disease frequency EDAT- 2015/10/31 06:00 MHDA- 2017/02/06 06:00 CRDT- 2015/10/31 06:00 PHST- 2015/10/31 06:00 [entrez] PHST- 2015/10/31 06:00 [pubmed] PHST- 2017/02/06 06:00 [medline] AID - 10.1080/00480169.2015.1090893 [doi] PST - ppublish SO - N Z Vet J. 2016 Jan;64(1):48-54. doi: 10.1080/00480169.2015.1090893. Epub 2015 Oct 30.