Investigation published in Preventive Veterinary Medicine

May 23^rd, 2009

Within the European Union (EU), detailed legislation has been developed for cattle, but not deer, to minimise disease risks associated with trade in animals and animal products. This legislation is expressed as input-based standards, providing a detailed outline of the activity required (for example, testing of animals and application of defined control measures), on the expectation that an adequate output (for example, confidence in freedom) will be achieved. Input-based standards are at odds with the increasing shift towards output-based standards, particularly in OIE rules governing international trade. In this paper, we define output-based standards to achieve and maintain freedom from tuberculosis (TB) in farmed deer, with reference to EU member states. After considering the probability of freedom achieved for cattle under existing EU legislation, we defined a `free farmed deer holding´ as one with a probability of freedom from infection of at least 99%. We then developed an epidemiological model of TB surveillance systems for deer holdings, incorporating different surveillance strategies, including combinations of diagnostic tests, and a variety of different scenarios relating to the potential for introduction of infection. A range of surveillance strategies were identified to achieve and maintain a free farmed deer holding, and worked examples are presented. The surveillance system sensitivity for varying combinations of screening and confirmatory tests in live animals, animals at slaughter and on-farm deaths is also presented. Using a single test at a single point in time, none of the TB tests routinely used in farmed deer is able to achieve an acceptable probability of TB freedom. If repeat testing were undertaken, an acceptable probability of TB freedom could be achieved, with differing combinations of the surveillance system sensitivity, frequency of testing and risk of introduction. The probability of introduction of infection through the importation of infected deer was influenced by the use of a pre-movement test (assumed 90% test sensitivity and negative test results), the TB prevalence in the source herd and the number of animals imported. A surveillance system sensitivity of at least 81% was achieved with different combinations of annual live animal surveillance and surveillance of animals at slaughter or on-farm deaths. This methodology has broad applicability and could also be extended to other diseases in both deer and other species with relevance to trade in animals and animal products

More JS., Cameron AR., Greiner M., Clifton-Hadley RS., Rodeia SC., Bakker D., Salman MD., Sharp JM., De Massis F., Aranaz A., Boniotti MB., Gaffuri A., Have P., Verloo D., Woodford N. and Wierup M.

Defining output-based standards to achieve and maintain tuberculosis freedom in farmed deer, with reference to member states of the European Union

Defining output-based standards to achieve and maintain tuberculosis freedom in farmed deer, with reference to member states of the European Union

	Servicio de Micobacterias (MYC). Centro de Vigilancia Sanitaria Veterinaria (VISAVET). Universidad Complutense (UCM).
	Departamento de Sanidad Animal. Facultad de Veterinaria. Universidad Complutense (UCM).
	UCD School of Agriculture, Food Science & Veterinary Medicine. University College Dublin (UCD).
	AusVet Animal Health Services.
	Federal Institute for Risk Assessment (BfR).
	Veterinary Laboratories Agency. Department for Environment, Food and Rural Affairs (Defra).
	European Food Safety Authority (EFSA).
	Central Institute for Animal Disease Control (CIDC).
	Animal Population Health Institute. College of Veterinary Medicine and Biomedical Sciences. Colorado State University (CSU).
	Pentlands Science Park. Moredun Research Institute.
	Dipartimento di Biologia Molecolare. Istituto Zooprofilattico Sperimentale della Lombardia e dell Emilia Romagna (IZSLER).
	Sezione Diagnostica di Bergamo. Istituto Zooprofilattico Sperimentale della Lombardia e dell Emilia Romagna (IZSLER).
	Department of Biomedical Sciences and Veterinary Public Health. Swedish University of Agricultural Sciences (SLU).