Evaluation of the economic impact of brucellosis in domestic yaks of Tibet.

Brucellosis is considered as an endemic disease in yaks (Bos grunniens) in China, but few economic analyses describing the cost of the disease and potential benefits of control have been reported. The aim of the study was to estimate the economic cost of brucellosis in yaks and the economic value of three control strategies: (a) vaccination; (b) test-and-slaughter; and (c) a combination of vaccination and test-and-slaughter programs in Damxung and Maizhokunggar counties and Pali township of Yadong county in Tibet. Using data from a cross-sectional seroprevalence survey conducted in 2015, combined with financial data, the predicted costs and benefits of the different control strategies were simulated over a 6-year period. The annual estimated cost of brucellosis in yaks within the study area was US$ 521,043 (95% CI: US$ 334,441; US$ 759,862), with an annual average cost per yak estimated at US$ 1.42 (95% CI: US$ 0.91, US$ 2.07). The benefit-cost analysis predicted that vaccination was the most effective control method with a benefit-cost ratio (BCR) of 3.19 (95% CI: 2.17, 4.66) and a net present value (NPV) of US$ 313,355 (95% CI: US$ 157,679, US$ 541,062) over a 6-year period. A sensitivity analysis found the NPV was most sensitive to the loss from a female yak aborting in the vaccination control program. In contrast, the price of yaks that were slaughtered had the largest influence on the NPV for both the test-and-slaughter control program and the combination control program. These estimates provide valuable information and establish a foundation for formulating and implementing cost-effective measures for controlling the disease in yaks on the Tibetan plateau, and more broadly in China.