Economic and epidemiologic implications of national bovine Brucellosis programs : a case study

Abstract

Bovine brucellosis is a reproductive disease that causes abortions, light calves, reduced milk production in cows and undulant fever in humans. Loses in the United States from bovine brucellosis were estimated to exceed 65 million pounds of beef and 35 million pounds of milk in 1976. during that year, 75 million dollars were spent by producers, state and federal authorities to control the spread of brucellosis. Thus, the policies controlling the eradication effort of brucellosis have a major impact on consumers, livestock producers and taxpayers. BRUSIM, a systems simulation model was developed to analyze the epidemiologic and cost ramifications of brucellosis control/eradication programs given epidemiologic coefficients and economic criteria. A base program was simulated to maintain prevalence in a relatively "steady state" and to compare changes in physical losses from alternative programs to the base program. Changes in physical losses attributable to alternative programs were analyzed in a general equilibrium supply and demand model to determine the net benefits accuring to society, consumers, producers and related industries. Alternative programs analyzed included eradication programs, vaccination programs, adjacent herd testing programs and a combined adjacent herd testing-vaccination program. Results revealed that all alternative programs were cost effective in terms of benefit-cost ratios and net benefits. The most cost effective programs were the adjacent herd testing programs followed by eradication and vaccination programs. The use of adjacent herd testing may prove to be very effective in the control and/or eradication of brucellosis. Results indicated that 100 percent adjacent herd testing the MCI detected affected herds reduced disease prevalence and decreased total cost compared to the base model. Vaccination in high incidence regions can be highly cost effective, but high levels of vaccination in low and moderate disease incidence regions did not yield positive net benefits. The eradication models analyzed reduced the disease prevalence to very low levels. However, alternative disease detection techniques may be necessary to achieve final eradication.