MODELING FOR COST ANALYSIS OF JOHNE'S DISEASE CONTROL BASED ON EVELISA TESTING

Abstract

Use of enzyme-linked immunosorbent assay (ELISA) is recommended for control of Johne's disease (JD) in the cattle industry. A recent report showed that prevalence of JD in dairy farms could be reduced by applying an ELISA-based control strategy, even though the sensitivity of the current ELISA has been reported to be lower than 30%. We previously developed a more sensitive ELISA test (EVELISA; Ethanol Vortex ELISA) for diagnosis of JD and, in this report, aimed to evaluate cost-effectiveness of the EVELISA in JD control compared to that of a current ELISA test. For simulation of population dynamics, we developed a deterministic, discrete-time mathematical model incorporating contact structure, possibility of adult infection and the concept of order of events. In our model, the number of animals infected with the causative agent of JD, Mycobacterium avium subsp. paratuberculosis (MAP), increases in a 10-year simulation if no JD control measure is applied. When test results of ELISA or EVELISA are used for JD control, the increase in MAP-infected animals is less significant. According to our model, EVELISA-based control measures increase the annual per capita revenue of US dairy farms when compared to no JD control and ELISA-based JD control, respectively.