title: Economic Analysis of Immunization Strategies for PRRS Control [corrected].
abstract: Porcine reproductive and respiratory syndrome virus (PRRSv) is a swine-specific pathogen that causes significant increases in production costs. When a breeding herd becomes infected, in an attempt to hasten control and elimination of PRRSv, some veterinarians have adopted a strategy called load-close-expose which consists of interrupting replacement pig introductions into the herd for several weeks (herd closure) and exposing the whole herd to a replicating PRRSv to boost herd immunity. Either modified-live virus (MLV) vaccine or live field-virus inoculation (FVI) is used. This study consisted of partial budget analyses to compare MLV to FVI as the exposure method of load-close-expose program to control and eliminate PRRSv from infected breeding herds, and secondly to estimate benefit / cost of vaccinating sow herds preventatively. Under the assumptions used in this study, MLV held economic advantage over FVI. However, sensitivity analysis revealed that decreasing margin over variable costs below $ 47.32, or increasing PRRSv-attributed cost above $18.89 or achieving time-to-stability before 25 weeks resulted in advantage of FVI over MLV. Preventive vaccination of sow herds was beneficial when the frequency of PRRSv infection was at least every 1 year and 9 months [corrected]. The economics of preventative vaccination was minimally affected by cost attributed to field-type PRRSv infection on growing pigs or by the breeding herd productivity level. The models developed and described in this paper provide valuable tools to assist veterinarians in their efforts to control PRRSv.
authors.affiliation: Veterinary Diagnostic and Production Animal Medicine Department, College of Veterinary Medicine, Iowa State University, Ames, Iowa, United States of America.
authors.forename: Daniel C L
authors.initials: DC
authors.lastname: Linhares
authors.affiliation: Swine Health Department, The Maschhoffs LLC, Carlyle, Illinois, United States of America.
authors.forename: Clayton
authors.initials: C
authors.lastname: Johnson
authors.affiliation: Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, Saint Paul, Minnesota, United States of America.
authors.forename: Robert B
authors.initials: RB
authors.lastname: Morrison
mesh_terms: D000818:Animals; D008962:Models, Theoretical; D019318:Porcine Reproductive and Respiratory Syndrome / Q000517:prevention & control*; D019316:Porcine respiratory and reproductive syndrome virus / Q000276:immunology*; D013552:Swine; D014611:Vaccination / Q000191:economics* / Q000379:methods*; D014765:Viral Vaccines / Q000276:immunology*
chemical_list: D014765:Viral Vaccines