Porcine Reproductive and Respiratory Syndrome (PRRS) Virus
Publish Date: April 29, 2022
Clinical outbreaks characterized by severe reproductive losses, respiratory disease, reduced growth, and increased mortality appeared in the United States in 1987 and then Europe in 1990. In 1991, researchers in the Netherlands determined the cause to be a previously unrecognized virus which they named "porcine reproductive and respiratory syndrome virus" (PRRSV) (Terpstra et al., 1991; Wensvoort et al., 1991). Today, PRRSV is present in most swine-producing regions of the world. PRRSV typically enters herds by the introduction of infected animals, virus-contaminated semen, aerosol spread, or breaks in biosecurity. Once infected, PRRSV tends to circulate in the herd indefinitely. This process is driven by persistent PRRSV infections (carrier animals) and the availability of susceptible animals introduced into the population through birth or purchase. In Europe and North America, the cost of PRRSV was estimated at $6.25 to $15.25 USD per pig marketed (Holtkamp et al. 2013; Nathues et al. 2017). Thus, PRRSV has a major impact on swine health and productivity, but consistent control in the field is difficult.
Evaluation of the effects of immune system activation versus disease on pig growth
Publish Date: September 18, 2006
Purdue University 1996 Swine Research Report. Management programs for improving the health status of pigs have been developed and are being refined. Examples of these technologies include all-in, all-out production, offsite nurseries and grow-finish units, and medicated early weaning programs. These health management programs produce differences in the duration and intensity of individual and combined diseases as well as the animal's immune system response to antigens. In most cases, immune system responses are a reflection of the disease status. The effects of initial antigen exposure and of the disease must be separated and evaluated to make further refinements in commercial production health management programs. Two trials have been conducted to evaluate the impact of immune system activation via antigenic challenge on pig growth.
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