Assessment of area spread of porcine reproductive and respiratory syndrome (PRRS) virus in three clusters of swine farms

Abstract

Despite decades of porcine reproductive and respiratory syndrome (PRRS) research, outbreaks with emerging and re-emerging PRRS virus (PRRSV) strains are not uncommon in North America. The role of area spread, commonly referred but not limited to airborne transmission, in originating such outbreaks is currently unknown. The main objective of this study was to explore the role of area spread on the occurrence of new PRRSV cases by combining information on genetic similarity among recovered PRRSV isolate's open-reading frame (ORF) 5 sequences and publicly available weather data. Three small regions were enrolled in the study for which high farm-level participation rate was achieved, and swine sites within those regions were readily sampled after reporting of an outbreak in a sow farm. Oral fluid PCR testing was used to determine PRRSV status of farms, and wind roses were generated for assessment of prevailing wind directions during 2-14 days preceding the outbreak. Under the conditions of this study, the data did not support the area spread theory as the main cause for these outbreaks. We suggest that for future studies, analysis of animal movement and other links between farms such as personnel, equipment and sharing of service providers should be incorporated for better insights on source of the virus. Furthermore, the development of rapid and easy diagnostic methods for ruling out resident PRRSV is urgently needed.

Porcine reproductive and respiratory syndrome virus dissemination across pig production systems in the United States

“…Airborne spread has been suggested as a potential route (Dee, Otake, Oliveira, & Deen, 2009;Otake, Dee, Corzo, Oliveira, & Deen, 2010). However, Arruda et al (2018), Arruda et al (2019) did not reach that same conclusion. Pig farm density as expected arises as a risk factor in several studies and in our study, our phylodynamic findings agree with a regional spread as an important factor for PRRSV dissemination among pig farms.…”

Aerosol Detection and Transmission of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV): What Is the Evidence, and What Are the Knowledge Gaps?

“…Recently, Arruda et al [53] published one of the few prospective case studies involving field data that aimed at investigating the role of area spread in PRRSV transmission in swine dense regions in the U.S.; including the swine dense regions of North Carolina and Iowa. The authors took advantage of three naturally occurring sow farm PRRSV outbreaks to sample surrounding farms and check whether the virus identified on the focus outbreak farm could be found in neighboring farms.…”

Autophagy Involved in Antiviral Activity of Sodium Tanshinone IIA Sulfonate against Porcine Reproductive and Respiratory Syndrome virus Infection in vitro

“…Porcine reproductive and respiratory syndrome virus (PRRSV), a member of Nidovirales within the Arteriviridae, is a single-stranded RNA virus causing severe reproductive failure, respiratory distress, high morbidity and mortality in pigs [1,2]. Although vaccination is a common immune method that plays an important role in controlling the disease process, still many problems exist, such as improper immune effect, virus variation and strengthened virulence [3][4][5][6].…”