Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) infections cause significant economic losses to swine producers every year. Aerosols containing infectious PRRSV are an important route of transmission, and proper treatment of air could mitigate the airborne spread of the virus within and between barns. Previous bioaerosol studies focused on the microbiology of PRRSV aerosols; thus, the current study addressed the engineering aspects of virus aerosolization and collection. Specific objectives were to (1) build and test a virus aerosolization system, (2) achieve a uniform and repeatable aerosol generation and collection throughout all replicates, (3) identify and minimize sources of variation, and (4) verify that the collection system (impingers) performed similarly. The system for virus aerosolization was built and tested (Obj. 1). The uniform airflow distribution was confirmed using a physical tracer (<12% relative standard deviation) for all treatments and sound engineering control of flow rates (Obj. 2). Theoretical uncertainty analyses and mass balance calculations showed <3% loss of air mass flow rate between the inlet and outlet (Obj. 3). A comparison of TCID50 values among impinger fluids showed no statistical difference between any two of the three trials (p-value = 0.148, 0.357, 0.846) (Obj. 4). These results showed that the readiness of the system for research on virus aerosolization and treatment (e.g., by ultraviolet light), as well as its potential use for research on other types of airborne pathogens and their mitigation on a laboratory scale.
Highlights
Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically impactful diseases that need to be mitigated to ensure animal production security
We were motivated by the scarcity of research on aerosolized Porcine reproductive and respiratory syndrome virus (PRRSV) and potential limitations of previous data collected without real-time monitoring of an aerosolization system
The Rhodamine B fluorometric data supported the conclusion that the airflow was uniform among the eight treatments (Table 6), i.e., the relative standard deviations (RSD) among all eight treatments was
Summary
Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically impactful diseases that need to be mitigated to ensure animal production security. The disease is caused by a single-stranded RNA virus (PRRSV), initially described by Terpstra et al (1991) and Wensvoort et al (1991). Research suggested that aerosols of infectious PRRSV can travel up to ∼9 km (Dee et al, 2009; Otake et al, 2010). The meteorological conditions that favored long-distance transmission of airborne virus included low temperature, moderate levels of relative humidity, rising barometric pressure, low wind speed, and low sunlight intensity (Dee et al, 2010). It was reported that PRRSV could be infectious for 24 h at 37◦ C (or 99◦F) and survive for 6 days at 21◦C (or 70◦F) (Pitkin et al, 2017). Given its airborne features and survivability, proper treatment of PRRSV aerosols could effectively reduce the transmission of the disease
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