Further Assessment of Air Filtration for Preventing PRRSV Infection in Large Breeding Pig Herds

February 23, 2011 — 

The filtering of air entering pig housing has been proposed as a means to reduce the risk of airborne transmission of porcine reproductive and respiratory syndrome virus (PRRSV) from infected herds to at-risk populations (Pitkin and others 2009). To test this intervention on a larger scale, a pilot study was recently conducted using 10 treatment herds and 26 control herds over a period of 24 months.

Eight of the treatment herds remained free of infection throughout the study period; two treatment herds experienced clinical PRRS secondary to the introduction of a new variant of the virus from an external source (likely not the result of aerosol transmission). In contrast, 24 of 26 (92 per cent) control herds experienced severe clinical episodes of PRRS secondary to the introduction of new variants of the virus.

Chi-squared analysis indicated that he treatment herds were significantly less likely (P=0.0001) to become infected throughout the 24-month trial period compared with the control herds. In addition, when considering the total number of cases in non-filtered farms with those in filtered farm, it can be concluded that there were seven times fewer outbreaks in filtered farms, a highly significant (P<0.0005) difference. These results support the earlier conclusion that air filtration is an effective means to reduce the risk of external PRRSV introduction to large breeding herds located in regions of high pig density.

S. Dee, G. Spronk, D. Reicks, P. Ruen, J. Deen; Further assessment of air filtration for preventing PRRSV infection in large breeding pig herds; Veterinary Record 2010 167: 976-977. doi: 10.1136/vr.c6788