CategorySwine Health - General Disease
Date Full Report Received03/31/2015
Date Abstract Report Received03/31/2015
Funded ByPork Checkoff
It is important to study survival of viruses in environmental samples (feces, slurry, water, and feed) to determine the risk posed by indirect routes of transmission. The results of such studies can help design effective control strategies against viral infections. Many factors can influence virus survival in the environment including temperature, relative humidity (RH), desiccation, ultraviolet light, the milieu in which the virus is suspended, and physicochemical properties of the virus. This study was designed to determine the survival of porcine delta coronavirus (PDCoV). The procedures used were similar to those used in a recently completed study on environmental stability of porcine epidemic diarrhea virus (PEDV) (NPB-13-215). The results of this study indicate that PDCoV survives for a long period of time (>21 days) in various samples analyzed and that it is often difficult to inactivate it completely. As with other viruses, the PDCoV is killed at a faster rate at 60°C than at 40oC or 50oC. In addition, we measured the effect of storage conditions on the inactivation of PDCoV in feces, slurry, drinking water, recycled water, feed, and feed ingredients. In feces, it took 28 days for inactivating 99.9% of the virus but it took 42 days to completely inactivate the virus at 60°C regardless of the relative humidity (RH)(30%, 50%, or 70%). The results of storing feces at 50oC (at 50% and 70% RH) and at 60°C (at 70% RH) were essentially similar. Interestingly, the effects of temperature and RH on survival of virus in slurry were also similar. When slurry was stored at room temperature (25oC), 99.99% of the virus was killed within 49 days. In drinking water, 99.9% of the virus was killed within 35 days. In meat meal, corn, low oil DDGS, and medium oil DDGS, it took 21 days 4 log10 (99.99%) reduction in PDCoV. In conclusion, PDCoV survives for extended periods of time in feces, feed, and feed ingredients. This prolonged survival can be reduced by heat. Further research is indicated to determine the comparative survival of swine enteric coronaviruses in the environment so that effective control strategies can be designed and implemented.