Survivability of five strains of PRRSV in tap water at different temperatures
Description
Porcine reproductive and respiratory syndrome (PRRS) is considered one of the most economically important diseases of swine, as outbreaks in the U.S. continue occurring despite current rigorous biosecurity measures. Limited information is available regarding the possibility of water contamination and the role of this milieu in dissemination of the PRRS virus. In this study, the survivability of PRRSV in tap water at three temperatures (4°C, 21-23°C, and 37°C) was assessed. Tap water obtained from a laboratory faucet underwent different treatments involving autoclaving and dichlorination. Four strains of PRRSV-2 (L1A 1-7-4, L1C 1-4-4 SD, L9 1-4-2, L5 2-5-2) and one of PRRSV-1 (Lelystad), grown in the MARC-145 cell line ranging from 4 to 5.5 log10 TCID50/0.1 mL, were added to the water samples followed by incubation at different temperatures. At various times, the samples were removed and titrated in cell cultures to determine the amount of viable virus. While there were no major differences between viral strains and water treatments, results showed prolonged survivability (>28 days) of all strains at 4°C, 3 to 7 days at 21-23°C, and <1 day at 37°C. The time required for the virus titer to decrease 99% (T99) further confirmed its longer survivability at lower temperatures, and the comparisons among these results indicate a potential risk of drinking water as a PRRSV carrier in farms, especially at lower temperatures.