Comparison of Virus Survival in Freshwater Sources

Enteric viruses are a potential cause of human gastroenteritis. Their ability to cause waterborne disease may be attributed to their low infectious dose and survival for prolonged periods of time in aquatic environments. Virus survival studies have shown temperature to be a major factor in determination of inactivation rates. Literature on virus inactivation rates at various temperatures was compiled for freshwater sources including ground, tap, river, and impounded water. Data were grouped according to either virus type or water source. Linear regression and analysis of variance were used to evaluate the significance of temperature on virus survival. Data were also analyzed to obtain a general line of best fit for virus inactivation at various temperatures. Temperature was found to be a significant factor in virus inactivation. However, significance of the effect of temperature varied with virus type and water source. Approximately 3 to 99% of variation in virus inactivation rates can be explained by temperature. The slowest inactivation rate obtained was for coliphage in ground water. Inactivation rates for virus in tap water were among the highest and the overall mean inactivation rate for all virus data was slightly greater than 0.5 log per day. Future comparisons of the effect of temperature as well as other environmental factors on virus survival may require the development of standard methods for virus inactivation studies.