Ranaviruses infect fish, amphibians, and reptiles. The present study was conducted to compare the persistence of amphibian and reptilian ranaviruses in a pond habitat. The 4 viruses used in this study included 2 amphibian ranaviruses, Frog virus 3 (FV3, the type species of the genus Ranavirus) and an isolate from a frog, and 2 ranaviruses of reptilian origin (from a tortoise and from a gecko). A sandwich germ-carrier technique was used to study the persistence of these viruses in sterile and unsterile pond water (PW) and soil obtained from the bank of a pond. For each virus, virus-loaded carriers were placed in each of the 3 substrates, incubated at 4 and 20°C, and titrated at regular intervals. Serial data were analyzed using a linear regression model to calculate T-90 values (time required for 90% reduction in the virus titer). Resistance of the viruses to drying was also studied. All 4 viruses were resistant to drying. At 20°C, T-90 values of the viruses were 22 to 31 d in sterile PW and 22 to 34 d in unsterile PW. Inactivation of all 4 viruses in soil at this temperature appeared to be non-linear. T-90 values at 4°C were 102 to 182 d in sterile PW, 58 to 72 d in unsterile PW, and 30 to 48 d in soil. Viral persistence was highest in the sterile PW, followed by the unsterile PW, and was lowest in soil. There were no significant differences in the survival times between the amphibian and reptilian viruses. The results of the present study suggest that ranaviruses can survive for long periods of time in pond habitats at low temperatures. KEY WORDS: Ranaviruses · Pond water · Persistence · Soil Resale or republication not permitted without written consent of the publisherDis Aquat Org 98: [177][178][179][180][181][182][183][184] 2012 transmitted to healthy salamanders after putting them in the water where infected salamanders were previously kept, even after passing the water through 0.45 µm pore size filters. In one transmission study, it has been observed that salamanders acquired infection after water-bath exposure to ATVcontaminated water and also transferred the infection to other healthy individuals (Brunner et al. 2007). The exposure of Rana sylvatica tadpoles to sediments collected from a pond where a ranavirus die-off had occurred resulted in the development of infection in the exposed individuals (Harp & Petranka 2006). Similarly, experimentally inoculated moist sediments also transmitted ATV infection and caused mortality in larval salamanders (Brunner et al. 2007). These studies indicate that in a small pond habitat, contaminated water and soil can be a potential source of virus transmission to susceptible animals.There is scarcity of data on the environmental persistence of iridoviruses infecting reptiles and amphibians. One report shows that the infectivity of ATV-contaminated water was lost after a 2 wk incubation at 25°C (Jancovich et al. 1997). Langdon (1989) observed that a fish ranavirus, closely related to amphibian ranaviruses, can survive for 97 d in water at 15°C. A comparison ...