Course of an Isolated Ranavirus Outbreak in a Pelobates fuscus Population in The Netherlands

Viruses in the genus Ranavirus (family Iridoviridae) are known to have the potential to adversely
affect fish, amphibians, and reptiles. Ranaviruses are associated with large-scale die-offs and rapid population declines in amphibians. The development and progression of an outbreak, however, vary greatly depending on the host species and geographic location. We describe the recurrent course of an outbreak of common midwife toad virus in an isolated population (Staphorst) of common spadefoot toads (Pelobates fuscus) in The Netherlands from 2012 to 2015. After initial mass mortality of toad larvae in 2012, no mass mortality was recorded in 2013 and 2014. In 2015, however, a recurrent outbreak of the virus is believed to have caused high mortality rates among this species in the Staphorst population.