Adding to the existing pressures of habitat loss, poaching and depletion of prey species, a new threat to tiger populations in the wild has surfaced in the form of a deadly virus.
According to a new study from the Wildlife Conservation Society (WCS), canine distemper virus (CDV) has the potential to be a significant driver in pushing the tigers towards extinction.
While CDV has recently been shown to lead to the deaths of individual tigers, its long-term impacts on tiger populations had never before been studied, researchers said.
The authors evaluated these impacts on the Amur tiger population in Russia's Sikhote-Alin Biosphere Zapovednik (SABZ), where tiger numbers declined from 38 individuals to 9 in the years 2007 to 2012.
In 2009 and 2010, six adult tigers died or disappeared from the reserve, and CDV was confirmed in two dead tigers leading scientists to believe that CDV likely played a role in the overall decline of the population.
Joint investigations of CDV have been an ongoing focus of scientists since its first appearance in tigers in 2003.
The finding shows that smaller populations of tigers were more vulnerable to extinction by CDV . Populations consisting of 25 individuals were 1.65 times more likely to decline in the next 50 years when CDV was present.
The results are profoundly disturbing for global wild tigers given that in most sites where wild tigers persist they are limited to populations of less than 25 adult breeding individuals.