Tasmanian devils are passing their infectious cancer on to a smaller number of other devils, Science reports.
It adds that devil facial tumor disease (DFTD) had been spreading exponentially among Tasmanian devils, leading researchers to worry that they could go extinct, but a new study indicates that the pace of disease spread has slowed. An international team of researchers conducted a phylodynamics analysis of the disease based on about two dozen genes in the DFTD genome that act as clock-like markers.
As they report in the journal Science, the researchers found that the rate at which the disease spreads has fallen. Shortly after DFTD was uncovered, an infected devil infected about 3.5 other devils, but now an infected devil infects about one other.
First author Austin Patton, who was at Washington State University, Pullman, and now is at University of California, Berkeley, tells Science that the slower disease spread could be due to the decline in the density of Tasmanian devils, though he notes, though, that the remaining devils could have stronger immune systems or adopted different behaviors.
Another study out this week in the Proceedings of the Royal Society B supports the notion that behavior can affect spread, Science adds, as it found even usually aggressive devils interacted less with others after becoming infected.