The effect of immunes on the spread of distemper in small ferret populations

Abstract

The rate of distemper virus ( DV)-immune ferrets in inhibiting the spread of DV in small closed populations of individually caged ferrets was studied. A random walk epidemic simulation and a “Poisson” epidemic simulation were used in conjunction with actual experimental outbreaks. The results of the simulation and the experimental outbreaks are in agreement. After the DV became established in a totally susceptible population, vaccination of 50–90% of the survivors failed to stop the outbreak. Conversely, it is difficult to start an outbreak if 70% or more of the population is immune at the time DV is introduced.