The effect of manipulating population density on the probability of den-sharing among common brushtail possums, and the implications for transmission of bovine tuberculosis

In: Wildlife research, Volume 25, Issue 4, p. 383

Abstract

Common brushtail possums (Trichosurus vulpecula) act as
a reservoir of bovine tuberculosis (Mycobacterium bovis)
in New Zealand and the simultaneous sharing of dens may result in the
transmission of Tb between possums. The effect of manipulating population
density on the per capita probability of simultaneous
den-sharing among possums was investigated at a site near Dunedin, New
Zealand. Den characteristics that could affect the probability of simultaneous
sharing were also investigated, though none were found to be significant. The
daily probability of a possum sharing a den was estimated to be 0.07 for
possums denning within uncontrolled areas of the study area. Den-sharing was
most common between female pairs, though sharing was also recorded between
male–female and male–male pairs. The highest number of possums
recorded sharing a single den was four. Reducing population density
significantly lowered the probability of possums simultaneously sharing dens
within the study area, with greater than 60% reductions estimated to
eliminate simultaneous den-sharing altogether. The relationship between the
contact rate arising from den-sharing and population density was convex-down,
rather than convex-up, as often hypothesised for animal–animal disease
contact processes. The implications of simultaneous den-sharing for the
transmission and control of bovine tuberculosis in brushtail possum
populations are discussed.