Brushtail possum (Trichosurus vulpecula) social interactions and their implications for bovine tuberculosis epidemiology

Abstract

The brushtail possum is the main reservoir of bovine tuberculosis in New Zealand. Disease prevalence is generally higher in males than in females. This has conventionally been assumed due to greater infection rates of males, but recent work has raised the hypothesis that it may instead be driven by survival differences. With bovine tuberculosis transmission among possums most likely occurring between individuals in close proximity, here we analyse social networks built on data from wild possums collared with contact loggers inhabiting a native New Zealand forest, to investigate whether there is mechanistic support for higher male infection rates. Our results revealed that adult female possums were generally just as connected with adult male possums as other adult males are, with male-female connection patterns not being significantly different. This result suggest that the new 'survivorship' hypothesis for the sex bias is more likely than the conventional 'infection rate' hypothesis. © 2018 Copyright 2018 by Koninklijke Brill NV, Leiden, The Netherlands