Data from: Previous exposure to myxomatosis reduces survival of European rabbits during outbreaks of rabbit haemorrhagic disease

1. Exploiting disease and parasite synergies could increase the efficacy
of biological control of invasive species. In Australia, two viruses were
introduced to control European rabbits Oryctolagus cuniculus — myxoma
virus in 1950, and rabbit haemorrhagic disease virus in 1995. While these
biological controls caused initial declines of > 95% in affected
populations, today rabbits remain a problem in many areas, despite
recurring outbreaks of both diseases. 2. We used eighteen years of
capture-mark-recapture, dead recovery, and antibody assay data from a
sentinel population in South Australia to test whether these two diseases
interact to modify the survival of individual wild rabbits. We compared
four joint, multi-state, dead-recovery models to test the hypotheses that
rabbit haemorrhagic disease and myxoma viruses have synergistic (i.e.,
previous exposure to one virus affects survival during outbreaks of the
other virus) or additive effects (i.e., previous exposure to one virus
does not affect survival during outbreaks of the other virus). 3. Rabbit
haemorrhagic disease outbreaks reduced the survival of individuals with no
immunity by more than half during the 58-day capture-trip intervals, i.e.,
from 0.86–0.90 to 0.37–0.48. Myxomatosis outbreaks had a smaller effect,
reducing survival to 0.74– 0.82; however, myxomatosis outbreaks were more
prolonged, spanning more than twice as many trips. 4. There was
considerable information-theoretic support (wAICc = 0.69) for the model in
which exposure to myxomatosis affected survival during rabbit haemorrhagic
disease outbreaks. Rabbits previously exposed to myxoma virus had lower
survival during rabbit haemorrhagic disease outbreaks than rabbits never
exposed to either virus. There was negligible support for the model in
which previous exposure to rabbit haemorrhagic disease affected survival
in myxomatosis outbreaks (wAICc < 0.01). 5. Synthesis and
applications — Our results indicate that biological control agents can
have a greater impact than single-pathogen challenge studies might
suggest. Introducing additional biological control agents might therefore
increase mortality of rabbits beyond the additive effects of individual
biological controls. Furthermore, our results show that by understanding
and exploiting disease synergies, managers could increase the efficacy of
biological controls for other invasive animals.