In the midst of the sixth mass extinction, understanding wildlife disease spillover
is critical to maintaining protected wildlife areas. Studying ecoimmunology and wildlife
disease ecology helps to understand immune and disease traits in an ecological context,
which is invaluable in preventing pathogen spillover between livestock and wildlife. To
investigate this interface, tests of innate immunity were validated in various ungulates
and desert bighorn sheep, and then infectious spillover diseases in desert bighorn sheep
and African buffalo were examined. In ungulates at Wildlife Safari in Oregon, innate
immunity varied between species and strong positive correlations were found between
innate immunity measures. In general, ecoimmunology study results are robust to the
choice of innate immune defense assay. In desert bighorn sheep in California, an ELISA
was developed that could measure natural antibody levels from blood samples, and
differences in natural antibody levels and a bacterial killing assay were found between
Peninsular and Mojave desert bighorn sheep. Spillover of Mycoplasma ovipneumoniae
from domestic animals to desert bighorn sheep can lead to region-wide extinction.
Disease prevalence, connectivity, genetic data, and immunophenotype were utilized to show that better connected populations resisted pathogen invasion. Finally, in Kruger National Park, South Africa, African buffalo calves infected with foot-and-mouth disease virus reinfected previously exposed animals to become carriers. Other risk factors for carrier status were identified: low body condition score, younger age, and being male. Identifying these attributes during risk assessment of stray buffalo could be used to help avoid foot-and-mouth disease spillover to cattle on the park border.