Impulse Vaccination Model for the Control of Devil Facial Tumor Disease

Devil facial tumor disease (DFTD) is a cancer that affects Tasmanian devils and that has caused the devil population to grossly decline since 1996. We present an SEIVR model to explore if recent advances in DFTD vaccines can help the wild population recover. Considering both and bi-annual impulse of vaccinating wild devils through food drops and introducing vaccinated captive-bred devils into the population, we explore the vaccine efficacy, percent of healthy devils receiving the vaccine, and years of campaign necessary for the devil population to have a long-term recovery. Based on our initial parameter estimations, we find a stable population can be reached after 8 years of bi-annual bait drop vaccine campaigns and introduction of 2 captive-bred vaccinated devils into the wild population. Additionally, we find a 14% maximum vaccine failure rate and 60% minimum vaccine bait ingestion by wild devils is necessary for a successful 10-year campaign.