Oral Presentation 64th International Conference of the Wildlife Disease Association 2015

Sarcoptic mange in San Joaquin kit fox: a spatial stochastic model to evaluate control strategies. (#48)

Diego Montecino 1 , Bryan Cypher 2 , Tory Westall 2 , Deana Clifford 3 , Jonna K Mazet 1 , Janet Foley 1
  1. University of California, Davis
  2. California State University, Stanislaus
  3. California Department of Fish and Wildlife, Rancho Cordova

The San Joaquin kit fox (SJKF) (Vulpes macrotis macrotis) is a federally endangered subspecies of kit fox, endemic to California’s southern San Joaquin Valley (SJV). There are now 3 main and a dozen satellite populations remaining after vast habitat destruction. Remarkably, one until-recently stable satellite population is located in the city of Bakersfield, at the southern end of the SJV.

In March 2013 we began to detect fatal cases of sarcoptic mange (SM) in this urban population, the first report of Sarcoptes scabiei in this well-studied species. This ongoing outbreak is a threat for SJKF conservation, as SM morbidity and mortality is high in this naive subspecies (21 SM cases this city, including 12 fatalities and 7 rehabilitated) and SM may expand to surrounding rural areas. SM outbreaks in related naive urban foxes have resulted in over 90% population declines in Europe.

In order to evaluate management strategies to control the current SM outbreak in Bakersfield, we built a spatial stochastic model that iteratively simulated the SJKF population and its annual cycle in this city. We randomly introduced SM in this population and allowed transmission within and among family groups. Population distribution and demography, annual cycling, and disease dynamics were informed by appropriate probability distributions from previous research. By modelling control strategies, we tested the hypothesis that their efficiency depend on the spatial scale and duration of their application, but also on the season of SJKF annual cycle. The objective is to identify the most efficient effort level and time frame to apply control measures in order to reduce/eliminate SM in SJKF in Bakersfield. Results are currently under development and they will support federal and state agencies to manage this disease outbreak in Bakersfield and more broadly.