Assessing the pathogens of wild mammals in Los Angeles County

Methods

Summary

Wildlife blood samples (from coyotes, raccoons, skunks, opossums and squirrels) are currently being collected through local collaborations with wildlife and animal control agencies throughout the Los Angeles region. Prior exposure to Leptospira bacteria will be assessed by an external lab at UC Davis using microscopic agglutination testing (MAT), which detects anti-Leptospira serum antibodies that develop following an infection. The results will then be mapped using ArcGIS, using indices of urbanization to gain an understanding of pathogen distribution across this urban landscape. We will summarize all data and share reports with local wildlife, veterinary and public health agencies to inform local officials about disease and transmission potential in these wild mammal populations.

Challenges

It has proven very challenging to obtain skunk carcasses and blood samples, as people tend to discard these animals as quickly as possible (understandably due to their unique odor). There is a possibility that we will not obtain our desired sample sizes for this species, but if this is the case we can test additional samples from other species in order to increase our ability to detect the pathogen those populations. 

Pre Analysis Plan

Once the samples funded here are analyzed for antibodies, the data will then be added to preliminary results to obtain larger samples sizes and a more comprehensive picture of Leptospira bacteria in local wildlife. To assess results along the region's urbanization gradient, I am seeking a minimum total sample size of 30 animals per species from both urban and rural areas (60 total), which would give a 96% probability of detecting at least one infection if the true prevalence of a given pathogen is ≥10%. At the conclusion of the study, seroprevalence levels will be estimated for each species with 95% confidence intervals, and results will be reported to local public health and wildlife agencies.