Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/30/2015
Publication Date: 5/1/2015
Publication URL: http://www.tandfonline.com/doi/pdf/10.1080/19336896.2015.1033248
Citation: Silva, C.J., Erickson-Beltran, M.L. 2015. The view from above: The potential of aerial surveillance in identifying CWD infected herds.. Meeting Abstract. Prion (Supplement 1) 9: S73..
Interpretive Summary: Other researchers examined satellite images of domestic cattle and noted that they appeared to align their bodies with the magnetic North Pole. Chronic wasting disease (CWD) is a transmissible disease found in deer, elk, and moose. It causes behavioral changes before the animals eventually die. These changes may be visible as misaligned animals within an infected herd. We examined aerial surveillance images from Tomales Point California, the site of a tule elk preserve where the animals freely roam over a 2600 acre site. When we examined the alignment of the elk, we saw that they did not align in any observable manner. This indicates that misalignment of animals is not a useful means of inferring the presence of CWD in a herd. Instead, using aerial surveillance to estimate the number of fawns associated with a doe may be a useful way of inferring the presence of CWD in a herd. As aerial surveillance becomes cheaper, more detailed, and widely available, it may be useful in determining the levels of CWD infectivity in a wild population.
Technical Abstract: Background/Introduction. Large mammals such as domestic cattle and red deer have been reported to align themselves with the magnetic North Pole. Since chronic wasting disease (CWD) affects the behavior of infected cervids, it may be possible to estimate the infection rate, at a herd level, by determining the changes in the alignment of the animals with respect to the magnetic pole. Using available aerial surveillance data from California, a CWD-free state, the alignment of a free ranging elk was determined. Materials and Methods. Tomales Point is a 2,600 acre fenced-in preserve inside the Point Reyes National seashore. It consists of open grassland and coastal scrub where native California tule elk (Cervus canadensis nannodes) roam freely. These elk were introduced to the preserve in 1978 and are part of a program to rebuild the tule elk population in California. There are no other large mammals inside the fence. The aerial surveillance data was examined and approximately 146 elk were identified and their orientation determined. Results and Conclusions. Analysis of the alignment data demonstrated that tule elk show no particular alignment in any direction. Further research will need to be performed to determine if CWD infected animals have a greater tendency to align themselves with the magnetic pole. As the cost of high-resolution images decreases and aerial surveillance data becomes more available, it may be possible to use other parameters, such as fawn count per doe to estimate CWD prevalence in an infected herd.