CWD in Wild Herds
While APHIS' primary focus is on farmed animals, we have been concerned about protecting the health of wild animals as well. Because the health of wild cervids can impact the alternative livestock industry and vice versa, APHIS had assisted States with CWD surveillance in wild animals from 1997 through 2011. State wildlife management agencies and in some cases, Federal Land Management agencies, have regulatory authority over wild cervids and, as such, take the lead in decisions regarding surveillance of the animals under their stewardship.
Summary of Nationwide Chronic Wasting Disease Testing in Wild Cervids:
From 1998 -2011, APHIS directly assisted States in CWD surveillance testing of free-ranging cervid populations In addition to assisting individual States to determine whether or not CWD was present in their wild populations, the information collected in this effort also provided a better idea of the national distribution of CWD in wild cervid populations.
Initially, the majority of the states conducted routine surveillance in a statewide design, but as our knowledge increased about transmission and routes of exposure of CWD in cervids, more states began to target their testing in areas with known or suspected CWD risk factors, which may include some or all of the following: areas with CWD-positive farmed herds, areas adjacent to CWD-positive wildlife, areas adjacent to land on which CWD-positive animals have lived (farmed or wild), areas with high concentrations of farmed or captive cervids and areas permitting transport of hunter-killed cervid carcasses from CWD infected areas. Another type of targeted surveillance occurs when deer or elk that show suspected clinical signs of CWD are reported with samples collected and submitted for testing. In general most surveillance plans sought to detect disease between 0.1% - 5% prevalence with confidence intervals between 95% and 99%.
This type of sampling takes place throughout the year. Refer to links to State wildlife agencies for further information on their surveillance efforts. By 2011, 16 States reported CWD positive findings in their wild cervid populations. View a graph of the annual totals of CWD surveillance in free-ranging cervids and a map of States that have identified CWD in their free-ranging wild cervid populations.
Last Modified: June 20, 2012