Chronic Wasting Disease Research at
the USGS-Wisconsin Cooperative Wildlife Research Unit
Potential
for Interspecies Transmission of Chronic Wasting Disease: Assessment of Carcass
Decomposition and Identification and Testing of Potentially Affected Species
Principle Investigator: Dr. Michael Samuel
USGS
Research Associate: Dr. Chris Jennelle
Student: Cherrie A. Nolden
Background
Recent studies indicate that
chronic wasting disease (CWD)
may be transmitted to deer by direct contact, from fecal or urine
contamination, or through environmental contamination associated with carcasses
of infected deer. The potential for environmental contamination with CWD
provides a potential source for transmission to wildlife that share habitat
with white-tailed deer. Carcasses of deer will also be consumed by wildlife,
but little is known about the frequency and range of species that eat deer
carrion and could be exposed to CWD from an infected carcass. In Wisconsin, the
primary carrion consumers will likely include Eastern coyote (Canis
latrans), red fox (Vulpes
vulpes), common raccoon (Procyon
lotor), striped skunk (Mephitis
mephitis) and Virginia opossum (Didelphis
virginiana). Although these species may consume infected
deer tissue, it is unknown whether CWD can successfully cross the species
barrier to infect these animals.
Objectives
This research is intended
to:
investigate the decomposition of deer carcasses
determine the types and number of animals that
consume deer carcasses
evaluate the possibility of interspecies transmission
of CWD from white-tailed deer (Odocoileus
virginianus) carcasses to carrion consumers.
Methods
We will identify the species
that consume deer carrion, as they are the most likely to encounter PrPCWD
from a deer that died of the disease, by using remotely triggered cameras
on deer carcasses (fawns or adults testing negative by immunohistochemistry [IHC]) throughout the
CWD-affected region of Wisconsin.
We are collecting up to 100 of each primary carrion consumer species annually from
the CWD-affected
region of southern Wisconsin, with the assistance of the Wisconsin Trappers Association. Collected
animals will be necropsied to collect brain, lymph node, spleen and feces,
which will be tested for the resistant form of the prion protein that causes
CWD.
The native species that we are collecting from the
CWD-affected region of southern
Dr. Dorothy Ginnett
at the University of Wisconsin-Stevens Point
is evaluating heartworm (Dirofilaria
immitis) in the canids.
Dr. Shelly Michalski at the
University of
Wisconsin-Oshkosh is evaluating tissues and serum for Neospora
caninum.
Dr. Doug Docherty
and Dr. Hon Ip
at the National Wildlife Health Center
are evaluating samples for WNV antibody.
Dr. Jennifer
Meece and Dr. Kurt
Reed at Marshfield Clinic
Research Foundation are doing the majority of the diagnostic testing:
Eastern
equine encephalitis virus (EEE),
LaCrosse encephalitis
virus (LAC),
Western
equine encephalitis virus (WEE),
St.
Louis encephalitis virus (SLE),
Lyme
disease (Borrelia burgdorferi),
Ehrlichia species,
Bartonella species,
Mycobacterium bovis and M.
avium paratuberculosis,
Echinococcus
multilocularis and E. granulosus
Species Observed Near or Consuming Deer Carcasses:
(Click on links to view images from the study)
Mammals
Virginia Opossum (Didelphis virginiana)
Common Raccoon (Procyon lotor)
Striped Skunk (Mephitis mephitis)
White-footed Mouse (Peromyscus leucopus)
Domestic Dog (Canis
familiaris)
Domestic Cat (Felis sylvestris catus)
Eastern Coyote (Canis latrans)
Red Fox (Vulpes vulpes)
Grey Fox (Urocyon
cinereoargenteus)
Eastern Grey Squirrel (Sciurus carolinensis)
Eastern Cottontail (Sylvilagus floridanus)
White-tailed Deer (Odocoileus
virginianus)
Mink (Mustela vision)
River Otter (Lutra canadensis)
Northern Short-tailed Shrew (Blarina
brevicauda)
Southern Flying Squirrel (Glaucomys volans)
Woodchuck (Marmota monax)
Ermine (Mustela erminea)
Birds
American Crow (Corvus brachyrhynchos)
Red-tailed Hawk (Buteo jamaicensis)
Rough-legged Hawk (Buteo lagopus)
Black-capped Chickadee (Poecile atricapillus)
Hairy Woodpecker (Picoides villosus)
Turkey Vulture (Cathartes aura)
Golden Eagle (Aquila
chrysaetos)
Great Horned Owl (Bubo
virginianus)
Bald Eagle (Haliaeetus
leucocephalus)
Barred Owl (Strix varia)
Blue Jay (Cyanocitta
cristata)
Downy Woodpecker (Picoides
pubescens)
Dark-eyed Junco (Junco
hymenalis)
Northern Flicker (Colaptes
auratus)
White-breasted Nuthatch (Sitta
carolinensis)
Ring-necked Pheasant (Phasianus
colchicus)
Red-bellied Woodpecker (Melanerpes carolinus)
American Robin (Turdus
migratorius)
Tree Swallow (Tachycineta
bicolor)
Tufted Titmouse (Baeolophus
bicolor)
Wild Turkey (Meleagris
gallopavo)
Video clips of scavengers at the carcasses (click on
picture to view clip)
Cat
Dog
Skunk & Opossum Peromyscus
Preliminary
Results
Short Summary
- Deer carcasses placed on the landscape
disappeared in about 30-50 days and there were no significant differences
among habitats or study years
- Raccoons, opossums, skunks, coyotes, dogs and Peromyscus
were the most active mammals at deer carcasses
- Crows were the dominant species feeding on deer
carcasses. Turkey vultures and Red-tailed hawks were also frequent
scavengers of deer carrion
- Deer were rare visitors of carcasses and none
were observed consuming tissues
Preliminary Conclusions
Deer carcasses are present
on the landscape for at least 30-40 days. During that time they are
consumed by many of the common avian and mammalian scavengers. The
mammalian scavengers may be exposed to the infected tissue of deer that die
from CWD and are thus at potential risk of infection. The avian species
are not susceptible to TSE diseases, but could play a role in transporting CWD
prions from infected deer to the environment.
Page
created by Cherrie Nolden
Last
Updated: 03/06/06