E A H Good Health “In Balance” A H Ex: Influenza Agent Increased A H Ex: Tularemia, Plague Host pop. increased
A H A H Ex: Air Pollution -Environment upset & makes host more susceptible Ex: Flood -Environment upset & promotes growth of agent (typhoid fever, cholera)
Diseases & Causative Agents Disease Transmission –Direct: usually within spp. –Indirect: through different spp.
Diseases & Causative Agents Contagious – transmittable to others –All contagious diseases are infectious ContagiousInfectious (not contagious) cold tetanus
Diseases & Causative Agents Chronic: slow-acting to overcome resistance of host (long-term) Acute: short-term, agent overwhelms host rapidly Subclinical: don’t develop clinical signs of disease
Diseases & Causative Agents Pathogenic: ability of agent to induce disease Virulence: severity of disease produced by agent e.g., common cold very pathogenic, not virulent rabies = not very pathogenic, very virulent
Wildlife Diseases Interest from wildlife management point-of- view: –Domestic and/or wild animals can serve as reservoirs and/or vectors –Density of wildlife populations
Wildlife Diseases Interest from human health & safety point- of-view: –Domestic and/or wild animals can serve as reservoirs and/or vectors e.g., avian influenza Since 2003, 393 human cases, 248 deaths (WHO)
Wildlife Diseases Interest from pet/domestic animal health & safety point- of-view: –Domestic and/or wild animals can serve as reservoirs and/or vectors e.g., bovine TB (Mycobacterium bovis)
Wildlife Diseases Interest from wildlife management point-of- view: –Density of wildlife populations –DD response? –Red Grouse & strongylosis (caused by Trichostrongylus tenuis) –Lack’s rebuttal [food supply & weakened state of birds]
Wildlife Diseases Interest from wildlife management point- of-view: –Small populations, threatened/endanger ed spp.
Wildlife Diseases Interest from wildlife management point-of- view: –Small populations, threatened/endangered spp. 1984 Patuxent Wildlife Research Center, 7 of 39 whooping cranes (18% of captive breeding flock) die of possible insect-borne virus
Wildlife Diseases Interest from wildlife management point-of- view: –Part of community dynamics Newfoundland, lynx biting caribou calves, transfer Pasteurella multocida in saliva via bites 27% calf survival before lynx removal 63% calf survival after lynx removal
Wildlife Diseases Wildlife management responses: –Culling Stanislaus Nat’l Forest (CA) , 22,000 mule deer killed in response to foot- and-mouth outbreak in cattle 10% of these showed lesions
Captive and wild cervids –white-tailed deer –mule deer –elk –moose First observed, 1967, Colorado Division of Wildlife’s Research Facility in Fort Collins, CO (initially thought to be malnutrition) 1977 CWD determined to be TSE (mule deer) 1981, 1 st wild animal (elk) from Rocky Mt. Nat’l Park, diagnosed Models suggests may have been present in free-ranging populations of mule deer for more than 40 years
CWD Susceptibility of other cervids to CWD not known Cattle and other domestic livestock appear to be resistant to natural infection (research continues) Privately owned cervid facilities (POC) may allow spread
USDA APHIS WS National Wildlife Research Center (NWRC) Congressional appropriations for research and management of CWD (and many other conflict issues) Dr. Kurt VerCauteren
CWD in WI Discovered wild deer in 2001/2002 >700,000 deer hunters Avg 460,000 deer harvested Generates >$500 million retail ~$1 billion impact to state’s economy
CWD in WI Discovered wild deer in 2001/2002 Spent $40+ million testing and drastically reducing deer populations since Initially planned to kill all estimated 30,000 deer in focal area Saskatchewan spent $30+ million
CWD in WI
Surveillance program to detect 1% prevalence Difference in age/gender –0.16% fawns + –Increase prevalence with age (faster in males) –2-3% yearlings + –2+ yrs (M = 10%, F = 4-5% +)
CWD in Michigan Michigan : Michigan's First Case of Chronic Wasting Disease Detected at Kent County Deer Breeding Facility Date: August 25, 2008 Source: Michigan Department of Natural Resources LANSING - The Michigan departments of Agriculture (MDA) and Natural Resources (DNR) today confirmed the state's first case of Chronic Wasting Disease (CWD) in a three-year old white-tailed deer from a privately owned cervid (POC) facility in Kent County. The state has quarantined all POC facilities, prohibiting the movement of all - dead or alive - privately-owned deer, elk or moose. Officials do not yet know how the deer may have contracted the disease. To date, there is no evidence that CWD presents a risk to humans.
CWD in Michigan Michigan : Tests of More Than 1,000 Deer Find No More Cases of Chronic Wasting Disease Date: October 07, 2008 Source: The Grand Rapids Press Statewide, 1,095 deer have been tested, with 964 testing clean and 131 awaiting results. More than 300 wild Kent County deer have been tested and found to be clear of chronic wasting disease after the highly contagious disorder was found in one northern Kent County farm- raised deer in August. Approximately $1 million spent on testing