ANSC 100

because bats with the disease poop in the pig barn and pigs get contact though fecal or aeresol contamination

mainly through wild bird movement

• ^{"organisms whose known characteristics can be measured to asses the extent of enviro implications and to provide early warning of thos implicattions"}
• -provide early warning of human health hazards in the enviro

• lyme disease in North America (sentinel =dogs)
• Minimata Disease (methyl mercury poisoning) Japan (sentinel =cats, seawee, seabirds, wildlife)

• "Canaries in the coal mine"
• canaries taken into coal mine to warn of noxious gases
• more sensitive to odourless coal gas than humans (air monitors)

• borrelia burgdorfei
• vector is Ixodes ticks (not common in AB)
• Primary hosts: mice, squirrels, other mammals, small birds, migratory birds
• Tick infected by biting into the rodent, then later tick stage bites larger animal- dog, cat, deer, human
• the pathogen is transmitted when the tick's mouthparts are attached for 18-24 hours (this time b4 transmits disease)
• spread originally from eastern US, across midwest pacific states
• not yet thought to be endemic in AB
• surveillance program in AB since 2007--> submit ticks to vets--> AB ag parasitology (some ticks submitted where infected)
• symptoms (humans): fever, headache, fatigue, swollen lymph nodes, arthritis
• "bulls-eye rash"
• symptoms (dogs): fever, lethargy, shifting arthritis
• Diagnosis: blood testing (for antibodies)
• treatment: antibiotics

• japan
• 1956, in minimata, the first patient was reported initially as suffering from nervous symptoms: unknown cause
• 1965 patients reported in agano river basin
• research on the cause:
• initially suspected: viral encephalitis then a food poisoning
• fish and shellfish mediated food poisoning was first suspected
• then chem intoxication suspected in food contamination/poisoning
• men and women of all ages but not infants
• later children were born with congenital neurologic defects (severe brain injusry ie couldnt walk)
• anecdotal evidence:
• cats in victim's families often showed similar strange behaviour
• 1950s and onwards cats had been seen to have convulsions, go mad and die. locals called it the "cat dancing disease"
• wildlife in the surrounding area were also affected months or years prior to the outbreak in humans
• crows had fallen from the sky, seaweed no longer grew in the sea bed and fish floated dead on the surface sea
• The staple food of residents and their pets was seafood
• thus fish and shellfish mediated food poisoning was first suspected BUT
• research considered geographical and chronological distribution of victims and suspected a chem substance contained in teh waste discharge from an acetaldehyde plant loacted in the shores on minimata bay
• mercury was confirmed several years later
• mercury poisoning in shell fish
• ending the contamination, cleanup, and compensation of victims took years
• gov official conclusion of the cause 1968 (12 yrs later)
• march 2001 2265 victims officially recognized. over 100000 had recieved financial compensation from the company. and lawsuits continue today

• loss or modification of habitat
• prediction (ecological changes affecting predators or prey)
• intro of non-native species
• air and water quality impacts
• climate changes

• herbicides
• pesticides
• heavy metals ie led toxicity
• other materials in run offs
• decreased pH and increased salinity
• lowering water tables
• loss of freshwater spring flows: changed quality and quantity

• greenhouse fas production
• volatile organic compounds
• aerosolized pesticides and other chemicals
• particulate matter and silt/sedimentation

• habitat modification and or destruction
• predation- intro non native competitors
• volatile organic compounds/ skin, eggs, tads
• air and water born chemicals, heavy metals
• acid rain and increased UVB exposure
• retinoids such as retinoic acid
• climate change and emerging diseases
• trematodes
• fungi such as chytrid
• iridescent virus such as iridovirus (ATV)
• probably not a single cause but many causes together. are frogs therefore a sentinel species?

• human epidemiological studies
• advantages: relevant species and exposure (no extrapolations)
• disadvantages: insentiv, long latency, confounding variables ie expensive, complex exposures, no experimental datat
• laboratory Animal Toxicological studies
• advantages: homogenous population controlled conditions and short exposure times
• disadvantages: homogeneous population, high to low dose extrapolation, animal welfare issues

• 1. Descriptive Epidemiology
• characterize the frequency and patterns of disease in animal populations and ID possible associations with enviro exposures. (how many exposed, how many got the disease, what happened)
• 2. Analytic epidemiology
• test hypotheses of enviro exposure-disease relationships in animals using controlled-observational methods
• 3. In situ studies
• placement of sentinel animals at a site where enviro contamination is suspected (animals are monitored under controlled conditions to asses any health affects)
• have long been used to test for the presence of certain infectious organisms in the enviro
• ie sentinel chickens are stratigically placed and monitored by regular blood tests for the development of antibodies t0 viruses that cuase encephalitis to ppl (WEE, EEW: western and eastern equine encephalitis)
• detection of such antibodies prompts immediate mosquito control measures and public health education efforts

exposed to chemical contaminants in habitat shared with human or comparable with human habitats and similar concentrations (ideally same habitat as us)

• *Asbestos and mesothelioma* (be able to spell)
• mesothelioma is a highly fatal cancer of humans and dogs caused by asbestos exposure
• latency period between exposure and disease may be >25 yrs in  humand vs <8 years in dogs
• pet dogs with spontaneous mesothelioma were used to ID enviro exposures taht might increase their ownders risk of asbestos related diseases
• dogs shared owners enviro and may come in contact with fibers brought home on clothing but dont have other occupational exposures that could confound interpretation of human epedemiological studies
• lung tissues from 3 dogs with mesothelioma and 1 with squamous cell carcinoma of teh lung had significantly higher concentrations of of asbestos fiber than lung tissue of age matched control dogs that died of non pulmonary related causes
• findings confirmed that asbestos exposure is a risk factor for mesothelioma in the dog as it is in humans
• vets should therfor report any dog with mesothelioma to their local health department --> efforts could be made to ID the source of asbestos in these households and to screen household members for early radiographic signs of asbesots-related disease

• pet animals can serve as valuable sentinels for hazards in the home enviro
• diseases of animals only make useful sentinels if they are recognized and reported in a timely manner
• sentinel systems require cooperation between human and vet health specialists