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  1. Climate change and zoonotic diseases OEMAC Oct 5, 2010 Emily Jenkins, PhD, DVM, BSc University of Saskatchewan

  2. Learning objectives • Have an understanding of the mechanisms by which climate change may alter the ecology of zoonotic diseases • Identify zoonoses that may be influenced by climate change in Canada • Identify vulnerabilities and ways to predict and mitigate the effects of climate change on diseases of public health significance

  3. Is the global climate really changing? • 11 of the last 12 years are among the 12 warmest since 1850 • Linear rate of warming in last 50 years is double the centennial rate • Present sedimentary levels of methane and carbon dioxide are unprecedented in the last million years “The present situation has no analogue.” Delecluse 2008, OIE Revue Scientifique et Technique

  4. Regional warming 1948-2008 1.6 C 2.0 C 2.1 C 1.7 C 1.5 C 1.4 C

  5. Annual precipitation departures from normal (Environment Canada, 1948-2009) % Year

  6. Overall: warmer, wetter, and more extreme

  7. Western Arctic 2020’s Each symbol represents a projection from a Global Climate Model using a given Emissions Scenario 2050’s Precipitation Change (%) Furgal and Prowse, 2007 2080’s Mean Temperature Change (C)

  8. Scenario storylines: socioeconomic drivers of climate change

  9. 2-4 C 4-6 C 6-8 C Furgal & Prowse,2007

  10. 5-8% 5-15% 15-30% Furgal and Prowse, 2007

  11. Climate change in Canada (Adapted from Rizzo, B. and E. Wiken.1992. Assessing the Sensitivity of Canada's Ecosystems to Climate Change. Climate Change 21: 37-55.)

  12. Effects of climate change on disease • Development and survival of pathogens in • the environment • cold-blooded hosts and vectors • Distribution and abundance of hosts • Seasonal timing of life cycles and transmission • Resistance, abundance, and behavior of hosts NET EFFECTS!?

  13. Plague Wildlife Conservation Society Avian influenza Red Tides Rift Valley Fever Babesia Sleeping sickness Cholera Ebola Tuberculosis Parasites Yellow fever Lyme Dz


  15. Climate change will influence: • Food, water, and environmentally transmitted pathogens • E.g. Toxocara, Giardia,Toxoplasma • Rodent borne pathogens • E.g. tularemia, Hanta virus, alveolar hydatid disease • Vector borne pathogens • E.g. Lyme disease, West Nile Virus Human health in a changing climate: a Canadian assessment of vulnerabilities and adaptive capacity. Health Canada, 2008.

  16. Food & environmentally transmitted pathogens FOOD WATER Sea Rivers Drinking Seafood Meat Produce Processed Wildlife Pets Humans Livestock ? ? ? Hunter and Thompson 2005

  17. Effects of climate change on food and environmentally transmitted pathogens • Altered development and survival of pathogens in the environment • Driven by changes in regional precipitation and hydrology, and extreme weather events • Altered frequency and severity of outbreaks • Increase in existing health disparities for rural and remote regions

  18. Dog Roundworm Toxocara canis 2 cm

  19. ToxocaraEggs

  20. Retinal Lesions of T. canis Ocular Larva Migrans Zaman, Atlas of Medical Parasitology

  21. USA Seroprevalence of Toxocara • Estimate 14% of general public seropositive in 2008 national study • Covert toxocariasis (childhood asthma?) • Risk factors include: age, ethnicity, socioeconomic status, education, pet ownership, pica (blood lead levels) (Won et al., 2008)

  22. Toxocara in Canadians L. Polley Canadian Database For Animal Parasites

  23. Toxocaracanis absent in 1971 * * T. canis present in2006 T. canis present in 1971 * Unruh et al., 1973 Salb et al., 2008

  24. ToxoplasmaLife Cycle From: Dubey, 1993 PPP 3-10 d 1-3 d Patency ~ 2weeks

  25. Toxoplasmosis in people • NA Seroprevalence ~ 20% (9-40%), 33% globally • Often asymptomatic – BUT… • Acute toxoplasmosis • Lymphadenopathy, flu-like symptoms • Encephalitis (immunosuppressed) • Congenital toxoplasmosis • 140-1400 cases/year in Canada • Retinochoroiditis (common) • Hydrocephalus (rare)

  26. In terms of prevalence and disease burden, toxoplasmosis is probably the most important parasitic infection in the North American Arctic. Peter Hotez, January 2010, PLOS NTD

  27. Risk Factors • General Risk Factors (US population) • Consuming or working with raw ground beef, raw shellfish, rare lamb, locally produced cured, dried, or smoked meat, unpasteurized goat’s milk • Age, education, living conditions, race/ethnicity • Soil-related occupations • Having 3 or more kittens • Northern Risk Factors • Preparing and consuming (raw) country foods (caribou, seal and birds) • Demographics (age, sex, education, income) • Unfiltered surface water & natural water sources

  28. Water-borne Human Toxoplasmosis Victoria, BC, 1994-1995 Approximately 3,000 to 8,000 people infected 100 cases of acute toxoplasmosis (6-83 years old) 20 cases of ocular toxoplasmosis 8 cases with generalized toxoplasmosis 51 cases with lymphadenopathy PLUS 12 congenitally infected children, 3 with unilateral and 3 with bilateral retinal lesions

  29. Water-borne Toxoplasmosis Outbreak Bowie et al 1997

  30. Canadian Government survey in 2001 showed that two- thirds of First Nations reserves had water supplies that were at risk of contamination (King et al., 2009)

  31. Future trends in northern water issues • Climate-related impacts on the quantity, quality and accessibility of drinking water resources • Overwhelm existing drinking water treatment infrastructure • Changes in permafrost affecting waste-water treatment Furgal, C., and Prowse, T.D. (2008): Northern Canada; in From Impacts to Adaptation: Canada in a Changing Climate 2007, edited by D.S. Lemmen, F.J. Warren, J. Lacroix and E. Bush

  32. Climate change and Toxoplasmosis in Svalbard, Norway • Prevalence in polar bears has doubled in last decade (now 46%) • Detected in ring seals for first time • Warmer water temperatures • rapid development and survival of oocysts • influx of filter feeders Jensen et al., 2010

  33. PHAC Laboratory Surveillance Data for Enteric Pathogens, 2006

  34. Rodent borne zoonoses

  35. Effects of climate change on rodent borne disease • Largely driven by changes in regional precipitation and hydrology • Increased amplitude of changes in reservoir host abundance (boom bust scenarios) • Increased severity of outbreaks • Increased heterogeneity in spatial and temporal patterns of outbreaks • Changes in human behavior and land use

  36. Tularemia in Deer MiceSaskatchewan, Spring 2005 Wobeser et al., 2007 Affected Area (shaded) : 22,000 sq. km.

  37. Hanta virus H. Artsob, Feb 20 2007

  38. Hanta virus outbreak in SW USA • 6 yrs of drought 1987-1992 • Decreased predators of rodents • Intense rains in 1993 (El Nino effect) • Increased pinion nuts and grasshoppers • >10 fold boom in mouse population • Increased transmission to people Rocque et al 2008 OIE

  39. Occupational exposure to Hanta • Sweeping out a barn and other ranch buildings • Using compressed air and dry sweeping to clean up wood waste in a sawmill • Handling grain contaminated with mouse droppings and urine • Entering a barn infested with mice • Planting or harvesting field crops • Occupying previously vacant dwellings • Disturbing rodent-infested areas while hiking or camping • Living in dwellings with a sizable indoor rodent population • Trapping and studying mice* •

  40. Alveolar hydatiddisease Lantis 1980

  41. Global distribution E. multilocularis Eckert et al., 2000

  42. Effects of climate change on Echinococcusin N. America • Altered egg survival • Altered distribution and abundance of intermediate hosts • Altered interfaces among wildlife, domestic animals and people • Differential effects on species/strains • Concomitant with landscape change and global translocation of hosts/pathogens

  43. Drivers of emergence Media hyperbole Career making Increased reporting Increased awareness Improved diagnosis Newly recognized pathogen Change in virulence of pathogen Immunosuppression Malnutrition Change in feeding practices Movement of hosts Breakdown in water quality Changes in slaughtering/rendering/waste disposal Poor vector control Misuse of antimicrobials Breakdown in veterinary/public health infrastructure Invasion of nidi Increased urbanization Clearing land Allowing return of native vegetation/species Dam building Draining the swamp Changing agriculture practices Changing housing/shelter Population fluctuations of reservoir species Vaccine failures Lack of quarantine Reduced vigilance (diminishing returns) Climate change J. Iversen

  44. E. multilocularis in N. America *71 Cases in Alaska from 1951-1993 N1 A2 A4 *human cases E? * STRAINS From Nakao et al 2009 N= North American A=Asian E=European (Peregrine et al. in prep) N2 * MO (Map from Wilson et al., 1995)

  45. Global movement of pathogens • Establishment of European strain in dogs and/or wild canids in North America • Implications for public health • Owner seropositive? • 53 cases in Europe in 2008 • Implications for wildlife translocations

  46. Distribution and genotypes of red fox Aubrey et al., 2009

  47. Red fox and Arctic fox distribution IUCN Redlist

  48. Arthropod borne zoonoses

  49. Vector for: Lyme Disease, Tularemia, Human Granulocytic Anaplasmosis, Human Babesiosis Ogden et al., 2006 (In Health Canada, 2005: Health Policy Research Bulletin 11)

  50. Lyme disease(Borreliaburgdorferi) Feeding Egg Larvae Nymph Adult Feeding Feeding Randolph et al 2001