Wildlife Disease Epidemiology Flashcards
What is Wildlife?
Individuals whose phenotype has not been selected by humans, and animals that are not living under human supervision, in captivity or managed in any way (free-ranging non-domestic wildlife)
For One Health, wildlife includes all animals and plants
Are diseases bigger now than they used to be?
Resilience in animal populations is declining.
At low population levels, stochastic events e.g. a disease epizootic, can cause local extinction and hypothetically extinction of a species
Real problem is not disease itself, but the loss of resilience (=species/population decline and loss of response diversity)
Is ebola emergence in West Africa a product of lowering of the ecosystemic temperature through habitat destruction, human population expansion and agriculture.
Vertebrate pathogen evolution, emergence and persistance are influenced by himans through e.g. landscape change, agriculture and animal domestication - TB, brucellosis, rinderpest, measles, PPR, rabies, HPAI, SARs, Nipah, Ebola, HIV etc.
Pathogens spread by human transportation systems, globally, adds an unnatural load
Immunological systems adapted to a less dynamic world are unable to adapt rapidly enough to this tidal wave of pathogenic organisms spilling over, e.g. WNV, WNS, HPAI, H5N1, Bd, Ash tree fungus
What do you know about zoonotic disease stemming from wildlife?
Emerging infectious diseases (EIDs) are a significant burden on global economies and public health.
Their emergence is thought to be driven largely by socio-economic, environmental and ecological factors, but no comparative study has explicitly analysed these linkages to understand global temporal and spatial patterns of EIDs
What are the stages of zoonotic disease stemming from wildlife?
Stage 1:
Agent only in animals
No transmission
Stage 2:
Primary infection
Transmission to humans only from animals
Stage 3:
Limited outbreak
Transmission to humans from animals or (few cycles) humans
Stage 4:
Long outbreak
Transmission to humans from animals or (many cycles) humans
Stage 5:
Exclusive human agent
Transmission to humans from humans only
What will the size of an issue depend on regarding wildlife disease?
Potential impact
Proximity to other species
Maintained or not
What do we know about microorganism and parasite diversity?
They have a role in biodiversity
Millions in a cubic foot of soil!
Parasitism has a cost but co-evolution tends to reduce the impact
What can Biodiversity, natural populations and ecological systems do?
Affect pathogen dissolution, dilution and can moderate virulence in the microbial community (and occasionally amplify)
What is wildlife (regarding pathogens and disease)?
A source of pathogens (directly or indirectly through evolution in new host)
But largely a victim of emergent diseases
What are drivers for pathogen evolution and emergence?
Largely anthropogenic (behavious, agroecology, livestock breeding and production systems, human and domestic animal demography, climate
What is surveillance in wildlife populations?
Should be situation based
Use of pathology and seroepidemiology are particularly useful disciplines
Is control of infection in wildlife populations possible?
It is challenging, but in some unique situations it is possible.
Is early detection of emergent wildlife disease and human pathogens from animal sources possible?
It has improved with gene technologies but remains difficult, perhaps impossible!
Situation based wildlife surveillance and seroepidemiology are valuable tools for monitoring pathogens in the environment
What do solutions for wildlife disease lie in?
Lie in modification of human behaviour, radical changes in domestic animal breeding and genetics, husbandry and production systems, agroecology, land use and urban planning and through more attention to biodiversity and ecosystem conservation
How can risk of extinction from infection be mitigated?
Through vaccinology and biosecurity from domestic animal and human sources of infection.
What is Wildlife Health?
The physical, physiological, behavioural and social well-being of free-ranging animals measured at an individual, population and wider ecosystem level, and their resilience to change such as habitat loss
What can climate change impact?
Behaviour
Development
Fecundity
Mortality
Of both host species and their parasites
How can the effects of changes caused by climate change be seen?
In how hosts and parasites interact
In how species communities interact
In where species are to be found
What do we know about community interaction and pathogen extinction/loss of endemic parasites?
Can reduce disease
Can also release pathogenic organisms from competition?
What do we know about community interaction and host-pathogen interactions?
Can have positive and negative impacts
What happened with the near extintion of abalone?
Driven by rickettsial disease
Had ripple effects on communities across a number of trophic levels
What happens when coral is bleached?
Reduced mucous with antibiotic properties
What are some community interactions?
Biodiversity loss
Inhibition of disease vector predators
Inhibition of disease vector competitors
What might happen to species movements with climate change?
Increasing temps may encourage species to move to higher altitudes or higher climates
The asian tiger mosquito across Europe and the Americas is an example related to the risk of Chikungunya
Migration routes may alter
- Long-distance migrations may prevent build up of parasites
Changes in vector life stages
