Module 5 Flashcards
Emerging diseases
Explain the terms zoonotic, zoonoses, epidemic, pandemic, epidemiology.
- zoonotic, zoonoses: Singular zoonosis, plural zoonoses, or zoonotic diseases. Disease caused by a pathogen that has jumped from an animal to a human.
- epidemic: sudden increase of a disease within a population, more than expected.
- pandemic: an epidemic that spreads across regions
- epidemiology: the study of the determinants, occurrence, and distribution of health and disease in a defined population.
Describe how phylogenetics can be used in studying viral diseases?
- Identify variants
- Predict changes in biology of virus
- Speed up contact tracing
- Identify super-spreader events
Discuss the reasons zoonotic diseases are becoming more common?
human induced drivers such as:
1. land-use changes,
2. human-wildlife interactions
3. biodiversity loss: It all centres on the idea that disruption to ecosystems leads to disruption of the interaction of pathogen, disease vectors and hosts.
Name three sources of disease?
- invasive species
- pathogen adapting to new hosts ie, zoonotics
in humans, but also relevant to other species - benign pathogens adapt to become disease
causing organisms
Discuss the characteristics and usefulness of ecological network models?
Models of ecosystem networks enable scientists to develop predictive models. They help us prioritise which areas we need to monitor for the appearance of new zoonotic diseases. e.g. predicting high rates of virus sharing in the tropics among mammals, particularly among rodents and bats.
Discuss three ways in which a change in biodiversity can affect disease transmission?
A change in biodiversity can affect disease
transmission by changing…
1. The abundance of the host or vector
2. The behaviour of the host, vector or parasite
3. The condition of the host or vector
Conclusion: The influence of biodiversity loss in emerging disease has more to do with how organisms respond to disturbance than with dilution of biodiversity
Explain why the impact of disease is most dramatic when it first arrives in a population?
because the new host has not evolved resistance to it (immune defence not yet ‘trained’)
Explain, using example, how resistance to disease is natural selection in action?
Resistance to disease: Over time, individuals of the host species that can easily produce antibodies will survive and reproduce = natural selection in action. Example: rabbits in Australia have been exposed to several devasating diseases such as myxomatosis in mid 1950’s and a large number rabbits died. The survivors had an immune system that had adapted to fight the virus, potentially a genetic advantage, and this was passed onto future generations which saw the population re-establish itself after around 10 years.
Discuss how emerging diseases are an example of the race between fast and slow evolution?
Pathogens also adapt to survive the host’s immune system, therefore new variants appear which the host does not yet have antibodies for. It’s a race between the quick evolution of viruses and the slow evolution of the host’s immune system. Host’s may require several generations (years) before the population has antibodies, whilst viruses have shorter life spans and can adapt quicker.
Explain what is meant by the term antimicrobial resistance?
Antibiotic resistance occurs when bacteria develop the ability to survive after exposure to antibiotics. Major concern for future of medicine, as antibiotics are a key tool in fighting bacterial disease today.
Antibiotic resistance is the process of natural selection in action. all bacteria that is non-resistant dies from the antibiotics, the antibiotcs that have resitance survive and reproduce, and have an ideal environment to take over without competition.
Describe what is an energy budget and it’s main components.
Energy budgets consist of a simple set of rules that specify how an individual organism acquires and energy and building blocks from their environment and distributes it to fuel their life cycle.
Energy is consumed and then used for growth, maturation and reproduction (and some in reserve).
The budget is limited by food intake, efficiency of digestion and metabolism.
Describe the various ways multiple stressors can interact to impact an organism?
Lots of simultaneous changes: climate change, habitat fragmentation, agriculture and urbanization, pollution, and more.
The impact of multiple stressors can be:
1. Additive = impact equivalent to sum of each stressor
2. Synergistic = effect is greater than the sum of separate effects
3. Antagonistic = combined effect is less than the sum of separate effects
4. Neutralizing = results in no effect at all
Discuss the conditions under which disease is of most concern for conservation?
When:
* It is new (individuals and populations have not built immunity/resistance)
* Populations are small
* There is low genetic variation
* There are multiple stressors
…because it reduces the resilience of these populations and increases their vulnerability to extinction
