Emerging infectious diseases - Background Flashcards
What are the major global threats when it comes to changing ecosystems? (3)
- Biodiversity loss
- Global warming
- Zoonotic risk
What are the drivers of the increased extinction of species since 1900? (5)
- Changes in land and sea use
- Direct exploitation of organisms
- Climate change
- Pollutions
- Invasion of alien species
What are the underlying causes for the drivers of extinction of species? (3)
- Twofold increase in human population
- Fourfould increase in the global economy
- Tenfold increase in global trade
Which planetary boundaries have currently been exceeded? (4)
- Climate change
- Biodiversity loss
- Land usage
- Disturbance of biochemical flows
What are important underlying causes for the increase of zooneses in the past 40 years? (3)
- Increased human incursion into forests
- Increased numbers of farmed animals
- Increased trade/transport of animals
What is a major cause for the emergence of AIDS?
Increased human incursion into forests
What are underlying factors for the emergence of AIDS? (3)
- Deforestation
- Expansion of human communities
- Increased connectivity & global travel
What are underlying causes for the emergence of human-pathogenic avian influenza? (3)
- Increased numbers of poultry
- Avian-human contact at poultry farms & live animal markets
- Spillover into migratory birds
What are underlying causes for the emergence of SARS-CoV/SARS-CoV-2? (2)
- Increased capture and trade of wildlife
- Wildlife-human contact at live animal markets
What is the current WHO roadmap for the prevention of emerging pathogens aimed at?
Containing pathogens after they have emerged
What are important pillars of the WHO roadmap for the prevention of emering pathogens? (4)
- Establish surveillance for early warning
- Acquire better understanding of pathogenesis, natural history & epidemiology
- Develop and implement improved diagnostics, preventitives and therapeutics
- Provide financial support for these measures
Why is it important to switch to a proactive approach in countering emerging infections?
It is easier to prevent emergence than to counter diseases after emergence
What is an emerging infectious disease (definition)?
Infectious disease that has recently:
1. Increased in incidence, geographic range OR
2. Moved into a new host species OR
3. Been caused by newly evolved pathogens
What is a natural reservoir host (definition)?
Species in which a pathogen endemically circulates, and is considered to have coevolved with
What is an intermediate/amplifying host (definition)?
Species infected by a pathogen that is not the reservoir host, but play an important role in spillover to humans
What is a vector (definition)?
Carrier/disease-causing agent from an individual to a non-infected individual or to its food/environment
What are often vectors of infectious disease?
Non-vertebrate species
How many % of emerging infectious diseases in humans originate in animals?
> 60%
Which two animal classes are important sources of emerging zoonotic infections?
- Birds
- Mammals
Which two groups of birds are important for emerging zoonitic infections? Are these the largest numbers of species?
- Anseriformes (waterfowl)
- Galliformes (ground-feeding birds)
No, these are not the largest classes, but are the classes that are frequently in contact with humans
What is the most abundant bird species in the Netherlands?
Chickens (captive)
(non-captive = sparrow)
What are the two biggest groups of mammals (numbers of species)?
- Rodentia (rodents)
- Chroptera (bats)
True or false: some orders of birds/mammals have a higher chance of carrying zoonotic viruses
False: in principle all groups have equal chance, but some are in closer contact with humans/more abundant, increasing chance of transmission
Why would it be advantageous to know which orders of animals are more likely to carry zoonotic disease? (4)
- Allows for targeted surveillance
- Allows for study of underlying mechanisms in carrier species
- Allows for prevention
- Helps to predict epidemiology
What is the role of domesticated animals in zoonosis?
Often serve as an intermediate host for zoonotic infectious diseases
How many % of zoonotic diseases in humans is associated with current agricultural practices?
~50%
Why do current agricultural practices increase the chance of emerging infectious diseases?
Negative effects on biodiversity and contact rates with domestic and wild animals
Which factors at live animal markets make zoonoses more likely? (5)
- Overcrowding
- Poor hygiene
- Mixing of diverse species
- Travel of purchased animals
- Complex trading chains
What are characteristics of avian influenza A viruses that make it likely to spead at live animal markets? (3)
- High diversity of host species
- High mutation rate
- Possibility of reassortment
