lecture 32- the ecology of human infectious diseases Flashcards
What are the different types of agents?
1- Bacterial
2- Viral
3- Fungal
4- Parasitic
5- Prion
Explain how the following are all related: host, vector, agent, and environment.
Host: organism harboring the disease.
Vector: organisms that carry and transmit the infectious pathogen to the host.
Agent: the microbe that causes the disease.
Environment: the external factors that allow transmission.
What is zoonoses (zoonotics)?
Diseases and infections of vertebrate animals that can be transmitted to humans.
What are the 2 kinds of zoonotic diseases?
Emerging:
- Newly appear in humans (or now rapidly increasing in incidence or range)
- E.g., Ebola, HIV/AIDS, COVID-19
Endemic:
- Occur intermittently
- Triggered by events
- E.g., Anthrax, leishmaniasis, Rift Valley fever
What is a zoonotic spillover?
Transmission of pathogens from wild animals to humans.
What are the seven major anthropogenic drivers of zoonotic disease emergence?
1- Increasing demand for animal protein.
2- Unsustainable agricultural intensification.
3- Increased use and exploitation of wildlife.
4- Unsustainable utilization of natural resources accelerated by urbanization, land use change, and extractive industries.
5- Travel and transportation.
6- Changes in food supply chains.
7- Climate change.
Explain the following anthropogenic driver of zoonotic diseases emergence: increasing demand for animal protein
Produce way more meat than we did before.
- Southeast Asia, Sub-Saharan Africa: rapid increase
- Per capita increase in animal consumption + population growth
Pigmeat is the most popular meat globally, but production of poultry increasing most rapidly.
Explain the following anthropogenic driver of zoonotic diseases emergence: unsustainable agricultural intensification
Increased demand –> intensification and industrialization of animal production
Genetically similar animals are vulnerable to infection.
- Close proximity, poor conditions.
Explain the following anthropogenic driver of zoonotic diseases emergence: increased use and exploitation of wildlife
Bushmeat: harvesting wild animals as a source of protein
Recreational hunting, decorative, medicinal, and commercial products
New roads in remote areas –> increase access
Explain the following anthropogenic driver of zoonotic diseases emergence: unsustainable utilization of natural resources accelerated by urbanization, land use change, extractive industries
Rapid urbanization leads to novel contacts with wildlife, livestock, and people
- Irrigation systems encourage vector-borne zoonoses
- Deforestation and fragmentation
- Ecological tourism
- Encroachment into wildlife habitats
Explain the following anthropogenic driver of zoonotic diseases emergence: travel and transportation
Diseases can move around the world faster than incubation periods
Increasing human travel and trade
Explain the following anthropogenic driver of zoonotic diseases emergence: changes in food supply chains
Increased opportunities for cross-contamination
Difficult to trace
Rapidly expanding and poorly managed wet markets
Explain the following anthropogenic driver of zoonotic diseases emergence: climate change
Zoonoses are climate sensitive and will thrive in warmer wetter climates.
What are the 2 ways in which viruses evolve?
1- Antigenic drift: Point mutations cause small changes in the surface antigens (H & N).
- These can lead to regional epidemics in populations that have had no previous exposure.
2- Antigenic shift: “Genetic reassortment” = the process by which the whole H-N combination changes.
- Produces novel flu strains distinct from all previous strains –> potentially causing a pandemic.
Why does corona virus have its name? What are its symptoms?
Named “corona” for the crown-like arrangement of spike-shaped proteins on the surface
Some cause mild upper respiratory illness (common cold)
