Lecture 31: Ecology of Diseases Flashcards
What is the epidemiology triad?
- Host (organism that gets sick)
- Agent (virus/bacteria)
- Environment (mediates interactions between agent and host)
- Vector (third party that houses the agent
How does invasion affect epidemiology? (burmese python in fla example)
Ex: burmese python escapes exotic pet industry –> reduces biodiversity (uncontrolled consumer) –> reduces host diversity so now mosquitos bite more of a certain rat that carries a disease
What are zoonotic pathogens?
Diseases and infections of vertebrate animals that can be transmitted to humans.
What is the hypothesis for zoonotic spillover in Africa?
loss of forest cover and consumption of bushmeat drives contact between humans and wild hosts, leading to more infections (such as fruit bats containing zika, ebola, HIV)
What is bushmeat?
meat of wild animals captured in forested areas are brought to urban areas for sale
How does forest fragmentation affect the spread of disease?
Deforestation increases the edge of contact between humans and wild reservoirs (bats) of pathogens
How did the Nipah virus outbreak occur in Malaysia?
Areas converted to pig farming were near forests –> bats came to farms and shat on the pigs which wallowed in the infected species –> when the infected pigs were moved, disease spread
How do viruses evolve?
- antigenetic drift: point mutations cause small changes in surface antigens
- antigenetic shift: the H and N antigens completely reorganize when two different viruses exchange genomes
How did influenza evolve?
Influenza firus covered in H and N enzymes –> different combos of H and N require different antibodies to fight (flu virus evolves)
How do pigs act as mixing vessels for virus reassortment
If birds are sick and shit in pig pens, pigs wallow in shit.
If humans also give pigs diseases, these two viruses can mix and cause reassortment, making a new evolved virus that humans are not immune to.
