Lecture 6: Emerging Infectious Diseases – Zoonoses and the Environment Flashcards
Tuesday 21st January 2025
Has biodiversity decreased over recent years?
Yes, particularly due to industrialisation.
What does the Biodiversity Intactness Index (BII) estimate?
The Biodiversity Intactness Index (BII) estimates how much originally present biodiversity remains on average across the terrestrial ecological communities within a region.
“Among threatened wildlife species, those with population reductions owing to exploitation and loss of habitat share more viruses with humans.” Is this statement true?
Yes
What is a zoonotic disease?
A zoonosis is any disease or infection that is naturally transmissible from vertebrate animals to humans (WHO).
This event is called a ‘spillover’ event.
Has there been a large decrease in intact wilderness?
Yes
Has the average abundance of populations decreased over time?
Yes
What is a reservoir species?
A reservoir species is an organism that harbors a pathogen long-term without experiencing significant illness, acting as a natural source of the pathogen.
Can disease systesm have more than one species reservoir?
Yes, this makes them more complicated to treat
Reservoir species had faster life history characteristics than mammals overall, exhibiting traits associated with greater reproductive output rather than long-term survival.
Reservoir species had faster life history characteristics than mammals overall, exhibiting traits associated with greater reproductive output rather than long-term survival.
Why are birds, primates, and bats over-represented in scientific literature?
Because they cause zoonoses of high priority i.e. influenza, HIV, rabies, ebola, coronavirus
Are all the ilnesses bats are a reservois for viruses?
Yes
How many coronaviruses per species did a 2017 study find?
- Found an average of 2.67 Coronaviruses per species (sampled), extrapolated to an estimate of 3204 Coronaviruses across the 1,200 bat species.
What viruses are bats a reservoir for?
- Coronaviruses
- Ebola
- Rabies
- Chikungunya
What are both HIVs a result of?
Both HIVs are the result of multiple cross-species transmissions of simian immunodeficiency viruses (SIVs) naturally infecting African primates.
What gave rise to HIV-1?
- one transmission event, involving SIVcpz from chimpanzees in southeastern Cameroon, gave rise to HIV-1 group M—the principal cause of the AIDS pandemic.
- The contacts were likely caused by hunting/eating chimpanzees.
Is there continual ebola incidence?
Yes
What is the death rate of ebola?
40%
What is the R0 value for ebola?
R0 estimates vary between 1.5 – 2.5
Is the continual ebola incidence as a result of frequent ‘spillover’ events from wild species populations?
Yes
What is a natural reservoir of ebola?
Bats
What does MERS stand for?
Middle East Respiratory Syndrome
How did MERS arise?
Originated in bats, crossed to dromedary camels.
What is the reservoir species for MERS?
Camels are now a reservoir species, and required for persistence, as human to human transmission is low.
How many cases of MERS has there been since 2012?
2,500
What is the death rate of MERS?
35%
Did SARS in 2003 show the potential for the Coronavirus pandemic?
Yes, and Highly pathogenic emerging Coronaviruses relevant to humans (MERS & SARS) were number 3 on the WHO top emerging infectious disease list
Which species was coronavirus tracked back to?
Bat species
The COVID-19 pandemic was a consequence of…
ecological disruption and encroachment.
Summmary
- Huge human population growth.
- Humans have had a negative global impact on the environment.
- Putting stress on wild living animal species.
- Encroachment and interference with wild species provide a route of zoonotic EIDs.
- All only an introduction to EIDs.
