Emerging infectious diseases Flashcards
What percentage of newly emerging diseases are zoonotic?
~ 75%
A previously unknow disease that suddenly appears in a population is known as what?
Emerging dz
A known disease that suddenly appears in a new population is known as what type of disease?
Emerging
What is a re-emerging disease?
A known disease, previously on the decline, that is becoming more common and will likely to continue to do so
What are the three steps taken to act against emerging diseases?
Detection: identifies something abnormal or unusual/ dx dilemma
Investigation: communicates dz importance
Response: implementation of dz control/management
What are the stages of cross-species disease emergence?
- pathogen exclusive to an animal reservoir
- animal reservoir transmits to humans/other animals, but no transmission among them (like a dead end host)
- animal reservoir transmits to humans/other animals with a few cycles of transmission among them
- animal reservoir transmits to humans/other animals with sustained transmission among them.
- pathogen exclusive to humans/new animal reservoir
What percentage of known pathogens on have one host?
~ 37%
Besides economic costs, what other costs can outbreaks of emerging dz cause?
Emotional, physical (toll on victims, stress on family members of those effected etc), life lost (victims, animals that must be culled, Loss of genetic lines (when culling animals ) etc
What two factors are combined to rank the risk of dz/virus spill over? (“anticipating the jump”)
Virus independent traits + Virus specific traits = risk of spill over
What are examples of land use changes that drive pathogens to emerge?
Encroaching into natural environments: deforestation and habitat fragmentation
Practices like: fracking, dredging, quarrying, mining beach sand
How does urbanization play a role in driving pathogens to emerge?
Increases density of susceptible human populations
Changing land use and climate influence _____ borne and ________ borne disease transmission
Waterborne and vector-borne
What are some examples of food and agricultural systems practices that drive pathogens to emerge?
Using human sewage as fertilizer (2nd/3rd world countries)
Global trade - carries pathogens across the world
management practices and biosecurity on farms: what happens with animal waste, vaccine protocols, mixing of animals etc
What negative effects can an increase in livestock production have in regards to emerging diseases?
Results in uniform genetics, production, and susceptibility to diseases/infections
increased density of herds promotes transmission
What are the four major determinants of emergence?
Host: susceptibility
Pathogen: type of agent
Reservoir: phylogenetic distance
Transmission: reservoir size, pathogen prevalence, contact frequency
T/F: zoonotic pathogens are twice as likely to be associated with emerging diseases
TRUE
What percentage of KNOWN pathogens that infect humans, are zoonotic?
61%
What pathogen adaptations promote emergence?
Increased AB resistance
Increased virulence
Mutations that enhance transmissibility within or between species
Evasion of host immunity
T/F: Pathogens are less likely to cross between closely related species than distant ones
FALSE
more likely
T/F: Pathogens that some how cross between distantly related species often cause very different, often MORE severe disease
TRUE
What factors will increase the probability of transmission from a reservoir to a new host?
Increase in abundance of the reservoir
Increasing pathogen prevalence in the reservoir
increasing contact between the reservoir and new host
How are animal disease outbreaks typically controlled?
Mass culling Test and slaughter Quarantine Vaccination / ring vaccination Prophylactic antibiotic use
