Reservoirs, Transboundry, Epi Curves Flashcards
Who is John Snow
First published that cholera is transmitted by fecal-oral route and in water supply
Who is Robert Koch?
First to isolated bacterium B. Anthracis
Germ therory
Who is Ronald Ross?
Guy who discovered Malaria is transmitted by mosquitos
Who discovered that yellow fever is transmitted by mosquitos
Walter Reed
What is a habitat in which an infectious agent normally lives, grows, and multiplies?
Reservoir
What are three conditions that qualify something as a reservoir?
Is it naturally infected with pathogen
Can it maintain the pathogen over time
Can it transmit the disease to a new susceptible host
T/F: infection=disease=infectivity
False
Clinically ill animals that are reservoir commenter are probably infectious but so are asymptomatic animals
Not all sick animals are reservoirs
what is a vehicle of transmission?
An inanimate object which serves to communicate disease
Common vehicles= food, water, and IV drugs
Fomites=object that can be contaminated and transmit disease on a limited scale
What are the three levels of disease control
State
Federal
International
What is a problem with associated with vaccinating against reportable diseases?
Vaccines can show up as false positive results
Usually a positive result –> culling
What percent of emerging diseases are affecting humans are of animal origin?
75%
What is the OIE classification of notifiable disease?
Transmissible disease with potential for very serious and rapid spread, irrespective of national borders, that are of serious socio-economic or public health consequence and that are of major importance in the international trade of animals and animal products
What is infestation?
Invasion but not multiplication of an organism in/on a host (fleas/ticks, sometimes parasites)
What does it mean for a disease to be contagious?
Disease is transmissible form one human/animal to another via direct or airborne routes
What is a communicable disease?
Disease caused by an agent capable of transmission by direct, airborne, or indirect routes from an infected person, animal, plant, or contaminated inaanimate reservoir
Waves on an epidemic curve are separated by?
Incubation period
Epidemic curve that has a single group of new cases, shaped like a bell curve
Common source single point exposure
All animals exposed at the same time
Not contagious
Epidemic curve with random spikes, no clear pattern
Common source with intermittent exposure
All animals exposed at different times from the same source
Incubation period is not clearly shown
Epidemic curves with intermittent waves that progressively increase in size
Propagated source
Exposure if followed by “waves” of secondary and tertiary cases
Contagious disease
What does it mean for a disease to be endemic?
All factors influencing disease are relatively stable
New cases occur at low levels, regularly
Young individuals may enter population
Old individuals die or are removed
What are determinants of disease?
Host susceptibility Social Economic Physical environment Individual characteristics Behavior Genetics
What is a primary disease determinant?
major contributing factor to disease
MUST ALWAYS be there for disease to occur
What are secondary disease determinants?
Factors that make the disease more or less likely
What is the difference between and intrinsic and extrinsic disease determinant?
Intrinsic - internal to animal (age, breed, sex)
Extrinsic- external to animal (housing, medical treatment, ect)
What are disease determinants of the agent?
Mutations
-increase infectivity/ability to infect/new toxins/immune system evasion
Resistance
-mutation or lateral transfer
What are environmental determinants?
Demographics Macro climate Micro climate Housing and crowding Diet Stress
What are host determinants
Genotype
Breed
-> genetic susceptibility
Nutrition
Immunity
->overall health status
T/F: Diet and the animals nutritional status are intrinsic determinants of disease
False
Diet is extrinsic, management issue
Body condition and animals nutritional status are intrinsic
T/F: immunity from a vaccine is an extrinsic factor, but the status of the body being immune is an intrinsic factor
True
What is an emerging disease ?
PREVIOUSLY UNKNOWN disease that appears in a population
KNOWN disease suddenly appears in a new population
What is a RE-emerging disease?
KNOWN disease previously on the decline is becoming more common
What are the stages of cross-species disease emergence
- Pathogen exclusive to animal reservoir
- Animal reservoir transmits to humans or animals but NO transmission among them(dead end hosts)
- Animal reservoir tra mists to human/animals with few transmission cycles among them
- Animal reservoir transmits to human/animals with sustained transmission among them
- Pathogen exclusive to humans/new animals
What makes a disease likely to emerge?
Geographic host spot of emergency Host sp traits Host abundance Viral prevalence in host Epidemiological/contact interface
Host breath
Proportion known zoonoses in family
Phylogenic relatedness to those zoonoses
What are the 4 main drivers for pathogen emergence??
Land use changes (e.g. fraking/mining)
Food and agricultural systems (eg increased production/crowing/uniform genetics)
Environmental systems (eg hurricanes)
Human behavior (eg travel and tourism)
