Disease Ecology

Question 1

What is spillover?

Answer 1

When a pathogen jumps to a new species and thereby infects humans (zoonotic) or animals that are not the usual host

Question 2

What is a cluster?

Answer 2

An observation of an above-normal number of cases, normally aggregated in time and at a local scale

Question 3

What does it mean if a disease is endemic?

Answer 3

Normal number of cases/observed baseline infection rates of a persistent pathogen in a community or population, usually in a given area

Question 4

What is chikungunya virus?

Answer 4

An alphavirus, spread to people by the bite of an infected Aedes mosquito. Symptoms include fever, joint pain, headache, muscle pain, joint swelling, and rash. Only one vaccine is available in the United States. Rarely identified in Asia and Africa before 2006, but endemic transmission spread thru carribean in 2013, and by 2014 it was in the US.

Question 5

What is the West Nile Virus?

Answer 5

Arbovirus - anthropod borne & vector-borne, transmitted by mosquitos. Hosted mostly by wild birds. Mostly in middle east, africa, and europe, but was introduced to north america in 1999. Example of a zoonotic disease.

Question 6

What is pre-emptive medicine?

Answer 6

Development of symptoms is prevented altogether; describing discovery of genes that predispose certain individuals to particular diseases

Question 7

Knowledge of what interactions can be used to predict, prevent, and mitigate the transmission of infectious diseases?

Answer 7

Pathogens interactions with their hosts; and how they are embedded within a web of interactions among organisms in ecological communities

Question 8

What two categories are diseases typically grouped in?

Answer 8

Infectious and non-infectious

Question 9

What are non-infectious diseases caused by?

Answer 9

Genetic disorders, food, or the environment (e.g. ultraviolet radiation leading to skin cancer)

Question 10

What are microparasites?

Answer 10

Include the smallest organisms (viruses, bacteria, fungi, and some protists)

Question 11

What are macroparasites?

Answer 11

Organisms that can be seen with the unaided eye (e.g. helminths)

Question 12

What are vector-borne diseases?

Answer 12

Pathogens requiring another organism to transport them from host to host; these are the vector borne diseases

Question 13

What is the susceptible-infected, or S-I model, and how does it relate to population density?

Answer 13

Transmission between infected and susceptible hosts occurs at a particular rate, called the rate of transmission. The number of individuals who get infected during a given time is determined by the product of the rate of transmission, how many susceptible hosts there are, and how many infected hosts there are.

Question 14

What do STD transmission & vector-borne disease rates depend on instead of density?

Answer 14

The percentage of hosts infected (i.e. frequency dependent)

Question 15

What is the most competent reservoir for pathogens likely to be?

Answer 15

Habitat generalists

Question 16

White-footed mice (as compared to things like skunks & opossums) are responsible for infected what percentage of ticks with lyme disease?

Answer 16

92%

Question 17

What is a disease?

Answer 17

A pathological condition of a part, organ, or system of an organism resulting from various causes, such as infection, genetic defect, or environmental stress, and characterized by an identifiable group of signs or symptoms

Question 18

What 3 factors often underlie the resurgence of both human and wildlife infectious diseases?

Answer 18

Drug resistance, environmental change, and globalization

Question 19

What is the definition of ecology?

Answer 19

The study of the distribution and abundance of organisms and how organisms interact with their environmenet

Question 20

What is the definition of disease ecology?

Answer 20

The study of ecological interactions between parasites/pathogens and their hosts

Question 21

What is a parasite?

Answer 21

A smaller organism that lives on or in and at the expense of a larger organism called a host

Question 22

What are some ways to classify parasites?

Answer 22

Size, where they live in the host, host range, and transmission style

Question 23

What are viruses?

Answer 23

An infectious particle that reproduces by commandeering a host cell and using its machinery to make more viruses. Made up of ss/ds DNA/RNA genome insides a protein shell (capsid). Some viruses have an external membrane envelope.

Question 24

What is mutation through antigenic drift?

Answer 24

Random mutation in influence genes explain why there is no long-lasting immunity to the flu

Question 25

Where do ectoparasites live on the host?

Answer 25

Confined to the exterior of the host's body (most parasitic arthropods - ticks, lice, ect.)

Question 25

What are the two types of host ranges and an example of them?

Answer 25

Generalists: parasites with a broad host range (rabies - most mammals) and Specialists: parasites with a narrow host range (whirling disease - salmon and trout; measles - humans only)

Question 26

Where do endoparasites live on the host?

Answer 26

Within the host's body (parasitic worms, all viruses, many bacteria)

Question 27

How do directly-transmitted parasites work?

Answer 27

Parasites transmitted directly from one host to another without an intermediate host of another species, vector, or environmental stage

Question 28

How do environmentally transmitted parasites work?

Answer 28

Parasites with free-living environmental life stage between hosts

Question 29

What are vehicle-borne parasites?

Answer 29

Parasites/pathogen enters the host by means of a vehicle (e.g. food-borne or water borne)

Question 30

What are indirectly-transmitted parasites?

Answer 30

Parasites requiring an intermediate host or vector for transmission between hosts

Question 31

What is a vector?

Answer 31

A living carrier (often arthropods) that transports an infectious agent from an infected to a susceptible host