Environment

Question 1

What is environment?

Answer 1

Anything that isn’t an attribute of the host or the agent

Question 2

What can the environment be divided into?

Answer 2

Abiotic and biotic factors

Question 3

What are features of abiotic environment?

Answer 3

climate
weather ( sunlight, precipitation, wind, temperature)
topography
soil type
water

Question 4

Why do abiotic factors matter?

Answer 4

• it can affect where biotic factors are
• it can affect how long a disease can survive outside the host
• it can affect the mode of transmission of the disease

Question 5

What are features of biotic environment?

Answer 5

vegetation
animals (same species or different species acting as the vector, host, stressor or competitor)
humans

Question 6

What is an ecological niche?

Answer 6

A combination of biotic and abiotic factors that are required for survival

Question 7

What is needed for West Nile disease to survive?

Answer 7

mosquitos and birds of specific breeds transmit the disease (the mosquitos feed on the birds)
need horses and people, which are the dead end hosts because the mosquitos do not get the disease from them

Question 8

Why is it important to know the environmental niches for diseases?

Answer 8

• you can alter a component of the environment to try and eliminate the disease
• you can compare what environment a disease requires to determine if it will appear in other environments that do not have the disease yet

Question 9

Explain the Russian situation with liver flukes and moose

Answer 9

There was a limited watering holes for the moose to drink from and these watering holes had snails living in them, which is the intermediate host for the disease. As a result the moose were dying of live fluke infections.
To stop this, more watering holes were made in a certain area that was slightly more acidic so that the snails would not be able to survive

Question 10

How do you identify important factors within the environment?

Answer 10

Compare two situations, one with the disease and one without and decide what is different from the two situations.

Question 11

How is tuberculosis spread?

Answer 11

It has a large range of hosts and it is shed in secretions, saliva and nasal discharge

Question 12

What is a maintenance host?

Answer 12

A disease that can remain indefinitely within the host by transmission within the species
Ex/ skunks and rabies

Question 13

What is a spill over host?

Answer 13

a host that can transmit the disease, but the disease will not persist in the host without being introduced from other species.
ex/ dogs and rabies because they can get vaccinated

Question 14

What is a dead end host?

Answer 14

A host that can get infected but it cannot transmit the disease
ex/ people and rabies

Question 15

How is tuberculosis transmitted in Michigan?

Answer 15

• between deer either directly (through contact or fighting) or indirectly (sharing food)
• between deer and cattle most commonly indirectly (sharing food)

Question 16

How could TB be eliminated?

Answer 16

• Nuke the agent? Cant find it
• treat infected individuals? Need to find out who is infected first
• get rid of the host? It is a big market so people wouldn’t be in favour of that
• alter the environment? people aren’t cooperating

Question 17

What are some environmental manipulations that would help the TB situation?

Answer 17

• change the high density of deers
• stop feeding and baiting the deer
• reduce the contact between the deer and the cattle