Factors that Affect the Spread of a Disease

Question 1

List the 4 terms to describe the occurrence of infections.

Answer 1

1. Endemic.
2. Sporadic.
3. Epidemic.
4. Pandemic.

Question 2

Define endemic.

Answer 2

The infection is prevalent at a constant rate within a population.

Question 3

Define sporadic.

Answer 3

Diseases that occur irregularly within a population.

Question 4

Define epidemic.

Answer 4

An increase in cases of disease over what is considered normal.

Question 5

Define pandemic.

Answer 5

An epidemic that spreads across multiple contents.

Question 6

List the 4 factors affecting the spread of a disease.

Answer 6

1. Growth of the pathogen.
2. Density of the host population.
3. Mode of transmission.
4. Population mobility.

Question 7

Describe the growth of a pathogen as a factor affecting the spread of a disease.

Answer 7

• The increased size of the pathogens increases the risk of transmission.
• Some pathogens have a very high rate of replication which increases their chance of spread.
• The favourable conditions can shorten the reproductive cycle increasing the population size.

Question 8

Describe the density of the host population as a factor affecting the spread of a disease.

Answer 8

The more densely populated a community the more likely organisms are to come into contact with an infected organism. Therefore increasing susceptibility. Zoonoses are more likely as reduced habitat leads to greater interactions between humans and wild animals.

Question 9

Describe the mode of transmission as a factor affecting the spread of a disease.

Answer 9

• Multiple modes of transmission increase the likelihood of transmission.
• One mode of transmission can switch to another depending on the environmental conditions.

Question 10

Describe population mobility as a factor affecting the spread of a disease.

Answer 10

Human diseases have been affected by changes in the mode of transport. Infectious diseases could only spread as fast and as far as people could walk. However, over time with the evolution of transport people can now spread a disease across the world. Diseases can be spread as a result of trade.