Viruses (A)
Cell Structure and Function
Viruses
In March of 2014, the Ebola virus began to spread quickly in the West African countries of Sierra
Leone, Senegal, Liberia, Guinea, and Nigeria. The virus, known as Hemorrhagic Fever, is spread
through contact with skin and body fluids of infected individuals or animals. The symptoms can
appear between 2 and 21 days after infection and may include high fever, headache, muscle aches,
sore throat, and stomach pain. As symptoms progress, the infected individuals will experience a
decrease in the number of blood-clotting cells which leads to internal and external bleeding. The
mortality rate of Ebola victims is up to 90% of those infected.
The data below shows the number of total cases per month in the countries named above.
Cumulative Infections and Monthly Deaths From Ebola
1.
Report Dates
Cumulative Infections
Monthly Deaths
February 2014
59
33
March 2014
137
93
April 2014
241
162
May 2014
421
226
June 2014
759
467
July 2014
1603
887
August 2014
3707
1848
Calculate the percent of the infected who have died from the disease and record the figures in
the chart below. (Percent of death = (monthly deaths / cumulative infections) x 100)
Month
Percent of Death
February
55.93%
March
67.88%
April
May
June
July
August
1
Viruses (A)
Cell Structure and Function
2.
The mortality rate of Ebola victims is about 90%. However, your figures from question 1 do not
support this per month. Why? What other factors need to be taken into account with this data?
3.
Create a scatter plot using the data from the first page. Use the total monthly deaths as the
x-values and the cumulative infections as the y-values.
Ebola Virus 2014: Cumulative Infection vs. Monthly Deaths
4000
3800
3600
3400
3200
3000
Number of Cumulative Infections
2800
2600
2400
2200
2000
1800
1600
1400
1200
1000
800
600
400
200
0
0
200
400
600 800 1000 1200 1400 1600 1800 2000 2200 2400
Number of Monthly Deaths
2
Viruses (A)
Cell Structure and Function
4.
What is the percent increase of infection during the time period from February 2014 to August
2014? (First find the difference between the numbers. Then divide the difference by the original
infection of 59. Multiply this result by 100.)
5.
Draw a trendline through the data on the graph.
6.
What is the rate of increase on your graph (slope)? Use your trend line to approximate the
slope. Remember: slope is the increase of the y-value divided by the increase of the x-value.
7.
What is the y-intercept of your graph? This represents how many deaths will there be if no one
is infected. Look at where your trendline approximately crosses the y-axis.
8.
Create an equation to describe the line. (Hint: y = mx + b, where m is the slope and b is the
y-intercept.)
9.
The equation means that for every ________ deaths, there are _________ as many cumulative
infections that occur.
Graph the total number of people infected per month on the chart below.
The Growth of Ebola Cases in West Africa in 2014
Total Number of Ebola Cases
10.
3200
2800
2400
2000
1600
1200
800
400
0
Jan
Feb
Mar Apr
May Jun
Jul
Aug
Sep
Oct
Nov Dec
Month
3
Viruses (A)
Cell Structure and Function
11.
Is the relationship linear? If not, describe the relationship. (Hint: what is the root word in
‘linear’?)
12.
What does the pattern of infections seem to be from one month to the next? (Use estimation;
the relationship doesn’t have to be exact.)
13.
It is estimated that 20,000 people will become infected before the disease is able to be
controlled. What month will the number of infected people reach a total of 20,000? (If you have
a graphing calculator, use your equation to figure out how many months it will take to reach
20,000.)
14.
What are some measures the countries involved can take to decrease the spread of the Ebola
virus?
15.
How might these measures affect the people living in or visiting those countries?
4