Question 19M.2.HL.TZ1.1b
| Date | May 2019 | Marks available | [Maximum mark: 3] | Reference code | 19M.2.HL.TZ1.1b |
| Level | HL | Paper | 2 | Time zone | TZ1 |
| Command term | Compare and contrast | Question number | b | Adapted from | N/A |
Ebola virus disease (EVD) is the disease in humans and other primates that is caused by the Ebola virus. Fruit bats are the reservoir for the virus and are able to spread the disease without being affected. Humans can become infected by contact with fruit bats or with people infected by the virus, their body fluids or equipment used to treat them.
The stacked bar graph shows the epidemiological data for the EVD cases in Conakry, the capital city of Guinea, surrounding suburbs and rural areas in Guinea from the beginning of January 2014 to the end of March 2015.
[Source: Adriana Rico, et al. “Epidemiology of Epidemic Ebola Virus Disease in Conakry and Surrounding Prefectures,
Guinea, 2014–2015.” Emerging Infectious Diseases 22.2 (2016): 178–183. PMC. Web. 23 Mar. 2017.
https://wwwnc.cdc.gov/eid/article/22/2/15-1304_article]
Based on the graph, compare and contrast the progress of the epidemic in the suburbs and rural areas.
[3]
a. start of epidemic/first cases in rural areas
OR
epidemic spread to suburbs later ✔
b. higher maximum number of cases/greater increase in rural areas
OR
converse for suburbs ✔
c. increase came earlier in rural areas «than suburbs»
OR
number of cases peaked earlier in rural areas
OR
more cases in rural areas «than suburbs» in 2014 ✔
d. decrease came earlier in rural areas «than suburbs»
OR
decreasing in rural areas but not in suburbs in 2015/by end of study period
OR
more cases in suburbs than rural areas in 2015 ✔
e. «large» fluctuations in both ✔
This was a timely question with Ebola epidemics again causing great problems in parts of Africa. Students were expected to have had some practice at analysing data relating to an epidemic because of this Skill in the programme: Analysis of epidemiological data related to vaccination programmes. It was assumed that candidates would understand terms such as ‘case’, ‘fatal case’, ‘infect’ and ‘treat’.
The skill required in this question was picking significant trends out of data with a great deal of noise. Only one similarity was accepted – the large week-to-week fluctuation in number of cases. The differences between the rural areas and the suburbs were that Ebola epidemic started earlier in rural areas, rose to higher peaks and started declining earlier.
