Question 19M.2.HL.TZ1.1c
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.2.HL.TZ1.1c |
| Level | HL | Paper | 2 | Time zone | TZ1 |
| Command term | Suggest | Question number | c | 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]
Suggest two reasons for the overall decline in the epidemic after week 51.
[2]
a. «overall decline due to» fewer cases in rural areas ✔
Answers relating to people who died from the disease or develop immunity to it:
b. fewer cases due to deaths of people who had the disease/people recovering
OR
more people vaccinated/became immune/made antibodies/were not vulnerable to infection ✔
Answers relating to health care workers or availability of resources:
c. more doctors/nurses/medical equipment/treatment centers/hospitals/spending/aid/NGOs ✔
Answers relating to medical techniques used to tackle the epidemic:
d. better treatments/infection control/hygiene/quarantine/new vaccine/new antiviral drugs ✔
Answers relating to the public and patients:
e. education/better awareness/avoidance of infection/taking precautions/vaccination accepted ✔
Answers relating to reservoirs of infection:
f. fewer infected people «who could spread infection»/fewer bats/less contact with bats ✔
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’.
A wide range of possible reasons for the decline in the epidemic was accepted here and most candidates scored both marks. The commonest type of misunderstanding was that there might be few people left to become infected. Given that the total number of cases was only in the thousands and the population of Guinea must be in the millions, that explanation for the decline was implausible. As this was a suggest question and candidates are not required to have specific knowledge of the Ebola epidemic, any reasonable answer was accepted even if it was not historically true.
