Identify the week and year in which the first cases were recorded in the suburbs.

Week:

Year:

Based on the graph, compare and contrast the progress of the epidemic in the suburbs and rural areas.

Suggest two reasons for the overall decline in the epidemic after week 51.

Compare and contrast the data for Conakry with the data for the three suburbs.

Suggest reasons for the high percentage of fatal cases at Ebola treatment centres.

Based on these data, outline the evidence that T-705 has potential to be used as a treatment for EVD.

Explain how vaccination can lead to the production of B cells specific to the Ebola virus.

Suggest possible reasons for the difficulty of preventing or controlling a viral epidemic such as the 2014 EVD epidemic in a remote rural region.

week 34 AND 2014 ✔

both needed

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 ✔

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 ✔

differences:
a. Conakry has more cases than any of the suburbs
OR
more cases in total in the suburbs than in Conakry ✔

b. more male cases in Conakry whereas more female cases in suburbs ✔

c. higher «% of» fatal cases at Ebola treatment centers in suburbs than in Conakry ✔

similarity:
d. in both Conakry and suburbs «% of» fatal cases in treatment centers is higher than outside ✔

a. most serious cases are in/are taken to treatment centers
OR
treatment centers are set up where there are most cases/most serious cases ✔

b. long time/distance to travel between contracting disease and arrival at treatment center
OR
travel to treatment center weakens/upsets/harms the patient ✔

c. Ebola is a virulent disease/Ebola virus mutated «to become virulent»
OR
little known about Ebola/new disease so treatments not yet developed ✔

d. no/not enough vaccine/antiviral drug available «in 2014/15»
OR
antibiotics do not work against viral diseases ✔

e. secondary infections/Ebola patients infected with other diseases/other Ebola strains
OR
ineffective hygiene/cleaning/sterilization/use of contaminated equipment/disposal of corpses ✔

f. small number of staff relative to patients/treatment centers overcrowded/swamped with patients
OR
insufficient equipment/supplies for large number of patients/with the rapid rise in patients ✔

g. better reporting at Ebola centers/deaths due to Ebola not reported in rural areas ✔

a. cells not killed/few cells killed «even at high concentrations» ✔

b. «T-705» effective/viruses reduced/viruses killed at 100 μM
OR
«T-705» very effective/viruses much reduced/nearly all viruses killed at 1000 μM ✔

c. virus concentration decreases as T-705 concentration increases ✔

d. drug has «high» potential for treatment «at high enough concentration» ✔

a. vaccine contains Ebola antigens ✔

b. vaccine «could» contain weakened/attenuated/dead/killed form of «Ebola» virus/virus genetically modified to express an Ebola/viral protein ✔

c. phagocyte/macrophage engulfs the antigen/presents the antigen to T cell ✔

d. antigen recognized by «specific» T cells/binds to T cells ✔

e. «activated» T cells activate «specific) B cells ✔

f. «activated» B cells make the antibodies «against Ebola» ✔

g. B cells divide forming «clone of» plasma cells/producing more B cells specific to Ebola ✔

a. poor transport infrastructure/poor communication/bad roads/difficult access/no maps/support slow arriving/scattered population ✔

b. poor education/understanding of disease amongst health workers/local population
OR
continued contact with infected people / other example of unsafe actions ✔

c. more sources of infection such as bats/difficult to find sources of infection ✔

d. lack of/limited access to medical care/doctors/health care workers ✔

e. lack of/no access to/unaffordability of treatment centers/medicalsupplies/equipment/antivirals/drugs/vaccine/treatments ✔

f. refusal/reluctance in local population to be vaccinated
OR
difficult to find/reach everyone to vaccinate them/repeat the vaccination ✔

g. migration of people spreads the infection ✔

h.poor sanitation/lack of clean water ✔

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’.

Nearly all candidates read from the graph the week and year in which the first cases were recorded in the suburbs.

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.

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.

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’.

This was another question where the skill was in picking out significant trends. Differences between individual suburbs were not significant so all the answers accepted were either similarities or differences between the capital city and the suburbs generally. Most but not all candidates made two or more statements about the data that were significant enough to score marks. Some students treated percentages as though they were absolute numbers and for example added the percentage of fatal cases in and outside treatment centres together, which does not give a meaningful total.

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’.

This was a more difficult question. We might expect fewer fatalities in percentage terms at treatment centres than elsewhere, but the data showed that there were more. Not all candidates realised that the figures given indicated the percentage of people diagnosed with Ebola that died, not the percentage of the population as a whole. As in 1(c) a wide variety of answers was accepted. Some of the answers related to Ebola having a high mortality rate generally, but to score three marks it was necessary to find reasons for treatment centres in particular having high rates of death. One suggestion commonly given but not accepted was that patients became infected after arrival at treatment centres – this would not necessarily give a high fatality rate or percentage and also uninfected people are unlikely to be brought to treatment centres. Some students thought that the more infected people a patient came into contact with, the more infected they would be. This ignores the potential for the Ebola virus to multiply exponentially once inside a patient. Material shortages were only accepted as a reason if this was combined with the idea that treatment centres were swamped with patients.

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’.

This was generally very well answered, with candidates correctly concluding that the drug had potential as a treatment because at a high enough dose it reduced the number of viruses without harming a significant number of cells.

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’.

Vaccination is a major focus on 11.1 of the programme so it was perhaps surprising that answers here were not better. Given the current outbreaks of measles and other diseases that can be prevented by vaccination, this topic should be given greater prominence in some schools. There were a few impressive answers giving the details of the steps that lead up to production of antibodies against a specific pathogen, but less than a quarter of candidates scored all three marks. There were many misconceptions. The terms ‘resistant’ and ‘immune’ have different meanings in biology, which should be carefully distinguished. Some candidates think that a vaccine contains a small amount of the pathogen. Would those candidates be happy to be infected with Ebola viruses as long as it was only a few? There was too much talk of cells ‘remembering’ the antigen or the virus. Memory cell is perhaps an unfortunate term. They are only memory cells in the sense that if an antigen binds to the antibodies they display, after cell multiplication more of those antibodies are produced and they will bind to the same antigens on the surface of an invading pathogen. This is just a series of molecular processes, not true memory. 

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’.

This was a third question where a very wide range of answers were accepted. Even so, not all candidates scored both marks. The commonest weakness was vague answers such as “shortage of resources”. The best answers gave common-sense reasons for special difficulties in controlling an epidemic in the population of a remote rural region.