24 9 Ebola virus disease (EVD) is a rare and deadly disease most commonly found in Africa. Following a severe outbreak in 2014, in which 11 000 people died, work has been underway to develop a vaccine. The diagram shows the structure of an Ebola virus. RNA strand capsid glycoprotein { (a) Compare and contrast the structure of Ebola virus with that of the human immunodeficiency virus (HIV). (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 25 Turn over (b) A vaccine has been developed by genetically modifying a virus that infects cattle. In the genetically modified virus, one of the genes was replaced with a gene for a protein found in the Ebola virus. In a trial of 52 volunteers, 48 developed antibodies against the Ebola virus within 14 days of injection. (i) The type of immunity given by this vaccine is (1) A artificial active immunity B artificial passive immunity C natural active immunity D natural passive immunity (ii) Explain the role of T cells in the immunity to the Ebola virus that develops following the use of this vaccine. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 26 (c) The vaccine is still undergoing clinical trials, but was given approval for use in recent Ebola outbreaks. (i) Describe how clinical trials of a vaccine would be conducted. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 27 Turn over (ii) The Ebola vaccine was given to health workers and immediate family of those with the disease. Justify the use of this vaccine, even though the clinical trials had not been completed. 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(Total for Question 9 = 14 marks)