Question 1: Define Measles and describe its primary mode of transmission.

Answer: Measles is a highly contagious viral disease caused by the Measles virus, transmitted mainly through respiratory droplets when an infected person coughs or sneezes.

Question 2: Explain how the immune system responds when a person is infected with the Measles virus.

Answer: The immune system recognises the virus as foreign, triggers an immune response producing specific antibodies and memory cells, which help in fighting the infection and provide immunity against future infections.

Question 3: What is herd immunity and how does vaccination contribute to it in the context of Measles?

Answer: Herd immunity occurs when a high proportion of the population is immune to a disease, reducing its spread. Vaccination helps achieve herd immunity by protecting the vaccinated individual and reducing transmission within the community.

Question 1: Calculate the percentage decrease in Measles cases if the number of cases drops from 1500 to 300 after a vaccination campaign.

Answer: Percentage decrease = ((1500 - 300) / 1500) × 100 = 80%

Question 2: If a population of 50,000 has a vaccination coverage of 92%, how many individuals are unvaccinated?

Answer: Unvaccinated individuals = 50,000 × (1 - 0.92) = 4,000

Question 1: Describe a basic experimental setup to test the effectiveness of a new Measles vaccine in a laboratory setting.

Answer: The experiment involves dividing a suitable animal model or cell culture into control and experimental groups, administering the vaccine to the experimental group, exposing both groups to the virus, and monitoring infection rates, while maintaining strict safety protocols such as PPE and containment measures.

Question 2: Identify two variables that must be controlled in a Measles vaccine trial.

Answer: Variables include the age of subjects and the dosage of the vaccine.

Question 3: State two safety precautions that should be taken during research involving the Measles virus.

Answer: Use of personal protective equipment (PPE) and conducting experiments in a biosafety level 2 or higher laboratory.

Question 1: In a community of 10,000 people, 8,000 are vaccinated against Measles. During an outbreak, 200 unvaccinated individuals and 50 vaccinated individuals contract the disease. Calculate the attack rate for both groups and interpret the results.

Answer: Attack rate in unvaccinated = (200 / 2000) × 100 = 10%; Attack rate in vaccinated = (50 / 8000) × 100 = 0.625%. The data indicates that unvaccinated individuals are significantly more likely to contract Measles, demonstrating the vaccine's effectiveness.

Question 1: Explain the mechanism by which the Measles virus causes symptoms such as rash and fever. Include in your answer how the immune system responds to the infection.

Answer: The Measles virus infects cells in the respiratory tract and spreads through the bloodstream, causing symptoms like rash and fever as a result of the immune response. The immune system detects viral particles, triggers inflammation, and produces specific antibodies and memory cells, which contribute to recovery and long-term immunity.

Question 1: Discuss how global vaccination programmes have impacted the incidence of Measles worldwide over the past 20 years.

Answer: Global vaccination programmes have significantly reduced Measles cases and outbreaks worldwide, preventing millions of deaths, especially in developing countries, by increasing herd immunity and preventing virus transmission.

Question 2: Describe a potential technological advancement that could improve Measles vaccination delivery or effectiveness.

Answer: Development of thermostable vaccines that do not require cold chain storage could improve vaccination coverage in remote areas, increasing overall effectiveness.