Question 1: Malaria is caused by Plasmodium parasites transmitted through the bites of infected female Anopheles mosquitoes. The parasite undergoes a complex lifecycle involving human and mosquito hosts.

Answer: Malaria is caused by Plasmodium parasites transmitted by infected female Anopheles mosquitoes, involving a lifecycle that alternates between human and mosquito hosts.

Question 1: Define the term 'vector' in the context of malaria.

Answer: A vector is an organism, such as a mosquito, that transmits a pathogen from one host to another.

Question 2: Explain why the Anopheles mosquito is considered a critical factor in the spread of malaria.

Answer: The Anopheles mosquito is considered a critical factor because it acts as the primary vector transmitting Plasmodium parasites from infected individuals to healthy ones during blood meals, facilitating the spread of malaria.

Question 1: Calculate the basic reproduction number (R₀) for a malaria outbreak where each infected person infects an average of 4 others, with a transmission probability of 0.3 per bite, and an average of 10 bites per mosquito per day over a 30-day infectious period.

Answer: R₀ = (Number of bites per mosquito per day) × (Transmission probability per bite) × (Duration of infectiousness in days) = 10 × 0.3 × 30 = 90

Question 2: If a region has an initial population of 10,000 people and a malaria prevalence rate of 15%, how many individuals are currently infected?

Answer: Infected individuals = 10,000 × 0.15 = 1,500

Question 1: Describe a safe laboratory method for studying the lifecycle of Plasmodium without risk of infection.

Answer: Using in vitro cultures in a controlled lab environment with proper sterilisation and safety protocols, avoiding exposure to live parasites or infected vectors.

Question 2: Identify two variables that should be controlled in an experiment testing the effectiveness of a malaria vaccine.

Answer: Variables to control include the age and health status of participants, and the dosage of the vaccine administered.

Question 1: In a study, 200 individuals in a malaria-endemic area were tested, and 30% were found to be currently infected. Over a year, the infection rate decreased to 10% after implementation of bed net distribution and insecticide spraying. Explain the significance of these results.

Answer: The decrease from 30% to 10% suggests that the interventions (bed nets and insecticide spraying) were effective in reducing malaria transmission, indicating successful control measures.

Question 1: Describe the lifecycle stages of Plasmodium within the human host and the mosquito vector, highlighting where each stage occurs.

Answer: The lifecycle begins when an infected mosquito injects sporozoites into the human bloodstream. These travel to the liver, where they mature into schizonts. The schizonts rupture, releasing merozoites that infect red blood cells, leading to symptoms. Some merozoites develop into gametocytes, which are taken up by another mosquito during a blood meal. Inside the mosquito, gametocytes mature into gametes, fuse to form zygotes, develop into ookinetes, and then into oocysts on the mosquito's gut wall. The oocysts release sporozoites that migrate to the mosquito's salivary glands, ready to infect another human.

Question 1: Discuss how gene editing technologies, such as CRISPR, are being explored to combat malaria.

Answer: Gene editing technologies like CRISPR are being used to modify mosquito genomes to reduce their ability to transmit Plasmodium parasites, or to reduce mosquito populations, thereby decreasing malaria transmission.

Question 2: Explain how the development of malaria vaccines impacts global health strategies.

Answer: Malaria vaccines provide a powerful tool to reduce disease incidence, especially in endemic regions, complementing vector control measures and contributing to the goal of malaria eradication, thus improving global health outcomes.