9. Outline three (3 ) types of disease agents( 3 marks) 10. Explain secondary level of disease prevention. (3 marks) 11. Explain the term "Distribution of health-related events' as used in epidemiology. (2 marks) 12. Describe the principles of communicable diseases prevention. (9 marks) 13. Describe the pathogenesis stage of the natural history of disease . (5 marks) 14. Outline four (4)analytical epidemiological study designs. (4marks)

9. Three types of disease agents are:<br /> - Bacteria: Single-celled microorganisms that can cause infections.<br /> - Viruses: Microscopic infectious agents that replicate inside host cells.<br /> - Fungi: Organisms that can cause infections, particularly in immunocompromised individuals.<br /><br />10. The secondary level of disease prevention involves early detection and prompt intervention to halt the progression of a disease. This includes screening programs, early diagnosis, and treatment to prevent complications and improve outcomes.<br /><br />11. The term "Distribution of health-related events" in epidemiology refers to the analysis of the patterns, frequency, and occurrence of health-related events in a population. It examines factors such as the who, what, when, and where of health events to identify patterns and potential causes.<br /><br />12. The principles of communicable diseases prevention include:<br /> - Identification and isolation of infected individuals to prevent transmission.<br /> - Implementation of vaccination programs to induce immunity.<br /> - Promotion of personal hygiene and sanitation practices.<br /> - Monitoring and controlling vectors and reservoirs of infection.<br /> - Providing education and awareness to the community.<br /><br />13. The pathogenesis stage of the natural history of disease involves the development and progression of the disease process. It includes the initial interaction between the pathogen and the host, invasion and multiplication of the pathogen, tissue damage, and the host's response to the infection.<br /><br />14. Four analytical epidemiological study designs are:<br /> - Cohort studies: Observational studies that follow a group of individuals over time to compare the occurrence of outcomes.<br /> - Case-control studies: Studies that compare individuals with a particular condition (cases) to those without the condition (controls).<br /> - Cross-sectional studies: Studies that assess the prevalence of a condition at a single point in time.<br /> - Experimental studies: Studies where the researcher manipulates an independent variable to observe its effect on a dependent variable.