Many infectious diseases are multifactorial, meaning they are caused by the interaction of several factors inside and outside the person. For an infection to occur, three key conditions, known as the epidemiological triad of disease must be met. 

• What is the epidemiological triad? Describe. 
• What are pathogens and how do pathogens gain entry? 
• Explain how your immune system protects you, what factors diminish its effectiveness and what can you do to boost its effectiveness. 
• What can you do to reduce your risk of infectious disease?

Please use book attached book as one of the reference.