In the chain of infection (infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, susceptible host), which link is generally considered the easiest to break to prevent the spread of disease?

• A. Mode of transmission (e.g., interrupting spread with hand hygiene and PPE)
• B. Infectious agent (eliminating the pathogen from all sources)
• C. Reservoir (removing all human, animal, and environmental reservoirs)
• D. Susceptible host (eliminating susceptibility in all individuals)

Answer: (A)

Verified step by step guidance

1. Understand the chain of infection, which consists of six links: infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host.
2. Recognize that breaking any one of these links can stop the spread of disease, but some links are more practical to target than others.
3. Consider the feasibility of interrupting each link: eliminating the infectious agent or reservoirs completely is often very difficult, and eliminating susceptibility in all individuals (e.g., through immunity) is not always immediately achievable.
4. Focus on the mode of transmission, which involves how the pathogen moves from one host to another, such as through direct contact, droplets, or contaminated surfaces.
5. Identify that interrupting the mode of transmission is generally the easiest and most effective link to break, using measures like hand hygiene, personal protective equipment (PPE), and environmental cleaning to prevent the spread of disease.