How do they make susceptible to communicable diseases?

Individuals can become susceptible to communicable diseases due to various factors, including a weakened immune system, poor nutrition, lack of vaccination, and underlying health conditions. Environmental factors, such as overcrowding and poor sanitation, can also increase exposure to pathogens. Additionally, behaviors such as smoking, excessive alcohol consumption, and inadequate hygiene practices may further compromise immune defenses and elevate the risk of infection.