Answer:
The spread of an infection within a community is described as a “chain,” several interconnected steps that describe how a pathogen moves about. Infection control and contact tracing are meant to break the chain, preventing a pathogen from spreading.
Emerging infectious diseases are those whose incidence in humans has increased in the past two decades or are a threat to increase in the near future. These diseases, which can rapidly spread across national boundaries and communities, may challenge the ability of public health systems to prevent and control the spread of the disease, especially in resource-limited countries and regions.
The spread of infection can be described as a chain with six links:
Infectious agent (pathogen)
Reservoir (the normal location of the pathogen)
Portal of exit from the reservoir
Mode of transmission
Portal of entry into a host
Susceptible host
