What is a communicable disease chain? what steps can a nurse can take to break a link within the communicable disease chain?

A diseases may be classified as either communicable or non-communicable. Communicable diseases are caused by pathogens who inhabit a host, man (I'm not saying man is the only host or man is necessarily the final host; there could be many host) who in turn passes the disease to another. Pathogens are viral, bacterial, parasitic and fungal. There are several stages before the pathogen metamorphoses into a full-blown disease. The stages in which several events happen builds up before the pathogen affects the final host is called a communicable disease chain. There are six stages ( Pathogen, reservoir, portal of ext, mode of transmission, portal of entry and susceptible host) in the communicable disease chain but the step a nurse shouod take is 1. Destroy the second link (Reservoir) by thoroughly sanitizing the environment. Obviously, this is where the Pathogens live. If the reservoir is taken care of; there's no way they could infect the host.

The answer is a if u read the definition it makes sense

A- a reduction in biodiversity