Final answer:
A cough can indicate exposure to tuberculosis, which is characterized by a range of symptoms including fatigue and a low-grade fever. The Mantoux tuberculin skin test is used to diagnose TB exposure by observing the immune response to injected bacterial proteins.
Step-by-step explanation:
The presence of a cough can indicate that a client has been exposed to tuberculosis (TB). TB is an infectious disease caused by the bacterium Mycobacterium tuberculosis. In addition to a cough, other common symptoms of TB include fatigue, night sweats, loss of appetite, and a low-grade fever. Someone who has been exposed to TB may initially experience symptoms that are similar to other illnesses, such as the flu or a cold, but TB symptoms typically persist and may worsen over time.
When a healthcare professional suspects a person has been exposed to TB, a diagnostic skin test called the Mantoux tuberculin skin test is often performed. This test involves injecting a small amount of bacterial proteins into the skin and checking for a reaction, such as a raised red area, a couple of days later. A positive reaction, known as induration, suggests that the patient has been exposed to the TB bacteria and has developed a cellular immune response against it.