Final answer:
Influenza, also known as the flu, is the potentially life-threatening viral infection that starts with flu-like symptoms, caused by the influenza virus, and can lead to serious health implications including widespread epidemics and pandemics.
Step-by-step explanation:
The potentially life-threatening viral infection that commonly starts with flulike symptoms is influenza, also known as the flu. Influenza is caused by the influenza virus, including types A and B, and primarily affects the respiratory system. This contagious illness exhibits initial symptoms like fever, chills, and body aches, before progressing to cold-like symptoms.
Influenza spreads globally in seasonal epidemics and can sometimes become pandemic, affecting large regions or worldwide. It is responsible for a large number of hospitalizations and deaths annually. Due to its rapid mutation through antigenic drift and antigenic shift, it remains a significant health threat, and as a result, new influenza vaccines are developed every year.