Final answer:
Infections can occur without symptoms and can be local or systemic. Primary infections can lead to secondary infections, especially when the immune system is weakened. Some infections can be chronic or latent.
Step-by-step explanation:
Infections can occur even if the patient is not presenting symptoms because some diseases may be asymptomatic or subclinical, meaning they do not present any noticeable signs or symptoms. For example, individuals infected with herpes simplex virus can remain asymptomatic and unaware that they have been infected.
Bacteria can enter the body through breaches in the skin barrier or mucosa, such as insect bites or small wounds. This can lead to transient bacteremia, which is often below the threshold of detection. In severe cases, bacterial infections can result in clinical signs and symptoms like septicemia and septic shock.
Systemic infections occur when an infection spreads throughout the body. Primary infections can also lead to secondary infections by other pathogens, especially when the immune system is compromised. Some infections can be chronic or latent, meaning they persist in the body without causing noticeable symptoms.