Primary infection has two meanings and can relate either to the first signs that a person/living thing has become infected or to a hierarchy of infections that begin with a single illness. In the second definition, a person with a virus like a cold could get a bacterial infection in the chest such as bronchitis. These could be labeled primary and secondary infections both arising from the original cold. On the other hand, primary infection resulting from first contact with a viral or bacterial source might mean the first noted signs of that infection. These are often identified as specific symptoms.
The first symptoms of an illness or a primary infection are often identified in diseases that continue to live in the body and become chronic. Genital herpes is one of these illnesses. Sores developing on the genitals or surrounding areas usually mark the first infection after exposure, and these may last for several weeks. Other symptoms like headache, achiness, flulike feelings, fever, or swollen glands could also be present, and may not occur as often in subsequent expressions of the disease.
When people get herpes blisters again the condition is called recurrent instead of being named a primary infection. The first response to viral contagion is primary, and all other expressions of the disease are recurrent, showing its chronic nature. Other illnesses that have a primary infection include conditions like HIV/AIDs, other herpes viruses like chicken pox, and some forms of hepatitis. It should be noted with all of these that symptoms arising from initial exposure may be a little different than the way the disease is expressed later on; they are the first immune response to exposure to an infectious agent.
There are many instances where primary and secondary are used to describe an illness that causes multiple infections. These infections are often viral/bacterial in nature. Many people get viruses that weaken the immune system and are likely to result in secondary bacterial infections. The primary infection is thus the original virus, but its ability to predispose people to pick up bacterial infections may mean doctors are on the alert.
With a virus like genital herpes, poor care of the sores may occasionally lead to skin infection or cellulitis. While a doctor wouldn’t treat a herpes infection with antibiotics because it is of viral origin, he might use antibiotics if herpes blisters get infected, to kill the secondary infection. The antibiotics wouldn’t have any effect on the primary infection but they could address a secondary one.
Many flu viruses are prone to causing secondary infections like bronchitis, pneumonia, or sinus and ear infections. Again, antibiotics might be used to address these. Yet they would not get rid of the flu, which is viral. People more prone to secondary infections of this type may have reduced immune systems, and in the medically vulnerable, watching for secondary infections is very important with certain illnesses