8. Herpes Simplex Type 1
The herpes simplex virus type 1 (HSV-1) is the culprit for most cold sores (also known as fever blisters). Genital herpes, typically caused by the lesser common herpes simplex virus type 2 (HSV-2), can also cause cold sores. HSV-1 infects most people as children and adolescents. Once infected, the virus remains in the system for a lifetime. The sores can pop up whenever the body is under stress or when the immune system is low. Unfortunately, however, a person can be infectious at any time, with or without the presence of sores.
Though most commonly transmitted during sex, syphilis can also spread through kissing. Syphilis can cause round sores within the mouth, which can transmit the virus. Fortunately, unlike herpes, syphilis can be treated through antibiotics and doesn’t have to be a lifelong disease.
Meningitis is an inflammation of the membrane around the brain and spinal cord and can spread through viral and bacterial infections. Of the two, viral meningitis is less severe and typically goes away without the need for medications or medical follow-up. On the other hand, bacterial meningitis may cause a fever, stiff neck, headache, and nausea. In rare cases, bacterial meningitis may require hospitalization.