Urethritis is an infection of the urethra and cystitis is an infection of the bladder. Pathogens causing urethritis or cystitis can gain access to the ureter, and from here organisms can travel upwards into the kidneys to cause nephritis (infection of the kidney). Nephritis usually presents with pain in the flanks of the body and a fever above 38.3°C and can occasionally result in septic shock. Usually, the symptoms resolve themselves, and there is no damage to kidney function. In 20–50% of pregnant women, however, the infection causes premature birth. Some people develop chronic nephritis without ever showing any symptoms of a UTI.
Primary syphilis is associated with the appearance of the primary syphilitic lesion, which is a papule that evolves into an ulcer after about 3 weeks. The ulcer remains painless and is referred to as a chancre. Two to eight weeks after the chancre disappears, secondary syphilis (also known as disseminated syphilis) develops. It is characterized by generalized lymphadenopathy and the appearance of a symmetric skin rash on the face, trunk, and extremities accompanied by fever and malaise. The lesions of this rash are extremely infectious but can resolve after many weeks to cause latent syphilis, a stage that can last for years. There are no clinical signs or symptoms, but the infection is continuing. About one-third of untreated patients go on to develop tertiary syphilis. Signs and symptoms can appear as soon as five years after the initial infection but are usually not seen for 15–20 years. Tertiary syphilis can spread to the cardiovascular system (cardiovascular syphilis) or to the nervous system (neurosyphilis). During this process gummas appear. These are localized granulomatous lesions seen in the skin, bones, joints, and internal organs. Neurosyphilis is characterized by a mixture of meningovascular and degenerative changes in the parenchymal tissue, changes that can occur in any area of the body. The most common symptoms of neurosyphilis are chronic meningitis, fever, headache, and increased numbers of cells and protein in the cerebrospinal fluid. There can also be mental impairment including memory loss and hallucinations. Congenital syphilis is passed from mother to fetus after the fourth month of pregnancy and can result in changes to the entire skeletal structure of the newborn, anemia, thrombocytopenia, and liver failure.
There are two distinct epidemiological and antigenic types of herpes simplex virus (HSV), HSV type 1 and HSV type 2. These are DNA viruses with linear double-stranded DNA molecules, and the two types share many of the same antigens and have 50% homology in their genomes. HSV-1 is described as an above-the-waist virus because it causes cold sores in the area of the mouth, and HSV-2 is called a below-the-waist virus because it causes the infection known as genital herpes. HSV-1 can also cause genital herpes but on a much smaller scale than HSV-2.