A sexually transmitted disease (STD) is an infection you can get by having sex. Some STIs (such as gonorrhea and Chlamydia) infect your sexual and reproductive organs. Others (HIV, hepatitis B, syphilis) cause general body infections.
An STI is spread during sexual activity. It is spread during vaginal, anal and oral sex. Some STIs (HIV and hepatitis B) are also spread by contact with infected blood. STIs are not normally spread by digital sex (fingering); however, unclean hands or uncut nails can cause genital problems.
Most STI germs need to live in warm, moist areas. That's why they infect the mouth, rectum and sex organs (vagina, vulva, penis and testes).
Most STIs can be cured if you seek treatment. Sometimes you can have an STI with no signs or symptoms. Other times, the symptoms go away on their own. Either way, you still have the STI until you get treated. Most STIs can be treated with antibiotics. Some STIs cannot be cured.

HIV

HIV -- the human immunodeficiency virus - is a virus that kills your body’s "CD4 cells." CD4 cells (also called T-helper cells) help your body fight off infection and disease. HIV can be passed from person to person if someone with HIV infection has sex with or shares drug injection needles with another person. It also can be passed from a mother to her baby when she is pregnant, when she delivers the baby, or if she breast-feeds her baby.
AIDS -- the acquired immunodeficiency syndrome - is a disease you get when HIV destroys your body’s immune system. Normally, your immune system helps you fight off illness. When your immune system fails you can become very sick and can die from an illness as common as the flu.
It is important to remember that AIDS is not synonymous with HIV. AIDS results from specific damage to the immune system, and can actually be triggered by many different infections or diseases, one of which is HIV.

HSV

Genital herpes is a sexually transmitted disease (STD) caused by the herpes simplex viruses type 1 (HSV-1) and type 2 (HSV-2). Most genital herpes is caused by HSV-2. Most individuals have no or only minimal signs or symptoms from HSV-1 or HSV-2 infection.

HSV-1 and HSV-2 can be found in and released from the sores that the viruses cause, but they also are released between outbreaks from skin that does not appear to be broken or to have a sore. Generally, a person can only get HSV-2 infection during sexual contact with someone who has a genital HSV-2 infection. Transmission can occur from an infected partner who does not have a visible sore and may not know that he or she is infected.

HSV-1 can cause genital herpes, but it more commonly causes infections of the mouth and lips, so-called "fever blisters." HSV-1 infection of the genitals can be caused by oral-genital or genital-genital contact with a person who has HSV-1 infection.

There is no treatment that can cure herpes, but antiviral medications can shorten and prevent outbreaks during the period of time the person takes the medication.

VDRL

The VDRL test is a screening test for syphilis. It measures substances, called antibodies, that can be produced by Treponema pallidum, the bacteria that causes syphilis.

Syphilis is a sexually transmitted disease (STD) and has often been called "the great imitator" because so many of the signs and symptoms are indistinguishable from those of other diseases.

Syphilis is passed from person to person through direct contact with a syphilis sore. Sores occur mainly on the external genitals, vagina, anus, or in the rectum. Sores also can occur on the lips and in the mouth. Transmission of the organism occurs during vaginal, anal, or oral sex. Pregnant women with the disease can pass it to the babies they are carrying.

Syphilis cannot be spread through contact with toilet seats, doorknobs, swimming pools, hot tubs, bathtubs, shared clothing, or eating utensils.

Genital sores (chancres) caused by syphilis make it easier to transmit and acquire HIV infection sexually. There is an estimated 2- to 5-fold increased risk of acquiring HIV infection when syphilis is present.

Syphilis is easy to cure in its early stages. A single injection of penicillin, an antibiotic, will cure a person who has had syphilis for less than a year. Additional doses are needed to treat someone who has had syphilis for longer than a year.

Because effective treatment is available, it is important that persons be screened for syphilis on an on-going basis if their sexual behaviors put them at risk for STDs.

TPHA

The Syphilis TPHA test is a classic, indirect hemagglutination test used for the detection and titration of antibodies against the causative agent of syphilis,Treponema pallidum.

In the test red blood cells (erythrocytes) are sensitized with antigens from T. pallidum. The erythrocytes will then aggregate together to form distinctive patterns on the surface of a microplate wells when exposed to syphilitic serum.

Chlamydia

Chlamydia is the number one sexually transmitted disease in the United States. Chlamydia is caused by the bacterium, Chlamydia trachomatis, which can damage a woman's reproductive organs. Even though symptoms of chlamydia are usually mild or absent, serious complications that cause irreversible damage, including infertility, can occur "silently" before a woman ever recognizes a problem. Chlamydia also can cause discharge from the penis of an infected man.

Chlamydia can be transmitted during vaginal, anal, or oral sex. Chlamydia can also be passed from an infected mother to her baby during vaginal childbirth.

Any sexually active person can be infected with chlamydia. The greater the number of sex partners, the greater the risk of infection. Because the cervix (opening to the uterus) of teenage girls and young women is not fully matured, they are at particularly high risk for infection if sexually active. Since chlamydia can be transmitted by oral or anal sex, men who have sex with men are also at risk for chlamydial infection.

To help prevent the serious consequences of chlamydia, screening at least annually for chlamydia is recommended for all sexually active women age 25 years and younger.