Thus, one may presume that, if a person is infected with an STI, e.g., chlamydia, gonorrhea, genital herpes, it was transmitted to him/her by means of sexual contact.The English language has short words for two of the most common: "pox" (syphilis) and "the clap" (gonorrhea). Pathology:Many STIs are (more easily) transmitted through the mucous membranes of the penis, vulva, and (less often)citation needed the mouth. The visible membrane covering the head of the penis is a mucous membrane, though it produces no mucus (similar to the lips of the mouth). Mucous membranes differ from skin in that they allow certain pathogens into the body.This is one reason that the probability of transmitting many infections is far higher from sex than by more casual means of transmission, such as non-sexual contact—touching, hugging, shaking hands—but it is not the only reason. Although mucous membranes exist in the mouth as in the genitals, many STIs seem to be easier to transmit through oral sex than through deep kissing.

According to this chart , many infections that are easily transmitted from the mouth to the genitals or from the genitals to the mouth, are much harder to transmit from one mouth to another. With HIV, genital fluids happen to contain much more of the pathogen than saliva. Some infections labeled as STIs can be transmitted by direct skin contact. Herpes simplex and HPV are both examples. KSHV, on the other hand, may be transmitted by deep-kissing but also when saliva is used as a sexual lubricant, which is common among gay men engaging in anal intercourse.Depending on the STD, a person may still be able to spread the infection if no signs of disease are present. For example, a person is much more likely to spread herpes infection when blisters are present (STD) than when they are absent (STI). However, a person can spread HIV infection (STI) at any time, even if he/she has not developed symptoms of AIDS (STD).All sexual behaviors that involve contact with another person or the bodily fluids of another person should be considered to contain some risk of transmission of sexually transmitted diseases.

Most attention has focused on controlling HIV, which causes AIDS, but each STD presents a different situation.As may be noted from the name, sexually transmitted diseases are transmitted from one person to another by certain sexual activities rather than being actually caused by those sexual activities. Bacteria, fungi, protozoa or viruses are still the causative agents. It is not possible to catch any sexually transmitted disease from a sexual activity with a person who is not carrying a disease; conversely, a person who has an STD got it from contact (sexual or otherwise) with someone who had it, or his/her bodily fluids. Some STDs such as HIV can be transmitted from mother to child either during pregnancy or breastfeeding.Although the likelihood of transmitting various diseases by various sexual activities varies a great deal, in general, all sexual activities between two (or more) people should be considered as being a two-way route for the transmission of STDs, i.e., "giving" or "receiving" are both risky.

Healthcare professionals suggest safer sex, such as the use of condoms, as the most reliable way of decreasing the risk of contracting sexually transmitted diseases during sexual activity, but safer sex should by no means be considered an absolute safeguard. The transfer of and exposure to bodily fluids, such as blood transfusions and other blood products, sharing injection needles, needle-stick injuries

Sexually Transmitted Disease

A sexually transmitted disease (STD) or venereal disease (VD), is an illness that has a significant probability of transmission between humans or animals by means of sexual contact, including vaginal intercourse, oral sex, and anal sex. Increasingly, the term sexually transmitted infection (STI) is used, as it has a broader range of meaning; a person may be infected, and may potentially infect others, without showing signs of disease. Some STIs can also be transmitted via use of an IV drug needle after its use by an infected person, as well as through childbirth or breastfeeding. Sexually transmitted infections have been well known for hundreds of years. Classification and terminology:Until the 1990s, such afflictions were commonly known as venereal diseases: Veneris is the Latin genitive form of the name Venus, the Roman goddess of love. Social disease was another euphemism.Public health officials originally introduced the term sexually transmitted infection, which clinicians are increasingly using alongside the term sexually transmitted disease in order to distinguish it from the former.

According to Ethiopian Aids Resource Center FAQ - Are sexually transmitted infections (STIs) different from sexually transmitted diseases (STDs)?, "Sometimes the terms STI and STD are used interchangeably. This can be confusing and not always accurate, so it helps first to understand the difference between infection and disease. Infection simply means that a germ — virus, bacteria, or parasite — that can cause disease or sickness is present inside a person’s body. An infected person does not necessarily have any symptoms or signs that the virus or bacteria is actually hurting his or her body; they do not necessarily feel sick. A disease means that the infection is actually causing the infected person to feel sick, or to notice something is wrong. For this reason, the term STI — which refers to infection with any germ that can cause an STD, even if the infected person has no symptoms — is a much broader term than STD." The distinction being made, however, is closer to that between a colonization and an infection, rather than between an infection and a disease.

Specifically, the term STD refers only to infections that are causing symptoms. Because most of the time people do not know that they are infected with an STD until they start showing symptoms of disease, most people use the term STD, even though the term STI is also appropriate in many cases.Moreover, the term sexually transmissible disease is sometimes used since it is less restrictive in consideration of other factors or means of transmission. For instance, meningitis is transmissible by means of sexual contact but is not labeled as an STI because sexual contact is not the primary vector for the pathogens that cause meningitis. This discrepancy is addressed by the probability of infection by means other than sexual contact. In general, an STI is an infection that has a negligible probability of transmission by means other than sexual contact, but has a realistic means of transmission by sexual contact (more sophisticated means — blood transfusion, sharing of hypodermic needles —are not taken into account).