Many<unk> s are (more easily) transmitted through the mucous membranes of the penis, vulva, rectum, urinary tract and (less often—depending on type of infection) the mouth, throat, respiratory tract and eyes. 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. The amount of contact with infective sources which causes infection varies with each pathogen but in all cases, a disease may result from even light contact from fluid carriers like venereal fluids onto a mucous membrane. Some<unk> s such as HIV can be transmitted from mother to child either during pregnancy or breastfeeding. Healthcare professionals suggest safer sex, such as the use of condoms, as a reliable way of decreasing the risk of contracting<unk>  transmitted diseases during sexual activity, but safer sex cannot be considered to provide complete protection from an<unk> . The transfer of and exposure to bodily fluids, such as blood transfusions and other blood products, sharing injection needles, needle-stick injuries (when medical staff are inadvertently jabbed or pricked with needles during medical procedures), sharing tattoo needles, and childbirth are other avenues of transmission. These different means put certain groups, such as medical workers, and haemophiliacs and drug users, particularly at risk. It is possible to be an asymptomatic carrier of<unk>  transmitted diseases. In particular,<unk>  transmitted diseases in women often cause the serious condition of pelvic inflammatory disease.
Sexually transmitted infection
Interstitial cystitis
Vertically transmitted infection
Neurodegenerative disease
Blood-borne disease
Environmental disease
Secondary trauma
Psychogenic disease