Many of our friends are showing considerable fear of these diseases, both in outpatient clinics and in real life, or in the now very hot Internet healthcare. There is no need to worry so much, as you will not generally contract these diseases from exposure to them. Some friends even to the point of needing the intervention of a psychiatrist, where it is necessary to remind the majority of friends of the Internet is the need to figure out what the transmission of these diseases. HIV, syphilis spirochetes, hepatitis B virus, hepatitis C virus they have a surprising commonality in the transmission route, that is, mainly through blood transmission, sexual transmission and vertical transmission from mother to child. Like the general life contact are not infectious these diseases. Friends first understand what behavior belongs to high-risk behavior: 1, input carrying the above pathogens or contaminated blood, plasma and other products (the current detection is extremely strict, the probability is quite low), the sharing of intravenous needles used for drug use (multiple people, repeated use belongs to the high-risk, once in a while is not necessarily infected). 2, sexual contact transmission, substantial sexual activity (must reach the possibility of exchange of bodily fluids between the two sides, such as ejaculation, oral sex after ejaculation, etc.), homosexual sex, especially gay sex. Sexually active people, people with many sexual partners, and sexually promiscuous people belong to the high-risk group, but the risk is greatly reduced for those who have taken safety measures (there is some risk if the process is broken or slipped). If the hand touches the genitals and other possible ways of infection chances can be ignored. Sexual transmission is currently the predominant mode of transmission of these diseases. There may be some symptoms, not necessarily infected with the above diseases, may be other STDs, the need for dermatological venereal disease department consultation. 3, vertical transmission from mother to child, including in pregnancy, during childbirth, postpartum, and ultimately, blood transmission or the exchange of bodily fluids between mother and child exists. Currently these diseases are artificially blocked before and after childbirth (infection rates are greatly reduced). Other rare routes of transmission are via broken skin, shared toothbrushes and scrapers, and other blood-sucking insects that are currently inconclusive.