The main throat infections related to oral sex are the sexually transmitted viruses and bacteria that you mentioned – Chlamydia, Gonorrhea, HPV, herpes and syphilis. Some throat cancers are related to HPV, which is a sexually transmitted virus.
It is possible to get infections from oral anal sexual contact. Some bacteria found in the bowel that can be passed through oral anal contact include Shigella, Campylobacter and Salmonella, They can cause diarrhea, bloody diarrhea and stomach cramps, although they do not always cause disease. Hepatitis A is a virus that can be passed through oral anal contact. Vaccinations for Hepatitis A are harm reduction approach if you are having oral anal sex. Hand washing to prevent the spread of bowel bacteria or viruses from hands to mouth is always a good idea.
Oral sex is a harm reduction approach for HIV. Another harm reduction approach that some people use is withdrawal prior to ejaculation. It may not help with skin-to-skin STIs such as herpes, HPV or syphilis, but it might help with gonorrhea, chlamydia and HIV.
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