Sexually transmitted infections Human Biology Sexually transmitted infections

Keywords & definition Sexually transmitted infections (STI’s) are the infections that are contracted through sexual intercourse or other intimate sexual contact (eg. oral sex). Bacterial STI’s Syphilis Gonorrhea Chlamydia Viral STI’s Genital herpes Genital warts Parasitic STI’s Pubic lice

Pathogens Pathogen STI Viruses genital herpes, genital warts Bacteria The pathogens responsible for STIs include: Pathogen STI Viruses genital herpes, genital warts Bacteria gonorrhea, syphilis, chlamydia Protozoa trichomoniasis Parasites pubic lice

Syphilis Treponema pallidum causes syphilis Chancres resulting from syphilis US Gov-HHS Treponema pallidum causes syphilis

Syphilis - symptoms Syphilis, if untreated, passes through several stages that occur over many years. 1st stage – a sore or chancre appears near site of infection. 2nd stage – rash & prolonged flu-like symptoms before entering long, silent period (often several years). 3rd stage – virus eventually attacks bones, heart & nervous system often leading to insanity & death.

Gonorrhea Bacteria responsible for gonorrhea Newborn baby with gonococcal ophthalmia Gonococcal lesion Bacteria responsible for gonorrhea

Gonorrhea - symptoms Males In 20% of cases there are no symptoms. Remainder suffer discharge of pus from penis and experience pain urinating. Females 10-15% experience symptoms similar to those of men. Majority have no symptoms but all may suffer serious health problems such as pelvic inflammatory disease and infertility.

Herpes Cold sores resulting from the Herpes simplex virus

Genital herpes Genital herpes is usually caused by the Herpes virus Symptoms include painful blistering around the genitalia. Active sores are usually the source of infection. Herpes sores on the lips/mouth will easily transmit the virus to the genital area during oral sex Genital herpes is usually caused by the Herpes virus Some people experience a single episode of herpes – in others it is recurrent.

Herpes infections in newborn babies Mothers who are infected with herpes in the last trimester of a pregnancy are at risk of infecting their baby during birth. More than 40% of newborn babies infected with herpes die or have severe brain damage. A Caesarean section is generally performed if the mother is suspected of having a herpes infection.

Genital warts Genital warts are caused by the human papilloma virus (HPV). Warts generally appear around the external genitalia, though they can also be internal (especially in women). The papilloma virus is responsible for 70% of the cases of cervical cancer in women. The human papilloma virus

Prevention of transmission The use of a male condom during sexual activity may prevent the transmission of pathogens. The use of condoms is 85% effective in preventing pregnancy, so therefore also only 85% effective in preventing the transmission of STI’s Open sores anywhere on the genital area that come into contact will spread the disease

The HPV vaccine A vaccine is now available to combat several strains of HPV. The vaccine is most effective when it is given to females before they first have sexual intercourse. In Australia the National Immunisation Program offers free HPV vaccine to females aged 12 to 26 years. This vaccine will not prevent all HPV infections

Treatment of STI’s Syphilis, gonorrhea & chlamydia Can usually be treated with antibiotics, though antibiotic resistant strains of the pathogens are appearing. Genital herpes No cure, treatment of symptoms only Genital warts HPV vaccine will prevent infections of some strains Warts can be removed using laser treatment or anti-wart ointment