STDs

I'm sure you've all heard of STDs, or sexually transmitted diseases. They're also known as STIs, or sexually transmitted infections. In this post, I'm going to briefly outline a few of the more common ones. STIs can generally be prevented using similar means- have safe sex, don't share needles, and don't allow any cuts or scratches you may have to come into contact with human blood. (Why you would want to is beyond me, but there you go.)

Gonorrhoea

Caused by: A bacteria called Neisseria gonorrhoea
Areas affected: The mucous membranes of the excretory and reproductive systems, the rectum, occasionally the eyes. If untreated, can spread to other areas. In males, infection can spread to the testes, joints or to the heart or eyes. In females, infection can spread to the oviducts and abdominal membranes.
Incubation period (time before symptoms show): 2-10 days
Symptoms in males: Inflammation in the urethra causes a burning feeling in the penis, extreme pain when passing urine and a yellow discharge of pus from the penis. If untreated, the urethra can become permanently constricted, making urination difficult. If the infection spreads to the testes, sterility can occur; if it spread to the joints, a type of arthritis can occur.
Symptoms in females: Symptoms may go unrecognised in females, but this doesn't make them any less dangerous. Some pus may be produced, but may be misinterpreted as normal vaginal discharge. If the oviducts are infected, permanent blockage and sterility may occur.
Effects on unborn babies: Babies may be infected during birth. The bacteria may enter the baby's eyes, causing an acute eye infection. As a precautionary measure, special eye drops are given to all babies immediately after birth.
Detection: Smear tests, urine tests
Treatment: Treatment involves antibiotics, which normally results in an easy and effective cure. There are, however, some strains of gonococcus that are resistant to antibiotics.

Syphilis

Caused by: A bacteria called Treponema pallidum
Areas affected: Affects many different areas throughout the three phases of the disease.
Incubation period: 10 days to 10 weeks (normally 2-4 weeks)
Symptoms in the primary stage: Small sores called chancres (pronounced "shankers") appear, mainly on the sex organs but can also occur on other parts of the body such as on the lip, finger or eyelid. Some are too small to be noticed, but they can be up to 1cm in diameter. They are normally painless and heal in 3-8 weeks, which can provide a false sense of security.
Symptoms in the secondary stage: The secondary stage occurs up to 12 months after the primary stage (but normally occurs only a few weeks after the primary stage), and lasts for about two years. There are many possible symptoms that can occur, including skin rashes that persist for several weeks, sore or ulcerated mouth or throat, mild fevers and disorders of the bones or eyes.
Symptoms in the tertiary stage: During this stage, many tissues of the body are damaged, although there may not be any symptoms for many years- perhaps not until 5- 40 years later! Hence, this stage is sometimes called the latent (hidden) phase. During this stage, the body may develop an immunity to the bacteria or destroy it, or the bacteria may spread and cause syphilitic heart disease, insanity, blindness, weakening of the blood vessels, physical incapacity, and so on.
Effects on unborn babies: An infected woman may not necessarily spread the disease to the foetus, but if so the foetus can go through all three stages of syphilis before birth, which may result in permanent damage to the heart, nervous system, joints or other organs.
Detection: Blood tests
Treatment: Antibiotics are the usual treatment, but surgery may be necessary in the later stages.

HIV and AIDS (Human Immunodeficiency Virus and Acquired Immune Deficiency Syndrome)

Caused by: The human immunodeficiency virus :) It is a retrovirus, which means that it contains an RNA core instead of a DNA core. It cannot reproduce itself.
Areas affected: The immune system. It infects white blood cells known as T-lymphocytes, and uses them to produce more of the virus. Destruction of the T-lymphocytes then leaves the body open to infections.
Incubation period: Some people develop an illness, called seroconversion illness, within two weeks of exposure. A period of up to 10 years without symptoms then follows.
Symptoms of Category A infection: Category A includes the aforementioned seroconversion illness, which has similar symptoms to glandular fever: lack of energy, fevers, headaches, dry cough, swollen lymph nodes and pain in muscles and joints. The person recovers 3-14 days later, after which they experience no symptoms for up to 10 years. Although they may not be showing symptoms during this period, they are highly contagious.
Symptoms of Category B infection: Category B generally occurs several months to several years after infection. The T-lymphocyte count drops considerably and an illness known as persistent generalised lymphadenopathy (or "AIDS-related complex') develops, resulting in symptoms such as diarrhoea, fatigue, fever, sudden weight loss, a dry cough, unexplained bleeding, shortness of breath and swelling in the armpits, neck and groin. Signs of nervous system impairment, such as loss of memory, inability to think clearly and loss of judgement, are also quite common.
Symptoms of Category C infection: People in this category are extremely ill, and in most cases have developed AIDS and/or have serious illnesses related to HIV. Illnesses contributing to this condition include pneumonia, cancer and brain disorders.
Detection: As the body produces antibodies in response to HIV infection, antibody tests can be done. However, it takes around 2-6 weeks for antibodies to build up to the point where they can be detected. Other tests can measure viral load, which describes the amount of HIV in the blood and gives an indication of the activity of the virus.
Treatment: As yet there is no cure. Some medications can inhibit the reproductive cycle of the virus, which suppresses the progression of the disease, but these medications cannot get rid of the infection completely. Even in cases where the viral load is too low to be detected, the virus remains lurking in tissues like the spleen and lymph nodes, so therapy has to be continued indefinitely.

Hepatitis B (HBV)

Caused by: A DNA virus
Areas affected: The liver ("hepa" = liver, "-itis" = "inflammation"). The virus is carried in all bodily fluids, and can thus be spread through sexual contact or through sharing infected items such as needles and syringes. Mothers may also pass it on to their babies at birth, which is why babies are vaccinated against Hep B at birth.
Symptoms: Flu-like symptoms, including fatigue, fever, headache, nausea, vomiting and muscle aches. Another symptom is jaundice, which is yellowing of the skin.
Treatment: In severe cases, a liver transplant might be necessary.
Prevention: There is a vaccine available for hepatitis B. (There's also one for hepatitis A, for that matter.) If I remember correctly, immunity from hepatitis B also gives you immunity from hepatitis D (since the Hep D virus relies on the existence of the Hep B virus)- bonus!

Chlamydia

Caused by: A bacteria called chylamydia trachomatis
Areas affected: Lots of places
Symptoms in men: An infection of the urethra, known as non-specific urethritis (NSU) can develop. (The Chlamydia bacteria is, however, not the only organism that can cause NSU.) This causes symptoms such as yellow discharge from the penis and a burning sensation when passing urine. If the infection is not treated, it can spread to the epididymis, causing epididymitis, which causes pain and swelling of the epididymis. If both testes are infected, infertility can result, though this is very rare.
Symptoms in women: Many women have no symptoms, which can lead to treatment being delayed until too late. Some women show symptoms of pelvic inflammatory disease (PID). This is inflammation of organs in the pelvic region such as the uterus and uterine tubes, which can lead to blockage of the uterine tubes by scar tissue, which can then lead to infertility or ectopic pregnancies. If untreated, the disease can lead to infertility, eye infection and arthritis.
Effects on unborn babies: There is a 70% chance that a pregnant woman will pass chlamydia on to the foetus. The baby may then suffer from conjunctivitis (inflammation of the mucous mebrane covering the eyeball), nose and throat infections, or pneumonia.
Detection: In women, a swab can be taken from the cervix for analysis. Urine tests can also be used.
Treatment: Antibiotics are usually used, though the bacteria may never be completely eliminated from the body.
Fun fact: Apparently koalas are dying of chlamydia...

Genital Herpes

Caused by: The Herpes simplex virus type 2 (HSV2). (HSV1, in case you were wondering, is the virus that causes "cold sores" on the lip.)
Areas affected: The genital organs- the penis of males and the labia and vagina of females.
Symptoms: Blisters are formed on the genital organs. They eventually heal, but some of the virus passes into the nervous system, where it remains for life. The virus can then pop up to HAUNT YOU FOR THE REST OF YOUR LIFE!!! (sorry, just had to be overly dramatic in there somewhere.)
Effects on unborn babies: Children born to infected mothers may suffer serious malformations and life-threatening diseases. Caesarian sections may be used to prevent further complications.
Treatment: There is no cure, but medication and saline dressings may be used to reduce the pain and clean up the blisters.

Genital Warts

Caused by: The human papillomavirus (HPV)
Areas affected: Usually the genital organs, but can also affect the anus or throat.
Effects on unborn babies: The baby can be infected while being born.
Prevention: Vaccines are available against some of the strains of HPV.

Pubic Lice and Scabies

Caused by: The pubic louse is an insect called Phythirus pubis, and scabies is caused by a mite called Sarcoptes scabei. Pubic lice and scabies can be transmitted by sexual contact, but this is not necessary- prolonged, warm, close contact is enough to spread both.
Areas affected: Pubic lice is normally only found in the pubic and anal areas, but may also be found in chest and armpit hair; scabies is found in the genital region, wrists and finger webs.
Symptoms: Extreme itchiness, especially at night.

Trichomoniasis

Caused by: A protozoan called Trichomonas vaginalis
Areas affected: The mucous membranes of the vagina in women, the urethra in men
Symptoms: Women may experience great discomfort and symptoms such as severe itching; men, however, may be asymptomatic but can transmit the infection to females.
Treatment: Antibiotics.

Aaaaaaaaaaaand that concludes my last post about reproduction and other related stuff! Yay! Be safe, everyone!