Information | STD | HPV
Sexually Transmitted Diseases
Sexually transmitted diseases (STDs) are infectious diseases that are mainly passed from one person to another during sex. Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) are the most common bacteria causing STDs. According to Center for Disease Control and Prevention (CDC), CT is the main cause of STDs.
Chlamydia is a bacteria infection which can be easily treated with antibiotics; however, asymptomatic stage makes hard to diagnose the disease. W ithout any treatments, women can experience infertility, and Pelvic Inflammatory Disease (PID) leading to extrauterine pregnancy. Moreover, if a patient with chlamydia is exposed to HIV (Human Immunodeficiency Virus), the chance of the patient being progressed to AIDS is 3 to 5 times higher than that of a healthy person. As a result, accurate and rapid diagnosis followed by proper treatment is mandatory; especially, if a pregnant woman is not treated accordingly, both a fetus and a mother are at risk of being developed into a life threatening situation.
Gonorrhea is also one of the most prevalent STDs, like chlamydia, and it is the main cause of PID in the US . The main bacterium causing gonorrhea is Neisseria gonorrhoeae, which is non-motile, gram-negative diplococcus propagating either in the reproductive tubes, such as cervical region, uterus, Fallopian tube, or urethra. Gonorrhea can be easily curable as well, but if left untreated, Pelvic Inflammatory Disease (PID) leading to extrauterine pregnancy, tubal infertility, and chronic pelvic pain.
For detecting the major bacteria causing STDs - N. gonorrhoeae and C. trachomatis - bacteria culture and EIA are the most common methods. On the other hand, molecular diagnostics using PCR has been widely utilized due to several advantages over the others. The advantages are following: increased sensitivity due to target DNA amplification, possible utility of variable specimen in one test, and simplicity of acquiring sample from a patient. The biggest advantage, especially, of molecular diagnostics is the fact that early diagnosis is possible because of its rapid turn-around-time (TAT); hence, an adequate antibiotics regimen can be administered to a patient and provide the basis of estimating whether or not full recovery is possible.
STDs generally refer to all diseases transmitted through sexual activity.
STDs are usually caused by sexual activity with an infected individual, possibly via the fingers or mouth. They can also be caused by vertical transmission from the mother to the fetus, and very occasionally by protozoan infection during daily activities such as visits to public bathhouses and sauna parlors.
Classification
- Bacterial infection :
syphilis, gonorrhea, chancroid, nongonococcal urethritis (Chlamydia)
- Viral infection : herpes genitalis (genital herpes), condyloma acuminatum (anogenital
warts)
- Protozoan infection : trichomonas vaginitis, amebic urethritis
- Fungal infection : candida vaginitis
candida vaginitis
1) Syphilis
- Symptoms: Syphilis infection comprises several stages clinically speaking, which are
divided into the incubation, primary syphilis, secondary syphilis, latent syphilis, and late
syphilis stages. Late syphilis is also known as tertiary syphilis, and has appeared as
neurosyphilis, cardiovasculr syphilis, and gumma.
- Congenital syphilis: The pathogen causing syphilis can pass through the placenta at any
time during pregnancy. However, it can pass through the placenta more easily during late
pregnancy and when a pregnant woman has syphilis with a strong infectiousness (primary,
secondary, latent syphilis). Infection with congenital syphilis is accompanied by systemic
malformation (including the heart and bones), and the possibility of premature birth and
infant mortality is usually high.
- Pathogen: Treponema pallidum
Treponema pallidum is a spirochaete which causes syphilis, a chronically infectious
disease. Infection usually occurs through sexual intercourse or a kiss with a syphilitic
patient, and sometimes through vertical transmission from mother to fetus.
2) Chancroid
- Chancroid is characterized by the appearance of a small bump that becomes an ulcer
(bumpy and exudate-covered genital ulcer) after 3~5 days of infection. This ulcer, called
chancroid (soft chancre) in contrast with hard chancre, is a characteristic lesion of the
primary stage of infectious syphilis. Once a soft chancre has appeared, the lymph node
in the region becomes larger and infection is observed.
- Pathogen: Haemophilus ducreyi
This small pathogen causing chancroid is 1~1.5 ㎛ long and 0.6 ㎛ wide. It is not easily
identified due to the difficulty of making a culture, and thus it has been assumed that
significant numbers of patients in the country go undiagnosed because of the difficulty
of detecting the pathogens.
3) Herpes
- The infection develops following direct skin contact, and basically invades through
relatively more fragile mucosal regions such as the oral mucosa or urethral mucosa rather
than through the skin, but the disease can be transmitted via the skin if the skin has been
weakened by infection or wounds. The inflicted regions are usually the mouth and genitals,
and it is largely developed by oral or vaginal sex. Type 1 herpes is more common than
type 2 herpes, although the incidence of type 2 has been increasing gradually.
- The latent period usually lasts from a few days to several weeks, although symptoms are
sometimes observed after several months or even a few years.
- Herpes is transmitted from mother to fetus: if herpes is found near to birth, the probability
of infection is about 40-50%, and, if the infant is infected, the mortality rate is 60%. Even
if
the infant survives, there is a risk that half of its brain will be damaged and fatally
influenced.
- Pathogen: herpes simplex virus
The herpes virus is from 100 to 200nm in size and contains relatively large DNA, and is
divided into type 1 and type 2. The type 1 virus usually causes herpes (blisters) around
the lips, while the type 2 virus usually causes herpes in the genital area. Nevertheless, the
type 1 infection can be observed in the genital area.
4) Gonorrhea (Gonococca Urethritis Gonorrhea)
- Gonococcal urethritis is a very old STD which results in urethral infection by a bacterium
that is transmitted by sexual contact. Infection can also occur through oral or anal contact.
The latent period is 2-3 days, and is characterized by the fast development of symptoms.
Gonococcal urethritis develops several days after sexual contact. In general, urethral
itching, frequent urination, and stinging dysuria are commonly observed, and a yellow
urethral discharge is sometimes observed after a few days.
- Female patients are sometimes asymptomatic, but complications such as pelvic
inflammation are easily observed, causing lower abdominal pain, as a result of this
disease. Complications of gonococcal urethritis include oophoritis, salpingitis,
endometritis and infertility, and sometimes cystitis.
- Pathogen: Neisseria gonorrhoeae
These Gram-negative bacteria responsible for causing gonorrhea, characterized by a
pair
of kidney-shaped diplococcus, are commonly found in the pus which accompanies
urethritis.
Just 0.6 ∼ 1 in size and usually surrounded by white blood cells, its size is
almost regular. (Several sizes have been observed in cultured bacteria). Infection
develops in the healthy mucous membrane after contact with infected genitals (sexual
intercourse · kiss · birth canal penetration), and causes endocarditis, urethritis,
inflammation of the genital mucous membranes, arthritis, and bacteremia.
5) Non-gonococcal urethritis
- Nongonococcal urethritis is urethritis altogether caused by pathogens except the one
causing gonorrhea. It is urethritis infected and developed by pathogens except the one
causing gonorrhea through sexual intercourse or sexual activity. Its symptoms are not as
severe as those of gonococcal urethritis, but it is a relatively incurable disease.
- It is largely seen in males but, in female patients, complications such as acute cystitis
are observed. With regard to age, it is usually observed in sexually active age groups, as
in the case of gonococcal urethritis.
- The development of the symptoms is slow compared to those of gonococcal urethritis,
and its progression is also slow. White mucous discharge is characteristic in this disease.
Symptoms that stimulate the urethra such as frequent urination, nocturia, hematuria, and
urgent urination can appear. Sometimes dysuria or urethral pruritis might appear; very
occasionally, no symptoms are observed. If prostatitis accompanies the infection, then
perineal discomfort, scrotal pain, and lower abdominal pain are observed and,
occasionally, epididymitis.
- Pathogen: Trichomonas vaginalis
A protozoa causing nongonococcal urethritis, it is 10-7um in size, pear-shaped , and
motile with 4 flagella.
It inhabits the female genitalia and male urethra and prostate, and
is transmitted by direct contact in a wet environment.
- Pathogen: Mycoplasma hominis
It mainly exists in the urogenital organs, and is related to nongonococcal urethritis,
prostatic urethritis, metria, endometritis and cervicitis. As regards its general
characteristics, it shows pleomorphism due to the absence of cell walls, and is about
0.2-0.3 ㎛ in size, small enough to pass through a 450 ㎚ filter. It is not usually stained in
general stains for bacteria, but rather in Giemsa's stain.
- Pathogen: Mycoplasma genitalium
This pathogen causes nongonococcal urethritis, is about 0.3-0.5um in size, and has the
smallest, simplest structure.
- Pathogen: Ureaplasma urealyticum
The pathogen causes nongonococcal urethritis and is found in 60-80% of adults. It also
has the characteristic of being transmitted to newborns, in whom meningitis and
pneumonia can develop, so further infant mortality might be observed.
- Pathogen: Chlamydia trachomatis
Consisting of 30-60% of nongonococcal urethritis, it is also detected in 4-45% of male
gonococcal urethritis along with the pathogens that cause gonorrhea or after the
disappearance of pathogens causing gonorrhea.
It shows the highest incidence among
cases of post-gonococcal urethritis, and is asymptomatic as an STD but closely related
to infertility. Currently, this pathogen is the most common cause of STDs, with 80% of
cases showing no symptoms, while other symptoms such as mucopurulent vaginal
discharge, dysuria and frequent urination can be observed.
- Pathogen: Candida albicans
This fungus, responsible for causing nongonococcal urethritis or vaginitis, is a round or
oval-shaped single colorless cell. When it is of the yeast phenotype, it is proliferated by
budding and the size of the blast cell is about 4-6μm. Apart from blast cells, hyphae and
pseudohyphae by budding are formed. This pathogenic fungus causes candidiasis, which
is characterized by fermentation in addition to oxidative degradation. It exists in the mouth
or skin of human beings and animals, and is harmless to the human body in its normal
state but proliferates abnormally inside the body to develop cadidiasis in cases of long-
term administration of antibiotics or decreased immunity of the human body. Infection
frequently occurs through the mouth and genital regions.
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