Sexually transmitted diseases (STDs) or infections also known as “Venereal diseases” are primarily transmitted through vaginal, oral or anal sex involving blood, semen or vaginal fluids. It can be caused by bacteria, viruses or parasites. Following are the common STDs:
- AIDS (Acquired Immunodeficiency Syndrome)
- Chlamydia
- Gonorrhea
- Syphilis
- Human Papillomavirus (HPV)
- Herpes Simplex Virus (HSV)
Introduction
STDs can affect individuals of all ages, genders, and sexual orientations. Many STDs can be asymptomatic, meaning infected individuals may not show any symptoms. For example, about 70-90% of women and 50% of men with chlamydia (bacterial infection) show no symptoms, making regular screening crucial.
Sexually Transmitted Diseases
It
is caused by a Virus called Human Immunodeficiency Virus (HIV) belonging to the
family Retroviridae (RNA as genetic material) and the genus Lentivirus. Viruses
of this genus causes serious, persistent and long-term infections.
HIV
attacks the major parts of our body’s defence (immune) system such as Helper T
cells (CD4+), macrophages, and dendritic cells. This gradually causes failure
of immune system and increases susceptibility to many opportunistic
infections which causes AIDS.
Transmission:
- Sexual contact (vaginal, anal, or oral sex).
- Blood-to-blood contact (e.g., sharing needles, blood transfusions).
- Mother-to-child transmission (during childbirth or breastfeeding).
Symptoms:
- Acute
(intense) HIV infection: fever, sore throat, fatigue, muscle aches,
swollen lymph nodes, nervous system related problems (confusion, anxiety etc.),
rapid weight loss, mouth and genital ulcers.
- AIDS: HIV infection ultimately leads to Severe immune system damage which results to opportunistic infections and certain cancers (skin, lungs, liver and lymphatic system). Both infections and cancer can be prevented by a healthy immune system but AIDS progressively weakens the immune system.
Diagnosis:
- ELISA
test: is used to detect either antibodies produced in
the blood of infected person against HIV infection or antigen (p24
protein) of virus. If ELISA is positive than it is confirmed by another test
called western blot test.
- Nucleic
acid amplification test (NAAT): used to detect the RNA of
the virus in blood sample of the patient using PCR amplification
technique. The positive test indicates presence of virus in the blood of
infected person. This test detect HIV infection sooner than any other
test.
Treatment:
Antiretroviral therapy (ART) is an
antiviral therapy containing combination of drugs (Abacavir, lamivudine, and zidovudine) to control the spread of virus and
prevent progression to AIDS.
Prevention:
- Safe sex practices (condoms).
- Pre-exposure prophylaxis (PrEP): Certain people do not have HIV infection but are at higher risk of getting this infection e.g. sex workers and drug addicts (using syringes). Such people can use certain medicines for Prevention the HIV infection e.g. PrEP oral medicine (emtricitabine / tenofovir DF) daily.
(Note: This medicine may cause lactic acidosis in
blood and kidney failure). Alternatively, injectable medicine (Cabotegravir)
can be used once in a month (Note: It can cause liver problems, allergic
reactions and mood swings).
- Regular testing and early treatment.
2. Chlamydia
Cause: Chlamydia trachomatis bacterium.
It is a Gram-negative bacterium.
It exists in two forms: The Infectious Elementary Body (EB) and the Replicative
Reticulate Body (RB). EBs attach to and enter human epithelial cells,
transforming into RBs within a vacuole which replicate by binary fission. Chronic
infection can lead to tissue damage and inflammation in urinary tract, uterus
and testis.
Transmission:
- Unprotected vaginal, anal, or oral sex.
- Vertical transmission from mother to newborn during childbirth.
Symptoms:
- Often asymptomatic (no symptoms).
- Symptoms may appear in: Women: abnormal vaginal discharge, burning sensation during urination, pelvic pain. Can cause cervicitis (Inflammation of the uterus opening), urethritis (inflammation of Duct through which urine comes out), and pelvic inflammatory disease (PID) especially the Fallopian tubes (carrying eggs to uterus) in women. Men: discharge from the penis, burning sensation during urination, testicular pain. Epididymitis (inflammation of small tubes in Testis carrying sperms) in men.
- Potential for infertility in both male and females.
Diagnosis:
Nucleic acid amplification tests (NAATs) on urine samples or swabs. It is used
to detect the DNA of the bacteria in blood sample of the patient using PCR
amplification technique.
Treatment:
Antibiotics (azithromycin or doxycycline).Prevention:
Safe sex practices.
Regular screening for sexually active individuals.
3. Gonorrhea
Cause: Neisseria gonorrhoeae bacterium.
It is a Gram-negative diplococcus bacterium with outer membrane pili and
proteins Opa that
helps in attachment and colonization to host cells. Human cells have lysozyme
to breakdown the bacterial cell but this bacterium produces lysozyme
inhibitors to save the bacteria. Induces inflammation and purulent
discharge.
Transmission:
Sexual contact (vaginal, anal, or oral sex).
Vertical transmission from mother to newborn during childbirth.
Complications:
- Can cause urethritis (Inflammation of the urethra and painful urination), cervicitis (Inflammation of the uterine cervix), and pelvic inflammatory disease (PID).
- Dispersed gonococcal infection can affect joints and skin.
- Potential for scrotal swelling and infertility.
Transmission:
Unprotected vaginal,
anal, or oral sex.
Symptoms:
Often asymptomatic.
Women: increased vaginal discharge, pelvic pain, burning sensation
during urination.
Men: pus-like discharge from the penis, burning sensation during
urination, testicular pain.
Anal infection may cause discharge,
bleeding and painful bowel movement
Diagnosis:
- Gram staining for detection of bacterial cells in vaginal, cervical, urethral, anal discharge or swabs and urine samples
- Antimicrobial sensitivity test to select the right and effective medicine or treatment.
Antibiotics (ceftriaxone and azithromycin).
Prevention:
Safe sex practices.
Regular screening.
Cause: Treponema pallidum bacterium.
Treponema pallidum is a Gram-negative spirochete (a long spiral
bacteria) characterized by its helical shape and motility. The bacterium
penetrates mucous membranes or breaks in the skin. Spreads via the lymphatic
system and bloodstream.
Causes primary, secondary, and tertiary stages of syphilis, with potential
involvement of multiple organ systems.
Transmission:
- Direct contact with syphilitic sores during sexual activity.
- Vertical transmission from mother to fetus during pregnancy.
Complications:
- Primary syphilis: painless chancres (small hard painless nodule).
- Secondary syphilis: systemic symptoms and reddish-brown skin rashes on chest, back and pelvis without itching
- Tertiary syphilis: severe damage to cardiovascular and nervous systems, liver and bones. Person may become deaf and paralyzed.
Diagnosis:
Blood tests:
- Treponemal tests includes detection of antibodies in blood of the patient. These antibodies are produced against the proteins of the bacteria hence is specific for Treponema pallidum.
- Non-treponemal test: It is not specific for the Treponema pallidum also called Venereal disease research laboratory test (VDRL)
- Detection of bacteria by darkfield microscopy in fluids of infected tissues or lymph nodes.
Treatment:
Antibiotics (penicillin).Prevention:
Safe sex practices.Regular screening.
5. Human Papillomavirus (HPV)
Cause: Human papillomavirus.
HPV is a non-enveloped, double-stranded DNA virus. Belongs to the
Papillomaviridae family. High-risk viruses are HPV-16 and HPV-18
types.
HPV infects basal epithelial cells
through micro-abrasions occur during sex. The virus can remain latent (inactive)
or cause cellular changes leading to warts (firm elevated skin growths) or
malignancies.
DNA of High-risk HPV types integrate into the host genome, leading to dysplasia
(Abnormal development of organs or cells) and potential cancer development
(cervical, anal, penile, and oropharyngeal cancers).
Transmission:
- Skin-to-skin contact during sexual activity.
- Non-sexual routes (e.g., fomites such as infected inanimate objects) are rare but possible.
Symptoms:
- Often asymptomatic (No symptoms).
- Genital warts (pink, skin-coloured, purple or brown)
- Certain strains (high risk HPV) can lead to cancers (cervical, anal, throat). The immune system if unable to control the infection than in 2-3% of cases after 10-20 years of infection it may lead to cancer.
Diagnosis:
- Pap tests (Papanicolaou test) involves taking samples from the vagina or cervix. The smear of the sample stained with hematoxylin as nuclear stain, with 2 counterstains (orange G and Eosin Azure) to nuclear details—membrane irregularities, chromatin pattern, for detection of cancer cells.
- HPV DNA test: For detection of DNA of the virus using PCR amplification. If DNA of virus is present in the cervical sample it means Human papillomavirus is present and is responsible for causing infection.
PAP smear for cancer detection
Treatment:
- No cure for the virus itself.
- Treatment for warts includes: Cryotherapy: using liquid nitrogen to freeze and remove warts. Electrocautery:
using electrical current to burn and remove warts. Laser therapy: using
a high-powered beam to take out the tissue. Surgical removal: to
cut away warts using local anaesthesia.
Prevention:
- HPV vaccination: 9-valent HPV vaccine, quadrivalent HPV vaccine, and bivalent HPV vaccine to protect against cancer causing HPV-16 and 18.
- Safe sex practices.
- Regular screening.
6. Herpes Simplex Virus (HSV)
Cause: Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2).
HSV is an enveloped, double-stranded DNA virus Belongs to the Herpesviridae
family.
HSV-1 primarily causes oral herpes; HSV-2 primarily causes genital herpes.
The virus enters through mucous membranes
or skin breaks causes Painful blisters or sores. Neonatal (infants) may
get herpes if transmitted during childbirth.
Transmission:
- Skin-to-skin contact during sexual activity.
- HSV-1: oral contact.
- HSV-2: genital contact.
- Mother to child during childbirth
Symptoms:
HSV-1 can lead to painful cold sores or fever blisters around the mouth. In rare cases, HSV-1 can cause herpetic whitlow (infection of the fingers) or herpes keratitis (infection of the eye), which can result in vision loss.
Diagnosis:
Visual Inspection:
By examining visible sores or blisters in the affected area (mouth, genital, or anal regions). Recurrent Symptoms are suggestive of herpes.
Viral Culture: A sample from a fresh sore or blister is collected using a swab and sent to the lab where the virus is cultured. It is Highly specific but it may not detect the virus in older lesions.
- Viral antigen or antibody detection test in blood or blisters using ELISA. Blood tests that detect antibodies to HSV-1 and HSV-2. It cannot differentiate between current or past infection, antibodies may take weeks to develop after initial infection.
- Detection of Virus DNA in sores or blisters using
Polymerase chain reaction (PCR) tests conforming presence of virus. It can differentiate between HSV-1 and HSV-2 but test is more
expensive than other methods.
Treatment:
Prevention:
Safe sex practices.
Antiviral therapy to reduce transmission
risk.
Conclusion
Sexually transmitted diseases are a significant public health challenge. Understanding their causes, symptoms, diagnosis, treatment, and prevention is essential for reducing their prevalence and impact. Safe sex practices, regular screening, and vaccination are critical components of effective STD prevention and control.Viruses
like HIV can rapidly mutate, hence can escape from the attack of immune system,
also developing resistance to antiretroviral drugs. This evolutionary
adaptability makes controlling and treating these infections a significant
scientific challenge.
A
striking problem in managing many STDs is their ability to remain asymptomatic
in a large number of infected individuals. This silent transmission emphasizes
the importance of regular screening to identify and treat infections early.
The
development of the HPV vaccine stands as a milestone in public health. It
significantly reduces the incidence of HPV-related cancers and genital warts that
save lives and reduces disease burden.
Public
health awareness, sex education and knowledge about controlling antibiotic
resistance strategies underlines the importance of education, awareness, in
controlling the spread of STDs.
.png)
.png)
.png)
0 Comments