- 1 Sexually Transmitted Infections or Diseases (STIs or STDs) – Risk Factors, Diagnosis, and Prevention
- 1.1 Some Important STDs
- 1.2 1. Syphilis
- 1.3 2. Gonorrhoea
- 1.4 3. AIDS (Acquired Immuno Deficiency Syndrome)
- 1.5 4. Hepatitis B
- 1.6 5. Genital Herpes
- 1.7 6. Genital Warts
- 1.8 7. Chlamydiasis
- 1.9 8. Trichomoniasis
- 1.10 9. STD Caused by Nematode
- 1.11 10. STD Caused by Parasite
- 1.12 11. STD Caused by Fungus
- 1.13 12. Chancroid
One of the most fascinating Biology Topics is the study of genetics and how traits are passed down through generations.
Sexually Transmitted Infections or Diseases (STIs or STDs) – Risk Factors, Diagnosis, and Prevention
The diseases which are transmitted through sexual intercourse from an infected person to a healthy person are collectively called sexually transmitted diseases (STD) or venereal diseases (VD).
Causative Agents or Pathogen
STDs are usually caused by Viruses, Bacteria, Protozoa, Nematodes, Fungi, etc.
Some Pathogens and Sexually Transmitted Diseases
- Virus Transmitted Diseases: AIDS, Hepatitis-B
- Bacteria Transmitted Diseases: Gonorrhoea, Syphilis
- Protozoa Transmitted Disease: Trichomoniasis
- Chlamydia Transmitted Disease: Chlamydiasis
Mode of Transmission
STDs are transmitted by
- Unprotected sexual intercourse with infected persons
- Sharing of needles, razors, surgical instruments
- Transfusion of blood from an infected mother to foetus and from an infected person to a healthy person.
Prevention of STDs
For the prevention of STD, the following principle should be taken:
- Avoid sex with an unknown person.
- Avoid sex with multiple partners.
- The condom should be used during intercourse.
- Don’t share needles, razors, etc.
- Always use a disposable syringe.
- Avoid blood transfusion from an infected person.
Some Sexually Transmitted Diseases:
|1. Gonorrhoea||Neisseria Gonorrhoeae|
|2. Syphilis||Treponema Pallidum|
|3. AIDS||HIV (Human Immuno Deficiency Virus)|
|4. Hepatitis B||HBV (Hepatitis B Virus)|
|5. Genital Herpes||Genital Simplex Virus|
|6. Genital Warts||Human Papilloma Virus (HPV)|
|7. Trichomoniasis||Trichomonas Vaginalis|
|8. Chlamydia||Chlamydia Trachomatis|
Some Important STDs
Pathogen or causative agent: This disease is caused by the bacteria Treponema pallidum.
Incubation period: 10 – 90 days.
Mode of Transmission: The disease is transmitted through sexual intercourse, blood, and other intimate body contacts like kissing, etc. Syphilis is found to occur amongst persons in large cities, towns, and industrial belts.
Symptoms: At the early stage of syphilis ulcers are found on the genitalia. After that ulcer is healed and skin lesions, rashes, and swollen joints are found. If proper treatment is not provided to the patients they may suffer from cardiac, neurological, ophthalmic, and auditory problems.
Classification of Syphilis:
I. Acquired Syphilis
Early Syphilis: The latent period is 14-28 days, it may remain 90 days. It is of three types:
- Primary Syphilis: In this syphilis, the ulcer is formed in the infected parts mainly in the sex organs. In 10% of patients fingers, lips, tongues, tonsils, and rectum is also infected. Due to this infection nonspecific and specific antibodies are formed.
- Secondary Syphilis: This syphilis starts within 6-8 weeks after the formation of an ulcer in primary syphilis. The symptoms of this syphilis are Mild fever, Uneasiness, Headache, Pain in muscles and joints, and Rashes on the neck, hands, legs, palms, and soles in 70% of cases.
- Latent Syphilis: This syphilis is transmitted by sexual means, within 2 years of infection of early syphilis. This is also transmitted from the mother to the embryo for some years.
Delayed Syphilis: This syphilis remains active for some years or whole life.
- Tertiary Syphilis: This type is seen after two years. This syphilis infects the skin, mucus membrane, and bone.
- Quaternary Syphilis: Cardiovascular and nervous system is infected by this disease. The affected person may die after some days.
II. Congenital Syphilis
It is syphilis in which some events are seen after 4 months of pregnancy. The events are Abortion or delivery of an immature child, Delivery of syphilis infected child, Symptoms of syphilis appearing in the baby after a few weeks of birth, and A child born with latent syphilis may remain healthy or develop symptoms in the last life. In addition, two more types of syphilis are identified. They are as follows:
- Cardiovascular Syphilis: This syphilis is seen after many years of infection of primary syphilis. In this syphilis, mainly the aorta and aortic valves are attacked.
- Neurosyphilis: This syphilis is formed after many years of infection and abnormalities are seen in cerebrospinal fluid (CSF).
Diagnosis of Syphilis
- VDRL (Venereal Disease Research Laboratory) Test: By this test, non-specific antibodies without Treponema are identified. In addition, RPR (Rapid Plasma Reagin) test also identifies non-specific antibodies.
- TPHA (Treponema Pallidum Haemagglutination Assay) Test: This test helps to identify specific antibodies. In addition by EIA (Treponemal antigen-based Enzyme Immuno Assay), Immunoglobulin G (IgG) and Immunoglobulin M (IgM) are identified.
When the VDRL test and TPHA test give different results, then FTA-ABS (Fluorescent Treponemal Antibody- Absorption) test is done for confirmation.
Remedies/Prevention of Syphilis:
- Care should be taken during sexual connection.
- It is better not to do sexual connections with individuals attacked with Syphilis.
Medicines for Treatment:
- Procaine benzylpenicillin – 1.2 million IU daily for the first 10 days.
- Benzathine penicillin G – 2.4 million U IM once a week for two doses.
- Doxycycline hydrate – 100 mg orally twice for 14 days.
- Erythromycin – 500 mg orally every 6 hours for 14 days.
Delayed Latent Syphilis:
- Procaine benzylpenicillin – 1.2 million IU IM once daily for 20 days.
- Benzathine penicillin G – 2.4 million U IM weekly for 3 days.
- Doxycycline hydrate – 100 mg orally every 12 hours for 30 days.
- Tetracycline – 500 mg orally, 4 times daily for 30 days.
Erythromycin – 500 mg orally every 6 hours for 14 days.
- Benzylpenicillin – 50,000 U/kg in TV every 12 hours for the first 7 days.
- Procaine Penicillin – 50,000 U/kg IM daily for 10 days. [U = unit; TV = intravenous; IM = intramuscular]
Pathogen or causative agent: it is a sexually transmitted disease, caused by gram-negative cocci bacteria, Neisseria gonorrhoeae.
Incubation period: 2 – 5 days.
Site of Infection:
- Lower genital tract
- Urinary tract
- Epididymis and Prostate gland
Mode of Transmission:
- Sexual contact
- Oral sex
- Finger, contact in eyes
Symptoms of Gonorrhoea:
- Burning sensation and itching in the urethra after some days of sexual connection.
- Secretion of pus from urethra.
- Irritation in epididymis.
- Discomfort and bleeding from the rectum.
- Fever, headache, and illness.
- Secretion of blood with pus from the vagina.
- Bleeding in the middle of the menstrual cycle.
- Irritation in the cervix.
Diagnosis of Gonorrhoea:
Gonorrhoea is not diagnosed easily like Syphilis, especially in females. No good serological or skin test is known till now.
Present Practice Tests:
- Smear Examination: The presence of gonococci in the smear of the urethra and cervix is the genuine test.
- Oxidase Test and Sugar Reaction: By artificial growth of the germ in the laboratory, the presence of Gonorrhoea disease is confirmed by this test.
- Fluorescent Antibody Test: Gonorrhoea is quickly diagnosed by this test.
Remedies/Prevention of Gonorrhoea:
Gonorrhoea disease can be cured in the preliminary stage by antibiotics like penicillin, streptomycin, and ampicillin. But nothing can be done in chronic conditions and the patients die in most cases. Avoid polygamy and restricted one partner.
3. AIDS (Acquired Immuno Deficiency Syndrome)
Pathogen or causative agent: It is a life-threatening disease due to HIV (Human Immuno Deficiency Virus). HIV was discovered by Luc Montasnier of France in 1983 and Robert Gallow of America in 1984. It is an RNA virus of the sub-group Lentivirus of Group Retrovirus. HIV contains reverse transcriptase enzyme which forms DNA from RNA. AIDS was first identified in America and since then it is recognized as the second life-threatening disease in the world.
According to statistics from World Health Organisation (WHO) in 2000, about 36 million human beings are attacked by AIDS in the whole world. AIDS is more in African countries. In West Bengal AIDS was identified in 1986. Statistics show that young boys and girls are attacked more by AIDS nearly in equal proportion. Homosexual males and commercial sex workers are also attacked more.
Incubation period: 6 months to 10 years.
Mode of Transmission/Infection of HIV:
- Through sexual contact;
- Transfusion of HIV-contaminated blood;
- Use of the same injection syringe for different persons without sterilization;
- From the suffering mother (carrier) to the embryo through the placenta;
- Artificial insemination in the uterus;
- From suffering mother’s milk to the baby;
- Use of the same blade or razor in the saloon for different persons;
- Transplantation of the tissue from one person to another.
Symptoms of AIDS:
The symptoms are expressed in three stages:
(a) Primary or Acute Stage: It starts after 3-4 weeks of infection and lasts for 2 weeks. The symptoms are as follows:
- Fever, fatigue, ulcer in the throat, and commonly lymph adenopathy.
- Rash at trunk, palm, and sole.
- Low WBC count in the blood.
- The appearance of HIV antibody after 3-4 weeks of infection.
(b) Middle, Latent Stage: It may last for a long time. The symptoms are as follows:
- The patients are asymptomatic with the absence or presence of less virus in the blood.
- HIV is formed in the lymph node.
- AIDS-related complex (ARC) is seen.
- Continuous fever with fatigue.
- Loss of body weight with lymph adenopathy.
(c) Late Immuno Deficiency Stage: The symptoms are as follows
- Reduction of CD4 cells (400 per mm)
- Pneumocytosis carinii pneumonia disease
- Kaposi’s sarcoma
- Isolated cerebral lymphoma
- Candidiasis (injury at mouth, pharynx, and oesophagus).
Diagnosis of AIDS:
The presence of HIV antibodies in the blood is identified by the screening test. This is done by-
- ELISA (Enzyme-Linked Immuno Sorbent Assay): To detect the presence of HIV antibodies in the blood serum.
- Western Blot Test: To detect HIV protein in the blood.
Prevention of AIDS:
The following measures should be taken to prevent AIDS:
- Prevention of Transmission Through Sexual Connection:
- The males should use condoms during sexual intercourse
- It is better to avoid sexual contact with commercial sex workers.
- Prevention of Blood-Borne Transmission:
- The presence of HIV antibodies in the blood of Blood Bank should be tested before use.
- Transfusion of HIV-positive blood must be avoided.
- The same syringe should not be used .to collect blood from more than one person.
- Precautions of Health Workers and Surgeons:
- The health workers should use gloves in hand to work with blood, other body fluid, semen, etc. in the laboratory.
- Surgeons should always use gloves on their hands. The knife, scissors, blade, etc. all instruments must be sterilized before operation.
- Public Education:
- The public should be made aware of the mode of transmission of AIDS and its bad effects.
- The public should uplift their living standards to avoid AIDS.
- No vaccine has yet been discovered to prevent AIDS.
- The first medicine to control AIDS is Zidovudine (ZDV AZT). This medicine has been effective to neutralize the symptoms of AIDS and to reduce the rate of death.
- The medicines in the following stages are Lamivudine (3TC), Didanosine (dd), Zalcitabine (DDC), Stavudine (d4T), and Abacavir. Each of these medicines completes with a natural nucleoside.
4. Hepatitis B
Pathogen or causative agent: Hepatitis B is the inflammatory disease of the liver due to virulent infection of the Hepatitis B virus (HBV). Scientist Bloomberg discovered this DNA virus in 1963. Hepatitis B is a significant health problem throughout the world. Statistics show that in 1984 about 1783 persons were attacked by HBV in epidemic form in Ahmedabad city of India.
Incubation Period: 30 – 80 days.
Structure of HBV: HBV is a complex DNA virus with a diameter of 42 nm, which is made of a capsule and a core within it. The core contains ds DNA and DNA polymerase enzyme. The virus is called the Dane particle and its capsular matrix called Hepatitis B Surface Antigen (HBsAg) flows in the blood.
HBV Antigen: HBV has three prominent antigens-
- Australian antigen or Hepatitis B surface antigen (HBsAg)
- Hepatitis B core antigen (HBcAg)
- Hepatitis e antigen (HBeAg).
HBV antibody: Three types of antibodies are produced by HBV infection in man-
- Surface antibody (anti-HBs)
- Core antibody (HBc)
- E antibody (HBe).
Mode of Transmission of HBV:
- Transfusion of infected blood.
- Use of infected and unsterilized syringes, needles, and surgical instruments.
- Use of others’ razors, towels, etc in the family.
- From the infected mother’s blood to the embryo through the placenta.
- Through vaginal fluid during sexual intercourse.
- Kissing and other sorts of contact with the infected body.
Symptoms of Hepatitis B:
- Cirrhosis of the liver (15-20% cases)
- Hepatocellular carcinoma
- Chronic hepatitis
- Liver failure
- About 80% of liver cancer is due to Hepatitis B.
Diagnosis of Hepatitis B:
The presence of HBV antigens and their corresponding antibodies ensures the infection of the disease. The presence of Hepatitis B Surface Antigen (HBsAg) and its antibody (anti HBs) indicates virulent infection. The presence of core antibody (HBc) is an effective diagnosis in the epidemic.
Remedies/Prevention of Hepatitis B:
The prevention of Hepatitis B has been effective in 95% of cases after the discovery of an active vaccine (HB vax) and particular immunoglobulin (Ig).
1. HB Vax: It stimulates the formation of a surface antibody (anti-HBs). The vaccination is completed in three doses. After 3-5 years a booster dose of the vaccine is given. In children below 10 years of age, half of the above quantity of vaccine is given as per time table.
Hepatitis B Vaccination Time Table:
|1st dose||1 ml||Determined date|
|2nd dose||1 ml||After one month of 1st dose|
|3rd dose||1 ml||After six months of 1st dose|
2. Hepatitis B Immunoglobulin (HBIG): This is applied to develop immunity in persons having Hepatitis B surface antigen (HBsAg) as in surgeons, nurses, laboratory workers, newborn babies of carrier mothers, etc. The recommended dose of HBIG is 0.05-0.07 ml. per kg of body weight. The dose is applied at 30 days interval. It remains active for 3 months.
3. Passive-Active Immunization: It is more effective to apply HBIG and HB vax at a time. In this case, one dose of HBIG (0.05-0.07 ml per kg of body weight) is applied within 24 hours of infection and another dose of HB vax. is given within 7 days of infection. The 2nd and 3rd doses are given after 1 month and 6 months respectively of the 1st dose.
Medicinal Treatment of Hepatitis B:
- Lamivudin: It is an anti HBV nucleoside medicine. It prevents the action of the HBV-DNA polymerase enzyme. This medicine is successful in 93-100% of cases.
Dose: 100 mg per day for 1 year.
- Interferon: This medicine is effective for those who are HIV-negative, Not infected at the time of birth, and Whose transaminase concentration in serum is more.
Other Preventive Measures of Hepatitis B
- Test of HBV infection of donor’s blood before transfusion.
- To discard blood having Australian antigens.
- Proper sterilization of all instruments used by the health workers.
- Health education especially amongst illiterate persons.
5. Genital Herpes
Pathogen: Herpes simplex virus
Mode of transmission: From sexual contact and genital secretion, saliva may transmit the virus from the mouth or lip.
Symptoms of Genital Herpes:
- Vesiculopustular lesions are followed by clusters of painful erythematous ulcers over external genitalia and also in perianal regions.
- There is a fever, headache, pain, and itching.
- In women, herpes sores could be hidden inside the vagina.
- There are also vaginal or urethral discharges with swelling of lymph nodes.
- Urethral and cervix infections also occur.
Diagnosis of Genital Herpes: Antigen detection, PCR, and nucleic acid hybridization. The virus remains in the body forever and lesions come back from time to time through herpes sore disappear within 2-3 days.
Treatment of Genital Herpes: Medicine treatment with acyclovir, valacyclovir, or famciclovir.
6. Genital Warts
Pathogen: Human Papilloma Virus (HPV).
Mode of transmission: From sexual intercourse, skin-to-skin contact.
Symptoms of Genital Warts:
Warts (earlier hard outgrowths with a whitish horny surface but later fleshy and cauliflower-like appearance) develop over the skin and mucosal surface of the external genitalia and perianal area. In women, infection may spread to the vagina and cervix.
Diagnosis of Genital Warts: Antibody detection, culture, and DNA hybridization.
Treatment of Genital Warts:
- Cryosurgery is used in the removal of warts. Warts also can be removed using creams.
- Podophyllum preparations (The dry rhizome and roots of Podophyllum pellotum) are also useful.
Pathogen: Chlamydia trachomatis.
Incubation period: 1 weak through the vaginal fluid.
Mode of transmission: It spreads from sexual contact.
Symptoms of Chlamydiasis:
- This pathogen causes trachoma and perinatal infection.
- Urethritis, epididymitis, unilateral scrotal pain, tenderness, and swelling.
- Mucopurulent discharge, cervicitis, inflammation of fallopian tubes (if untreated can cause a woman to become infertile or to have ectopic pregnancy).
- Prostitis – rectal pain with mucous and occasional bleeding.
Diagnosis of Chlamydiasis: Gram staining of discharge, antigen detection, nucleic acid hybridization.
Treatment of Chlamydiasis: Antibiotic treatment with tetracycline, erythromycin, azithromycine, etc.
Pathogen: Trichomonas vaginalis (Protozoa)
Mode of transmission: Through sexual intercourse.
Symptoms of Chlamydiasis:
- Vaginitis with foul-smelling, yellow vaginal discharge and burning sensation.
- In males – urethritis, epididymitis, prostitis etc.
Diagnosis of Trichomoniasis: Microscopic examination, culture, and immunofluorescent antibody staining.
Treatment of Trichomoniasis: Metronidazole application is the best treatment, but the partner should be treated simultaneously.
9. STD Caused by Nematode
Pathogen: Enterobius vermicularis (Pinworm)
Mode of transmission: When the patient scratches the affected part, the eggs of nematode easily get under the nails and transmit through the mouth. There is also the possibility of transmission through sexual intercourse.
Symptoms: Itching of the anus, Inflammation of mucous membrane of colon and appendix, Abdominal pain, nausea, diarrhoea, etc.
Treatment: Antihelminthic drugs are recommended.
10. STD Caused by Parasite
Pathogen: Pubic lice or crabs
Mode of transmission: It infects and attached to the base of pubic hair. They live by sucking blood. They spread through sexual contact or passed from clothing.
Symptoms: Itching is the lice suck blood and irritation occurs.
Treatment: A prescription medication, counter shampoo.
11. STD Caused by Fungus
Pathogen: Candida albicans (Vaginal yeast)
Mode of transmission: Through sexual contact.
Symptoms of STD Caused by Fungus:
- Painful inflammation of the vagina.
- Thick, cheesy discharge often.
- Painful inflammation of the urethra of males.
Treatment of STD Caused by Fungus: Uses of antibiotics like clotrimazole, miconazole, etc.
Pathogen: Haemophilus ducreyi (Bacteria)
Mode of transmission: Genital contact.
Symptoms of Chancroid: Ulcers can appear over the external genitalia, and lymph nodes can be swollen.
Diagnosis of Chancroid: Clinical symptom.
Treatment of Chancroid: Antibiotics like erythromycin, ciprofloxacin, ceftriaxone, etc.