STDs
Definition of STDs:
Sexually transmitted diseases (STDs) are communicable diseases that are
transmitted by sexual contacts. The term STDs describes a mode of
transmission rather than the site of infection( as in venereal diseases) .Many of
them are not restricted to genital tract , but of systemic nature. Consequently ,
the term STDs has gradually replaced the term venereal diseases.
Over 20 STDs are now known.
Classfications of STDs :
A) Bacterial:
Treponema palidum
Neisseria gonorrhea
Chlamydia
B) Viral:
•Human immunodeficiency virus (HIV)
•Herpes simplex virus (HSV)
•Human papilloma virus HPV)
•Hepatitis B virus
•Hepatitis C virus
C) Fungal: As candida
D) Protozoal: Trichomonas vaginalis
The incidence of STDs cannot be accurately determined
because:
- Defects in the notification system.
- Where notification exists, reporting systems are deficient & inaccurate.
- Asymptomatic infections are very common.
- Social stigma conceals cases so many patients seek alternative sources of
medical care, including self-medication.
- Diagnostic facilities in health services are often either very limited (microscope
only) or absent .
- Risk groups are difficult to identify.
- Some heath care workers are not aware about the standard case definition of
HIV.
Complications of STDs
1-Women during the reproductive period: pelvic inflammatory diseases,
infertility and urethral stricture
2. During pregnancy: ectopic pregnancy , abortion & difficult labour .
3. For infants: stillbirth & neonatal deaths, congenital syphilis, blindness,
Prematurity, Hepatitis B infection
4. Late complications of syphilis in different systems of the body.
5. Cancers related to STDs:
• Cancer cervix:
- Human papilloma virus HPV)
- Herpes simplex virus (HSV)
• Hepatocellular carcinoma :
- HBV
• Kaposi's sarcoma, lymphoma of the CNS
- HIV
A)Primary preventive measures for STDs:
I) General Measures:
• Emphasis on religion ,moral and values that prohibit extramarital sex
• Health education: The aim is to help individuals to
• alter their behaviors to avoid STDs ,
• minimize disease transmission.
• avoid extramarital sexual relations.
• Social welfare measures: include; provision of recreation facilities in the
community
II) Specific measures:
1) Vaccination: The only available vaccine now is HB vaccine.
2) Prophylactic antibiotics before or after exposure are not recommended
because of the following:
No single antibiotic covers all STDs
Emerging resistant strains
Allergic reactions
Creating sense of security among persons receiving them, that
they practice sex without limitations.
3)Prevention of Parenteral transmission of STDs:
1-Avoid blood transfusion if not seriously needed
2-Screening of blood before transfusion for syphilis, HBV, HCV and HIV. If blood
cannot be screened, exclude high- risk donors through the following:
a-Refrain donors practicing risky behaviors (Addiction)
b-Obtaining history about suggestive symptoms.
c. Physical examination of the donor can identify suggestive signs as
jaundice, unusual mucosal or skin lesions, lymphadenopathy.
d. Reject paid donors.
e. Maintain surveillance for all post-transfusion cases including registering
of all persons who donated blood for each case and notify blood banks
about them
B) Secondary preventive measures:
I. Screening for early case detection:
Serological testes for syphilis and HIV
(Eliza) HB ( HB markers) should be carried for risk groups :
» Women during premarital or antenatal care
» Prisoners
» Health care workers
» Drug addicts
» Blood donors.
» Contacts of patients with STDs
II Contact tracing: It is the technique to detect, identify, diagnose, and locate
the sexual partners to treat them to prevent the spread of infection
III. Treatment should be started immediately even before the results of
laboratory tests.
Relative Efficiency of HBV, HCV, HIV Transmission
by Type of Exposure
Type of exposure Efficiency of transmission
to infected source HBV HCV HIV
Transfusion ++++ ++++ ++++
Injecting drug use ++++ ++++ ++++
Needle stick +++ + one month. • Persistent cough> one month.
• Prolonged fever> one month • Generalized pruritic dermatitis.
• Episodes of Herpes zoster.
• Chronic Herpes simplex
infection
Oral leucoplakia (OHL)
is a very typical clinical picture
in HIV-infected persons
Early Kaposi’s sarcoma in the skin.
Kaposi’s sarcoma in the palate of an AIDS patient who survived
.for about six months
.Advanced Kaposi’s sarcoma with marked lymphostatic oedema in a patient’s face
Confirmed Case
A suspected case can be confirmed by the following laboratory tests:
• Diagnosis of HIV infection: Detectable antibodies appear after a period
ranging between three weeks and 6 months and remain for life. ELISA is
the most frequently used diagnostic test. If the test is positive it should be
confirmed by another more specific test as Western blot.
• Diagnosis of opportunistic infections
• An opportunistic infection:
It is an infection caused by pathogens that usually do not cause disease in a
healthy immune person
A defective immune system represents an "opportunity" for the pathogen to
infect.
The opportunistic infections include:
•Pneumocystis carinii
•Candida albicans
•Staphylococcus aureus
•Streptococcus pyogenes
•Pseudomonas aeruginosa
•Toxoplasma gondii
•Cytomegalovirus
Descriptive epidemiology
Place
HIV/AIDS were wide spread in many countries before the first cases
were reported in 1981.
Current estimates suggest that about 39 million people worldwide are
infected with HIV since the start of epidemic.
Person:
- Most cases have occurred among sexually active person aged 20- 49 years
- It is more among males
- Women get the infection easier than men for the following reasons:
Woman is a receptive partner who has a large mucosal surface;
Semen contains a larger concentration of HIV than vaginal secretions.
They are more likely to receive blood transfusions.
Current Global Estimates of HIV Statistics
39.5 million
90%
4.3 million
2.9 million
People Living New Deaths Percent w/HIV
with HIV/AIDS Infections (in 2006) Who Don’t Know
(as of end 2006) (in 2006) They’re Infected
*Sources: UNAIDS, 2006 AIDS Epidemic Update, December 2006; UNAIDS, 2006
Report on the Global AIDS Epidemic, May 2006; WHO/UNAIDS, Progress in Scaling
Up Access to HIV Treatment in Low and Middle-Income Countries, June 2006, Fact
Sheet, August 2006.
Incubation Period:
• The symptoms and signs appear after about 6 months,
• Asymptomatic infected person (HIV positive) may stay free up to 20
years without clinical manifestations.
This depends on : age of the patient, health status and immune
response.
Cycle of infection:
Agent:
Human immunodeficiency virus (HIV)
There are two types
The virus is easily destroyed outside the human body by, drying or disinfectants
i.e. sodium hypochlorite with 0.1- 0.5% ,available chlorine (common household
bleach).
Reservoir:
Case (AIDs) or carriers (HIV infected persons from the time of infection until
their death )
Source of infection: •
The virus is found in
great concentration in
» Blood Semen ,C.S.F
lower concentration in
» Tears, Saliva, Sweat, Breast milk, colostrums, Urine, cervical
&vaginal secretion,
Only blood and semen have been documented to transmit the virus
Mode of transmission
Sexual intercourse with an infected partner. In 90% of cases
Parenteral: Infected blood and blood products (5% of cases), by whole blood,
RBCs, platelets, plasma, and clotting factors.
No evidence of transmission by albumen or immuno-globulins or
hepatitis B vaccine because the manufacturing process of these items kills
the virus.
Contaminated needles, syringes (addicts) and needle stick (0.4%) or
any skin piercing instrument (ear piercing, tattooing, or scarification) if the
instrument is not sterile
Organ transplantation
Transmission of HIV infection from infected mother to her child . The virus
cross the placenta to the fetus before birth or during birth or after birth through
breast- feeding
HIV is not transmitted by:
•Coughing, sneezing, shaking hands,
•Sharing a drinking glass, plates or spoons & forks, kissing
•Insect bites
•Living in the same household,
•Working with an AIDS patients or HIV positive person,
•or Sharing the same toilets or baths
Susceptibility
Susceptibility is general.
The immune system is destroyed by the virus.
There are several vaccines under development.
Prevention
Apply the primary and secondary measures for prevention of STDs
Control:
Notification: Notification of HIV & AIDS cases.
Isolation of AIDS and HIV infected person is not required as transmission
occurs through limited modes of transmission. Special measures for universal
precautions should be taken when handling the blood of such cases, during
surgical procedures, and deliveries of infected pregnant.
Concurrent& terminal disinfection: Contaminated surfaces and articles soiled
with blood of infected person should be cleaned and then disinfected using of
5% sodium hypochlorite.
Infected persons specially pregnant women should be advised on the use of
condom,. refrain from donating blood ,be advised not to share toothbrushes,
razors
Specific treatment: Antiviral drugs These are:
1- Drugs that improve host immune functions
2- Drugs as prophylaxis against the
opportunistic infection.