Sexually transmitted diseases STD sexually transmitted infection (STI)
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What is STD (STI)? Why it is important? Commonest complications Classification(Etiological & Syndromic ) Diagnosis Syndromes & the STD causing them How are STD transmitted Gonorrhea, Non-specific urethritis, Chlamydia infection & AIDS*
STI is an illness that has a significant probability of transmission between humans by means of human sexual behavior. While in the past, these illnesses have mostly been referred to as STDs or VDs STD are very common. The most widely known are gonorrhea, syphilis and AIDS but there are more than 35 MO transmitted by sexual contact. WHO: > 330 million new cases/yr. About 1 million infections/day
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Why it is important? 1. Disease burden. 2. Links between STD & HIV. 3. Serious complication.
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STD can be devastating; in women they can be fatal. Commonest complications include:Infertility; ♀& ♂Blinding eye infections or pneumonia in infantsSepsis, ectopic pregnancy and cervical cancer→ deathSpontaneous abortion, adverse pregnancy outcomes. Urethral strictureSocial consequences *
Etiological classification of STDs:
Bacterial infections N. gonorrhea (G.C) T. pallidum (syphilis) H. ducreyi (chancroid) Group B streptococci Viral infections HIV Hepatitis B virus Herpes simplex v. Human papiloma (HPV) Molloscum contagosumParasitic infections T. vaginalis Pediculosis Scabies Chlamydial infections Non-specific urethritis (non-gonococcal urethritis) NSU Lymphogranuloma vinerum Chlamydia trachomatis Fungal infection Candida albicans Mycoplasma M. hominis (NSU)
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Syndromes & the STD causing them
Syndrome
Cause of STD
Urethral discharge (men)
Gonorrhea Chlamydial infection
Vaginal discharge
Trichomoniasis Bacterial vaginosis Candidiasis Gonorrhea Chlamydial infection
Ulcer/s
Syphilis Chancroid Hs
Lower abdominal pain
Gonorrhea Chlamydial infection Anaerobic bacteria
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How are STD transmitted: 1- Human sexual behavior, unprotected 2- Transfusion or contact with blood (syphilis, HIV). 3- Mother-to-child: pregnancy (syphilis, HIV, HB), at delivery (gonorrhea &Chlamydia, HIV), or after birth ( breastfeeding) (HIV, HB). 4- Some STIs can also be transmitted via the use of IV drug needles after its use by an infected person.
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Gonorrhea45% of G. patients have also Chlamydial infectionMale → Some may have no symptoms at all. However, some have signs or symptoms that appear two to five days after infection; symptoms can take as long as 30 days to appear(include a burning sensation when urinating, or a white, yellow, or green discharge from the penis). Gonorrhea may complicated with orchitis, epididymitis and proctitis. *
Female → 80 – 90 % asymptomatic (source of infection), only 10% vaginal discharge, bartholinitis, cervicitis → 20% uterine invasion →endomateritis and salpingitis, pelvic inflammatory disease (PID)& urethritis. *
Systemic complications: 1. Ophthalma neunaturum & conjunctivitis. 2. Pneumonia and pharyngitis. 3. septicemia, arthritis, endocarditis and other.
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Gonorrhea Agent: N. gonorrboeae Communicability: Remain infectious for months if unRx Effective Rx ends communicability within hours. Treatment: ciprofloxacin 5oo mg single dose or spectinomycine 2 gm IM single dose + Doxycycline 100 mg / twice/ 7 days or erythromycin 500 mg *4 / 7days
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Non-specific urethritis (non-gonococcal urethritis) NSUBacterial; The most common bacterial cause of NGU is chlamydia trachomatis 50 – 60 %, but it can also be caused by Ureaplasma urealyticum 10-20%, Haemophilus vaginalis, and Mycoplasma genitalium. Viral; Herpes simplex virus (rare), Adenovirus, Parasitic; Parasitic causes include Trichomonas vaginalis (rare). Noninfectious; Urethritis can be caused by mechanical injury (from a urinary catheter or a cystoscope), by an irritating chemical (antiseptics or some spermicides). *
Chlamydial infection Its an obligate intracellular bacteria, sensitive to broad spectrum AntibioticsC. psittaci → PsittacosisC. trachomatis:TrachomaGenital infection (NSU in male and cervical infection in female) same presentation as G.CC. conjunctivitisInfant pneumoniaLymphogranuloma venerium (other serotype)C. pneumoniae → pneumonia *
Treatment ; is based on the prescription and use of the proper antibiotics depending on the strain of the ureaplasma. Because of its multi-causative nature, initial treatment strategies involve using a broad range antibiotic that is effective against chlamydia (such as doxycycline). It is imperative that both the patient and any sexual contacts are treated.
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AIDS
*Spectrum of diseases caused by HIV infection
ARCAIDS
Initial inf.
asymptomatic
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AIDS ; Its 1st recognized 1981. AIDS reduces the body’s immunity and ability to fight disease. People with HIV/AIDS are susceptible to problems such as pneumonia, tuberculosis, certain tumors, and diarrhea (bacterial pneumonia is one of the commonest presentation) HIV+ person can pass HIV to others. Over 90% of HIV infection; develop AIDS.CFR of unRx AIDS is 80 -90 %. Die within 1-3 year. *
AIDs:Depletion of T-helper lymphocytes (CD4)HypergammaglbulinaemiaOpportunistic infection (e.g. Pneumocystis carinii) &Kaposi’s sarcoma . Africa –GI system and TBMay include:Fever LymphadenopathyNight sweatingHead ache &cough AIDs dementia 1/3 patient if progressive incontinence ¶plegia *
HIV +ve remain +ve life long No vaccine has developed & fully tested yet (under trials).
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DxClinicalSerological:HIV AB detected within 1 -3 months after infection by ELISA and Western blot test. This gap time called window period (i.e. from infection and before detection of AB). Some time we repeat test for conformationvirus isolation CBP: LymphopeniaAnemiaThrombocytopenia↑ ESR *
HIV enzyme-linked immunosorbent assay (ELISA)
Screening test for HIV (Sensitivity > 99.9%)Western blot
Confirmatory test (Specificity > 99.9%) (when combined with ELISA)
HIV rapid antibody test
Screening test for HIV Simple to perform
Absolute CD4 lymphocyte count
Predictor of HIV progression Risk of opportunistic infections and AIDS when <200
HIV viral load tests
Best test for diagnosis of acute HIV infection Correlates with disease progression and response to HAART
Blood Detection Tests
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Diagnosis; WHO disease staging system CDC classification system HIV test WHO disease staging system Stage I: HIV infection is asymptomatic and not categorized as AIDS Stage II: includes minor mucocutaneous manifestations and recurrent upper respiratory tract infections Stage III: includes unexplained chronic diarrhea for longer than a month, severe bacterial infections and pulmonary tuberculosis Stage IV: includes toxoplasmosis of the brain, candidiasis of the esophagus, trachea, bronchi or lungs and Kaposi's sarcoma; these diseases are indicators of AIDS.
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Infectious agent: Human immunodeficiency virus (HIV)A retro-virus, HIV-1 and HIV-2.HIV-2 less pathogenic, slower disease progression and lower rates of mother to child transmission.Replicate in actively dividing T4 lymphocyte Can destroy T4 (helper cells ) which plays key role of regulating the immune system Can spread through the body & pass blood –brain barrier Easily killed by ether, acetone, ethanol 20%Relatively resist UV & ionizing radiation *
Total: 34.0 million [31.6 million – 35.2 million] Europe2.3 million[2.1 million – 2.5 million] Africa22.9 million[21.7 million – 24.2 million] South-East Asia3.5 million[3.0 million – 3.9 million] Western Pacific1.3 million[1.1 million – 1.5 million] Americas3.0 million[2.6 million – 3.5 million] Adults and children estimated to be living with HIV, by WHO Region, GLOBAL HIV/AIDS RESPONSE Epidemic update
Eastern Mediterranean560 000[410 000 – 790 000] *
Total: 2.7 million [2.4 million – 2.9 million] Europe190 000[150 000 – 230 000] Africa1.9 million[1.7 million – 2.1 million] South-East Asia210 000[180 000 – 260 000] Western Pacific130 000[88 000 – 190 000] Americas170 000[120 000 – 240 000] Estimated number of adults and children newly infected with HIV, by WHO Region, GLOBAL HIV/AIDS RESPONSE Epidemic update
Eastern Mediterranean82 000[54 000 – 130 000] *
* 3. Occurrence:
4. Reservoir: Humans.5. Mode of transmission: HIV is transmitted by:Sexual rout – Most common (homo, heterosexual, vaginal, anal or oral sex)Blood &blood productsMother to her child (intrauterine, labor and milk). *Blood Whole blood, platelets, factor 8 &9, plasma. No evidence of risk for albumin and immunoglobulin Risk of transmission from infected one pint of blood is > 95% and it is dose related. Risk of skin piercing is much less than of blood transfusion
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SexualRisky behaviors:The risk of transmission of HIV via sexual intercourse is much lower than other STD.every single act of unprotective intercourse with HIV infected person → 1 % risk of infection to the partner, however this risk increased by:Presence of other STD specially ulcerative types as chancroid →2-5 times, syphilis → 3-9 timesGender: Male → female twice female → male due to higher concentrations of HIV in semen than vaginal secretions & larger vaginal surface area *
Age of uninfected partner: Female > 45 years → high risk due to thin mucosaAdolescent girls high risk due to less effective cervix barrierHigh risk in very early (window period) & very late infections. Because level of virus in blood is higher than other times.Type of sexual act: anal sex → Higher risk → abrasions/ trauma. Also during menstruationLow risk in circumcised males (8 folds in uncircumcised) *
VerticalPlacenta , delivery & breast feeding.Risk is up to 30%. Rx of infected pregnant with zidovudine → marked decrease of infant infection.Risk increase in early & late infections &when there is crakes in the nipple, prematurity (<34W), maternal anemia and chorio-amnitis. *
HIV is not transmitted by:Casual contacts as in work , school,…Hand shaking &touchesSneezing &coughingInsectsFood /water &cups /spoonsBathes /lavatoriesSwimming poolsSecond hand clothingTelephonesThe virus found occasionally in saliva, tears, urine and bronchial secretion but transmission is not reported after contact with these secretions. *
6. I.P : variableHIV → AIDS < 1 year – 15 years or longerIn infants shorter I.P than adults7. Period of communicability:Unknown, early after onset of HIV infection → through out life.8. Susceptibility: general + risky behavior *
9. Method of control:
A- Preventive measures: HIV/AIDS prevention programs can be effective only with full community and political commitment to change and/or reduce high HIV-risk behavior. Health education of public and schools Avoid extra marital sexual intercourse, otherwise use condoms. Adequately sterilization of syringes and needles and lancets, use disposable equipment whenever possible, wear gloves, eye protection and other protective equipment.*
A- Preventive measures: In blood bank, all donors should be tested for HIV AB; reject all donors with a: Risky persons History of injecting drug users or drug addicts. WHO recommends immunization of asymptomatic HIV-infected children with routine schedule of vaccinations; those who are symptomatic should not receive BCG vaccine.
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B- Control of patient, contacts and environment:
Reporting : is obligatory in most of countries Isolation: for HIV +ve individuals is unnecessary, ineffective and unjustified. universal precautions to prevent exposures to blood and body fluids for all hospitalized patients. Disinfection: of equipment contaminated with blood or infectious body fluids. Quarantine: not applicable. Patients and their sexual partners should not donate blood, plasma, organs or breast milk for human milk banks.*
Immunization of contacts: not applicable Notification of contacts and source of infection: the infected patient should ensure notification of sexual and needle sharing partners whenever possible.
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Specific treatment: Prophylactic Rx of P. carinii pneumonia by methoprim. Check for TB infection. Antiretroviral treatment (ARV): complex, combination of drugs, drugs are toxic and treatment must be for life. It suppress viral replication and start the Rx aggressively.
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Typical regimens consist of two; nucleoside analogue reverse transcriptase inhibitors (NARTIs) plus either a protease inhibitor or a non-nucleoside reverse transcriptase inhibitor(NRTIs) should be started (zidovudin &lamivudin +indinavir).
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Post exposure prophylaxis after accidental exposure to blood → (zidovudine + lamivudine) 4weeksFor fetus of infected mother (prevention in the newborn): zidovudine(ZVD) At the beginning of 2nd trimester, during labor and post-delivery (Cs is advised) →↓risk to 8.3%. *