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LINFECTION A VIH SIDA 2) LES MODES DE TRANSMISSION ET LEUR IMPORTANCE.

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Présentation au sujet: "LINFECTION A VIH SIDA 2) LES MODES DE TRANSMISSION ET LEUR IMPORTANCE."— Transcription de la présentation:

1 LINFECTION A VIH SIDA 2) LES MODES DE TRANSMISSION ET LEUR IMPORTANCE

2 RISQUES TRANSMISSION DE LINFECTION HIV T SANGUINE PAR TRANSFUSION# 100% T MERE-ENFANT20 à 30% T MERE-ENFANT(AVEC ARV)5 à 10% T PAR ALLAITEMENT10 à 15% T PAR ECHANGE DE SERINGUE1 à 10 p1000 T PAR AES3 p1000 T PAR RAPPORT SEXUEL HOMOSEXUEL5 à 8 p1000 HETEROSEXUEL(FEMME)2 à 3 p1000 HETEROSEXUEL(HOMME) 1 p1000

3 PRESENCE DU VIRUS HIV DANS LES VOIES GENITALES SPERME 30 à 60% (1/3 à 1/2) COL30 à 50% (1/3) VAGIN15% (1/6)

4 DENSITE DES CELLULES CIBLES POTENTIELLES AU VIH DANS LES MUQUEUSES GENITO-URINAIRE,ANALE,RECTALE ET ORALE,ET DISTRIBUTION DES CELLULES M. CELLULES RF c + CELLULES EPITHELIALES HLA II+ CELLULES MONONUCLEEES CD4 + (LAMINA PROPRIA) CELLULES DE LANGERHANS CELLULES M MUQUEUSE VAGINALE EXOCERVICALE ZONE DE TRANSITION (CERVIX) MUQUEUSE ENDOCERVICALE MUQUEUSE PREPUCIALE à à +++- MUQUEUSE URETHRALE MASCULINE + ±+ -- MUQUEUSE ANALE NRNR++++- MUQUEUSE RECTALE MUQUEUSE ORALE (1) - absent + rare++ présent +++ abondant (1) NR non rapporté (1) Les amygdales posséderainet de rares cellules M

5 TRANSMISSION PROBABILITY BY SEXUAL INTERCOURSE (PER 1000 ) POPULATION PRIMARY INFECTION ASYMPTOMATIC STAGE SYMPTOMATIC STAGE ALL COUPLE 2,10,71,5 MALES-FEMALES VAGINAL INTERCPURSE ANAL INTERCOURSE 2,90,81260,90,7171,30,6321 FEMALES-MALES -0,43

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7 LOCAL AND GENERAL RISK FACTORS FOR HIV SEXUAL TRANSMISSION Infection Stage Primary Infection ++ Primary Infection ++ Severe Immune depression + Severe Immune depression + Clinical stage 3 or 4 + Clinical stage 3 or 4 + High viral load + High viral load + Chronic stimulation of immune System (infections? STDs?)+ HIV coreceptors abnormalities - Age : Women 45 years?+ Girls < 13 years?+ Girls < 13 years?+ GENERAL COFACTORS INFECTIVITY SENSITIVITY

8 LOCAL AND GENERAL RISK FACTORS FOR HIV SEXUAL TRANSMISSION LOCAL COFACTORS STDS ++ STDS ++ BACTERIAL VAGINOSIS ? + BACTERIAL VAGINOSIS ? + GENITAL TRACT INFLAMMATION + + GENITAL TRACT INFLAMMATION + + CERVICAL ECTOPY ? + CERVICAL ECTOPY ? + LACK OF CIRCUMCISION ? + LACK OF CIRCUMCISION ? + HIV VARIANTS +(?) HIV VARIANTS +(?) LOCAL CONTRACEPTION LOCAL CONTRACEPTION I U D - ±(?) I U D - ±(?) GENERAL COFACTORS INFECTIVITY SENSITIVITY

9 PRESENCE DU VIRUS HIV DANS LES VOIES GENITALES Variations avec CD4 ± pas de parallélisme parfait Avec Tt ARV ± pas de obligatoirement (secteur différent) (dailleurs le virus sanguin et le virus sexuel ne sont parfois pas totalement identiques) AVEC DEFICIT VITAMINE A ( AU NIVEAU DU COL) x 12 – ( selon lintensité du déficit )

10 HIV/ STD and risk attributable (MEDIAN AND RANGE) GENITAL ULCERATION 4,7 (3,3-18,2) SYPHILIS 3 (2-9,9) GENITAL HERPES3,3 (1,9-8,5) CT –INFECTION4,5 (3,2-8,7) GONOCOCCAL INFECTION 4,5 (3,5-8,9) TRICHOMONIASIS1,9 ANO GENITAL WARTS3,7 OR ICAAC- 1993

11 Role des MST dans la transmission du VIH Role épidémiologique Fonction de lincidence Syndrome / Maladie Estimation du risque MoyenneIntervalle Chancre mou 4,73,3-18,2 Syphilis (sérologique) 3,02,0-9,9 Herpès Génital 3,31,9-8,5 Chlamydia4,53,2-5,7 Gonorrhée4,73,5-8,5 Trichomonase2,7? Condylomes3,7? Source : Wasserheit J;Holmes K.K.; En Germain A. et coll. : Reproductive tract infections

12 Manifestations liées au MST indiquant une excrétion génitale accrue de VIH Sécrétions cervico-vaginale Cervicite mucopurulente Cervicite mucopurulente Ulcération cervicale Ulcération cervicale Ulcération vaginale Ulcération vaginale Leucocytes Leucocytes N. gonorrhoea N. gonorrhoea C. trachomatis C. trachomatisSperme Urétrites Urétrites Leucocytes Leucocytes N. gonorrhoea N. gonorrhoea Source :OMS Dpt VIH/SIDA

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19 HETEROSEXUAL TRANSMISSION COMPARAISON EUROPA/ AFRICA The risk of contamination for a young african Is 500 fold higher (1/5-10) than in Europe (1/ ) than in Europe (1/ ) CAUSES= STD median RR:4 PREVALENCE 10 TO 15 FOLD HIGHER (x50) PREVALENCE 10 TO 15 FOLD HIGHER (x50) =Multiple silmultaneous partnership (x10) =Multiple silmultaneous partnership (x10) =Role of some HIV1 subtypes such as C or E (?) =Role of some HIV1 subtypes such as C or E (?)

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21 HOMMES FEMMES FILLESGARCONS 15 à 49 ANS 15 à 49 ANS 15 à 19 ANS 15 à 19 ANS KISUMU NDOLA Source –différence dans la propagation du VIH dans quatre villes dAfrique subsaharienne SEROPREVALENCE COMPAREE SELON LES SEXES ET LAGE A KISUMU (KENYA) ET NDOLA (ZAMBIE) EN %

22 Probability of HIV-1 TRANSMISSION PER COITAL ACT IN MONOGAMOUS,HETEROSEXUAL,HIV-1-DISCORDANT COUPLES IN RAKAI,UGANDA SUMMARY BACKGROUND the probabilityof HIV-1 transmission per coital act in representative African populations in unknown. We aimed to calculate this probability overail,and to estimate how it is affected by various factors throught to influence infectivity. Methods 174 monogamous couples,in wich one partner was HIV-1 positive,were retrospectively identified from a population cohort in RAKAI,OUGANDA.Frequency of intercourse and reliability of reporting within couples was assessed prospectively. HIV-1 seroconversion was determined in the uninfected partners,and HIV-1 viral load was measured in the infected partners. RESULTS the mean frequency of intercourse was 8-9 per month,wich declined with age and HIV-1 viral load.Members of couples reported similar frequencies of intercourse. The overail unadjusted probability of HIV-1 transmission per coital act was (95% CI ). Transmission probabilities increased from per act at copies/ml or more (p=0.002) and were with genital ulceration versus without (p=0.02). Transmission probabilities per act did not differ significantly by HIV -1 subtypes A and D,sex, STDs,or symptoms of discharge or dysuria in the HIV-1 positive partner

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25 ASSOCIATION BETWEEN METHOD OF CONTRACEPPTION AND HIV-1 SEROCONVERSION HAZARD RATIO 95 % CONFIDENCE INTERVALP MODEL 1 (UNIVARIATE) None/ tubal ligation1.0 DMPA ORAL CONTRACEPTIVES LOW-DOSE HIGH-DOSE IUD MODEL 2 (MULTIVARIATE) contraceptive method None/ tubal ligation1.0 DMPA ORAL CONTRACEPTIVES LOW-DOSE HIGH-DOSE IUD

26 COMPLICATIONS OF USE OF INTRAUTERINE DEVICES AMONG HIV-1 INFECTED WOMEN. (Samuel K Sinei,Charles S Morrison,Christine Sekadde-Kigondu,Melissa Allen,Donald Kokonya) SUMMARY, BACKGROUNDA: WHO expertgroup and the international planned Parenthood Federation recommend against use of intrauterine devices(IUDS) in HIV 1 infected women based on theoreticalconcerns about pelvic infection and increased blood loss.We investigated whether the risk of complications after IUD insertion is higherin HIV 1 infected women than in non-infected women. METHOD 649 (156 HIV 1 infected 493 non infected) women in NAIROBI,KENIA,who requested and met local eligibility criteria for insertion of an IUD were enrolled.We gathered informationon IUD related complications, incluning pelvic inflammatory disease,removals due to infection,pain,or bleeding expulsions,and pregnancies at1and 4months after insertion.Patients HIV 1 status was masked from physicians. FINDINGS Complications were identified in 48 of 615 women ( %- HIV 1 infected women, %-non infected).Incident pelvic inflammatory disease (two - 1.4%-HIV 1 infected, one -0.2%-non infected) and infected related complications (any tenderness,removal of IUD for infection or pain; (ten-6.9% HIV 1 infected, %-non infected) were also rare and similar in the two groups.Complication rates were similar by CD4 (immune) status.Multivariate analyses suggested no association between HIV 1 infection and increased risks for overall complications (odds ratio % CI ) or infection-related complications ( ). adjusted for marital status,study site,previous IUD use,ethnic origin,and frequency of sexual intercourse,but a slight increase cannot be ruled out. INTERPRETATION Our data suggest that IUDS may be a safe contraceptive method for appropriately selected HIV 1 infected women with continuing access to medical services

27 MALE CIRCUMCISION, SEXUALLY TRANSMITTED DISEASE, AND RISK OF HIV A cross-sectional study in KIGALI,the capital of RWANDA, with 837 married men who volunteered for HIV testing and counselling. Despite the low-risk profile, uncircomcised men had a higher prevalence of HIV infection than circumcised men (29% versus 21% HIV positive, p=0.02), which was most marked in men reporting five or more lifetime sex partners (36% versus 23% HIV positive,p=0.005) or contact with prostitutes (35% versus 23% HIV positive, p=0.009). Circumcision remained a predictor of HIV infection in multivariate analyses (multivariate odds ratio 1.69, 95% confidence interval ( ).

28 THE ASSOCIATION BETWEEN LACK OF MALE CIRCUMCISION AND RISK FOR HIV INFECTION: A REVIEW OF THE EPIDEMIOLOGICAL DATA Thirty epidemiological studies identified in the literature that investigated the association between male circumcision status and risk for HIV infection were reviewed. RESULTS: EIGHTEEN cross-sectional studies from six countries reported a statistically significant association, fout studies from four countries found a trend toward an association. Four studies from two countries found no association. Two prospective studies reported significant associations, as did two ecological studies.In studies in which significant associations were demonstrated, measures of increased risk ranged from 1.5 to 8.4. The groups in which positive associations were found included sexually transmitted disease(STD) clinic and hospital patients, outpatient clinic and HIV screening clinic attenders, long-distance truck drivers and general community members.

29 MUCOSAL AND SYSTEMIC HIV-1 SPECIFIC IMMUNITY IN HIV- 1 EXPOSED BUT UNINFECTED HETEROSEXUAL MEN MUCOSAL AND SYSTEMIC HIV-1 SPECIFIC IMMUNITY IN HIV- 1 EXPOSED BUT UNINFECTED HETEROSEXUAL MEN BACKGROUND: Despite multiple, repeated exposures to HIV -1,some individuals never seroconvert. Mucosal and systemic immune correlates of this condition have been analysed in HIV-1 exposed women but no data are available concerning mucosal immunity and HIV -1 specific immune responses in exposed but uninfected men. DESIGN: We analysed cellular and humoral immune parameters in peripheral lymphocytes,seminal fluid and urethral swabs of 14 recently HIV -1 exposed seronegative (ESN) heterosexual men,seven HIV seropositive patients and seven healthy controls. RESULTS: HIV1 specific IGA were detected in urethral swabs of 11 out 14 ESN and of six of seven HIV seropositive patients ; Env- and Gag specific IFNγ producing CD4 and CD8 peripheral lymphocytes were present in ESN and HIV seropositive patients; seminal lymphocytes, but not peripheral blood lymphocytes, of ESN were enriched in actived populations (CD8CD38RO and CD4CD25). P24-specific cytotoxic T lymphocytes were correlated with the percentage of CD4 in the HIV seropositive partners. High urethral concentrations of HIV1 specific IgA were seen in those ESN with the most recent unprotected sexual episode. CONCLUSIONS: this is the first report of HIV specific mucosal immunity in ESN men.These data add to the body of knowledge of the immune correlates present in exposed, uninfected individuals and might be important in vaccine design. Sergio Lo Caputo,Daria Trabattoni,Francesca Vichi,Stefania Piconi,Lucia Lopalco,Maris Luisa Villa,Franscesco Mazzotta And Mario Clerici.

30 Plan de lintervention de Mwanza Formation et supervision Formation et supervision Distribution de médicaments Distribution de médicaments Education sanitaire sur la demande de soins Education sanitaire sur la demande de soins Source :OMS Dpt VIH/SIDA


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