RETROVIRIDAE GENUS: ONCOVIRUS: HTLV-1 and HTLV-2 SPUMAVIRUS LENTIVIRUS: HIV-1 and HIV-2

Infection Asymptomatic Simptomatic AIDS Seroconversion CD4 Anti-HIV HIV RNA in plasma Weeks > 12 Years Years HIV viral load # copies/ml T CD4 count cels/ml NATURAL HISTORY

LABORATORY METHODS Screening tests: ELISA Agglutination Dot ELISA Ab’s + Ag p24 (Dual tests) Confirmatory tests: Western blot Immunofluorescence RIPA Monitoring tests:Viral Load CD4 count tests Perinatal Diagnosis:PCR IgA Western blot Other tests:HIV Subtypes: ELISA, HMA HIV Genotyping assays PCR HIV-2, ELISA HIV-2 Screening tests: ELISA Agglutination Dot ELISA Ab’s + Ag p24 (Dual tests) Confirmatory tests: Western blot Immunofluorescence RIPA Monitoring tests:Viral Load CD4 count tests Perinatal Diagnosis:PCR IgA Western blot Other tests:HIV Subtypes: ELISA, HMA HIV Genotyping assays PCR HIV-2, ELISA HIV-2 Rapid tests

WHO/UNAIDS STRATEGIES Test objectivePrevalenceStrategy Transfusion/TransplantAllI Epidemiological> 10%I Surveillance< 10 %II Symptomatic> 30%I Diagnosis< 30%II Asymptomatic > 10%II < 10%III Test objectivePrevalenceStrategy Transfusion/TransplantAllI Epidemiological> 10%I Surveillance< 10 %II Symptomatic> 30%I Diagnosis< 30%II Asymptomatic > 10%II < 10%III

WHO/UNAIDS STRATEGIES OBJECTIVE HIV TESTING STRATEGY Reducing Western Blot use Screening test combinations Choose a strategy based on: *Analysis objective *Sensibility and Specificity *HIV Prevalence OBJECTIVE HIV TESTING STRATEGY Reducing Western Blot use Screening test combinations Choose a strategy based on: *Analysis objective *Sensibility and Specificity *HIV Prevalence

FUNCTIONS OF HIV TESTING Screening blood for transfusions Surveillance and monitoring Voluntary counseling and testing Perinatal prevention programs Screening blood for transfusions Surveillance and monitoring Voluntary counseling and testing Perinatal prevention programs

TRADITIONAL DIAGNOSTIC HIV TESTING TRADITIONAL DIAGNOSTIC HIV TESTING High blood volume Equipment (specific) Technically demanding Centralized, time-consuming High blood volume Equipment (specific) Technically demanding Centralized, time-consuming Since inception, testing technology driven by blood needs:

NEW SIMPLE DIAGNOSIS RAPID ASSAYS NEW SIMPLE DIAGNOSIS RAPID ASSAYS Point of service testing Minimal equipment requeriments Straightforward interpretation Immediate test results Low cost Point of service testing Minimal equipment requeriments Straightforward interpretation Immediate test results Low cost

¿ WHAT RAPID TESTS ARE? They are screening tests for HIV antibody detection that produce results very fast (5 to 30 min)

RAPID TESTS 1)Agglutination tests Principle of the test: They use gelatine perticles coated with HIV antigens, neutralized. These particles in the presence of antibodies, form an agglutination net. They was developed for use with serum or plasma. 1)Agglutination tests Principle of the test: They use gelatine perticles coated with HIV antigens, neutralized. These particles in the presence of antibodies, form an agglutination net. They was developed for use with serum or plasma.

PRUEBAS RAPIDAS (Aglutinación de Partículas)

2)Immunodot RAPID TESTS Principle of the test: They are a enzymatic immune assay (EIA) based on specific Ab detection for HIV-1 and HIV-2 with antigens in 2 reaction sites.

RAPID TESTS (IMMUNODOT)

3)Immunochromatography (lateral flow tests) Principle of the test: If the samples contain antibodies against HIV-1 and/or HIV-2, these antibodies will bind to viral antigens coated onto a membrane. The Ag-Ab complex will be visible : blue line on the test Principle of the test: If the samples contain antibodies against HIV-1 and/or HIV-2, these antibodies will bind to viral antigens coated onto a membrane. The Ag-Ab complex will be visible : blue line on the test RAPID TESTS

Immunocromatography PositiveNegativeInvalid test

RAPID TESTS (SAMPLE) RAPID TESTS (SAMPLE) Serum / plasma Whole blood Oral fluid (crevicular) Serum / plasma Whole blood Oral fluid (crevicular)

CONSIDERATIONS Annually are carried out a large number of screening tests Most of them are performed for the first time Many people do not return for their results There is many rapid test available. Most of them with unknown performance Annually are carried out a large number of screening tests Most of them are performed for the first time Many people do not return for their results There is many rapid test available. Most of them with unknown performance

EFFECT OF PREVALENCE According to test specificity HIV Prevalence 10 % 5 % 3 % 2 % 1 % 0.5 % 0.3 % 0.1 % HIV Prevalence 10 % 5 % 3 % 2 % 1 % 0.5 % 0.3 % 0.1 % Predictive Value Positive 96 % 91 % 86 % 80 % 67 % 50 % 38 % 18 % Predictive Value Positive 96 % 91 % 86 % 80 % 67 % 50 % 38 % 18 %

LESSONS LEARNED Both client and staff prefer same-day result. Immediate counseling can be provided Combination-test algorithms yield accurate results Same-day results help clients to receive immediate referrals and services they need Both client and staff prefer same-day result. Immediate counseling can be provided Combination-test algorithms yield accurate results Same-day results help clients to receive immediate referrals and services they need

EPIDEMIOLOGY IN MEXICO REPORTED CASES AND ESTIMATE OF PLWHIV June Reported cases121,718 PLWHIV200,000 Perinatal cases22 New cases1,767 Source: In order to prevent newborn HIV infections one million of pregnant women are tested using rapid tests

CONCLUSIONS Rapid HIV tests are essential for early access to prevention, care and support services Rapid testing and quality counseling is feasible and can help staff to provide immediate care and support Numerous accurate rapid tests exist It is necessary evaluate the performance of the test in our countries Rapid HIV tests are essential for early access to prevention, care and support services Rapid testing and quality counseling is feasible and can help staff to provide immediate care and support Numerous accurate rapid tests exist It is necessary evaluate the performance of the test in our countries

PERSONAL