HIV SLIDES by apurwa shatri in microbiology

Slides of HIV

1. Human immunodeficiency virus Presented by – Renuka Sahu (89 ) GUIDED BY:- Rishikesh Shrivastav (90 ) MRS. ANWARI TAYABBA ma’am Ritik Sahu (91) Rituraj Tandan (92) Riya Sai Paikra (93)

2. CONTENT Introduction Epidemiology Risk groups Pathogenesis Clinical features Lab diagnosis Treatment and prophylaxis

3. INTRODUCTION Human immunodeficiency virus is a type of virus that specially targets white blood cells called HELPER T CELLS (CD4 CELLS). It belongs to family RETROVIRIDAE. Out of which two genera are pathogenic to human : Genus Lentivirus Genus Deltaretrovirus ORIGIN : HIV in human are accquired from chimpanzee by cross species infection of simian counterpart of HIV

4. STRUCTURE OF HIV

5. STRUCTURE OF HIV Envelope : HIV is an enveloped virus. The envelope is made up of: Lipid part : It is host cell membrane derived Protein part : It has two components: 1 Glycoprotein : ( gp 120)-They are projected as knob like spikes on the surface . 2. Glycoprotein : ( gp 41)-They form anchoring transmembrane pedicles.

6. Nucleocapsid : Capsid is bullet in shape and made up of core protein. There is a dense cylindrical inner core which encloses: ■RNA: Two identical copies of single-stranded positive sense linear RNA ■ Viral enzymes such as reverse transcriptase, integrase and proteases which are closely associated with HIV RNA.

7. HIV GENES HIV contains three structural genes - gag, pol, and env and six non-structural or regulatory genes. Structural Genes GAG gene -The gag gene codes for the core and shell of the virus. It is expressed as a precursor protein, p55* which is cleaved into three proteins: p18-constitutes the matrix or shell antigen p24 and p15-constitute the core antigens.

8. The POL gene codes for viral enzymes such as reverse transcriptase, protease and integrase. It is expressed as a precursor protein, which is cleaved into proteins p31 (integrase), p51 (reverse transcriptase) and p66

9. The ENV gene codes for the envelope glycoprotein (gp160), which is cleaved into two components: 1. gp120 : It is the main receptor of HIV that binds to CD4 molecules on host cell to initiate the infection 2. gp41 : It is the fusion protein. Unfortunately, envelope proteins happen to be the major target against which antibodies are produced. Hence mutations in env gene are the main reason which explains why: ■HIV evades the host's immune response ■Vaccination against HIV is extremely difficult .

10. NON STRUCTURAL GENE Essential regulatory genes : tat (transcriptional transactivator ), nef (negative factor) rev genes Accessory regulatory genes : vif (viral infectivity factor), upr and upu genes .

11. TYPES OF HIV Based on sequence difference in env gene, HIV comprises of two types : HIV 1 HIV 2

12. TYPES OF HIV HIV 1 Chimpanzee were the source of HIV-1 VIRUS from chimps to human. It is divided in 3 distinct group :- (M, N ,O) M' is the dominant group worldwide. It comprises of eleven subtypes or " clades " (A-K). HIV-1 subtypes do not vary in pathogenesis but they differ in geographical distribution and transmission

13. TYPES OF HIV GEOGRAPHICAL DISTRIBUTION 1. Subtype A is common in West Africa. 2. Subtype B is predominant in Europe, America, Japan, and Australia. 3. Subtype C is the most common form worldwide. HIV-2 1. It comprises of eight subtypes (A-H); they are mainly confined Africa and few other places including India. 2. Group A is the most common form

14. TYPES OF HIV NOTE : HIV-2 is less easily transmitted. HIV-2 is less pathogenic .

15. - Prevalence and Incidence: There were an estimated 39.9 million people living with HIV at the end of 2023, 65% of whom are in the African Region. In 2023, an estimated 6,30,000 people died from HIV-related causes and an estimated 1.3 million people acquired HIV. - Regional Impact: The African region remains the most severely affected by HIV, accounting for more than two-thirds of all people living with the virus globally. This highlights the need for targeted interventions and resources in these areas. EPIDEMOLOGY OF HIV

16. . EPIDEMIOLOGY OF HIV - Country-specific Data: South Africa has the highest number of people living with HIV, with 7.5 million cases. Meanwhile, Eswatini has the highest prevalence rate in the world at 27%, indicating a significant public health challenge that requires ongoing attention and action. - World AIDS Day: Every year, December 1st is observed globally as World AIDS Day. This day is dedicated to raising awareness, honoring those who have lost their lives to the disease, and promoting efforts to combat HIV/AIDS worldwide.

17. HIV SITUATION IN INDIA - HIV Prevalence: As of the end of 2021, the HIV prevalence among adults in India was reported at 0.21%. This is a significant decrease from the year 2000, when the prevalence rate was 0.54%. This decline reflects the ongoing efforts in HIV prevention and control in the country. - High-Prevalence Regions: The Northeast states of India, particularly Mizoram, Nagaland, and Manipur, have the highest HIV prevalence rates in the country. These regions require focused interventions and continuous monitoring to manage and reduce the spread of HIV.

18. HIV SITUATION IN INDIA - Number of People Living with HIV (PLHIV) : In India, the number of people living with HIV by the end of 2021 was approximately 23.2 lakh (2.32 million). This statistic highlights the importance of continued efforts in treatment and support for those affected. - State-wise Impact: Maharashtra is the most affected state in India regarding the number of people living with HIV. It is followed by Andhra Pradesh, Karnataka, Uttar Pradesh, and Telangana. These states have significant populations affected by HIV and need targeted health policies and resource allocation to address the epidemic effectively.

19. HIGH RISK GROUPS FOR HIV INFECTION Extremely High-Risk Groups: Certain populations are at extremely high risk for acquiring HIV. These include: - Female sex workers who may have multiple sexual partners and inconsistent condom use. - Men who have sex with men (MSM), a group that can be at higher risk due to unprotected anal intercourse. - Hijra/transgender individuals, who often face social stigma and barriers to healthcare. - Intravenous (IV) drug users, who are at high risk due to needle-sharing practices that can transmit the virus. Moderately High-Risk Groups: There are also groups considered to be at moderately high risk of HIV infection, including: - Healthcare workers, who may be exposed to the virus through needle pricks or splash injuries in medical settings. - Hemophiliacs and other recipients of blood products, especially where blood screening is inadequate. - Individuals with other sexually transmitted infections (STIs), as the presence of another STI can increase susceptibility to HIV infection.

20. OPPORTUNISTICS INFECTIONS IN HIV INFECTED INDIVUALS - Tuberculosis (TB): - The most common opportunistic infection in HIV-infected people globally, including in India. TB remains a significant cause of morbidity and mortality in individuals with HIV due to their compromised immune systems. Fungal Infections: - Candidiasis (Oral Thrush): A common fungal infection characterized by white patches in the mouth, often seen in individuals with weakened immune systems. - Pneumocystis jirovecii Pneumonia (PCP): A serious fungal infection that can cause severe respiratory issues in HIV-infected individuals.

21. . - Viral Infections: - Herpes Simplex Virus (HSV) Mucosal Lesions: Painful lesions that occur on the mucosal surfaces, commonly in the mouth or genital area. - Cytomegalovirus (CMV) Retinitis: A viral infection that can lead to vision loss or blindness in those with advanced HIV. - Parasitic Infections : - Cryptosporidium parvum Diarrhea : A parasitic infection that causes severe, persistent diarrhea , particularly in immunocompromised individuals. - Toxoplasma Encephalitis: A parasitic brain infection that can cause severe neurological symptoms in people with weakened immune systems. - Strongyloides stercoralis Hyperinfection Syndrome: A severe and potentially fatal parasitic infection that can spread throughout the body in HIV-infected individuals .

22. AIDS CONTROL ORGANISATION - UNAIDS: The Joint United Nations Program on HIV/AIDS - UNAIDS is a leading global advocate for coordinated action against the HIV/AIDS epidemic. - The organization has launched the 'Fast-Track Strategy , aiming to end the AIDS epidemic by 2030 through a comprehensive approach that includes prevention, treatment, and support services. - NACO: National AIDS Control Organization - NACO is the key organization in India responsible for implementing the country's HIV/AIDS control program .

23. AIDS CONTROL ORGANISATION -The State AIDS Prevention and Control Societies (SACS) are the state-level organizations that implement the National AIDS Control Programme (NACO) in India. Functions of SACS are: Medical and public health services; Communication and social sector services; and Administration, planning, coordination, monitoring and evaluation. The District AIDS Prevention and Control Unit (DAPCU) is the district-level organization for HIV/AIDS in India DAPCU is the eye and ears of NACO and State AIDS Control Societies (SACS) .The major responsibility of DAPCU is facilitation, monitoring and coordination of NACP activities at the district and sub- district level by integrating it with the health system to the extent possible for better synergy and optimal results.

24. KINETICS OF IMMUNE RESPONSE IN HIV Viremia Shortly after HIV enters the body, there is a brief period of high viral load and p24 antigen presence. These levels decrease as the immune response activates. Humoral Response The immune system produces antibodies (IgM, IgA, IgG) against various HIV proteins. Structural Proteins : gag (p15, p17, p24, p55), env (gp41, gp120, gp160), pol (p31, p51, p66) Regulatory and Accessory Proteins: nef , rev, tat, vif , vpu , vpr Immunogenicity Structural proteins are highly immunogenic, leading to strong antibody production. Response to regulatory and accessory proteins is variable .

25. As HIV progresses to AIDS, antibodies to p24 decline while p24 antigen levels increase. Antibodies to env proteins persist throughout the infection. Progression to AIDS

26. PATHOGENESIS OF HIV

27. Sexual Mode – Most common mode of transmission, accounts for 75% of total cases. Heterosexual route is commonest mode Anal intercourse has higher risk of transmission than vaginal intercourse 2) Blood Transfusion – Least common mode(5%) of transmission but risk of transmission maximum 3)Percutaneous/Mucosal – Modes like needle stick(0.3%) injury,injection drug abuse,sharing razors or tattooing etc. Modes of transmission

28. 4) Perinatal Mode – Mother to foetus (20-40%) RECEPTOR ATTACHMENT Main Receptor- HIV enters by binding its gp120 to CD4 receptor on host cell surface. Co-Receptor – Chemokine receptor act as co-receptor by binding to gp120 — CXCR4 - On T lymphocytes CCR5 – On cells of macrophage lineage

29. REPLICATION Fusion- Attachment of receptor & co-receptor to gp120,fusion of HIV to host cell takes place;mediated by fusion protein gp41 Penetration & Uncoating – HIV nucleocapsid enters &after uncoating release two copies of ssRNA,viral enzymes(reverse transcriptase& integrase ). Reverse Transcription- ssRNA gets transcribed to ssDNA by viral RT which act as RNA Dependent DNA Polymerase. ssDNA replicate to form dsDNA by DNA Polymerase. Integration- Viral dsDNA gets integrated into host cell chromosome by viral integrase , this integrated virus known as Provirus.

30. NATURAL COURSE It include following five stages:— Acute Retroviral Syndrome- HIV carried to lymph nodes &other lymphoid tissues HIV destroys infected T cells &spills into bloodstream cause Primary Viremia 2) Asymptomatic Stage(Clinical Latency) - Both cell mediated & humoral immune response activated ,lead to normal CD4 T Cell & viremia drops. Stage of Clinical latency but not microbiological latency. It may last for 10years .

31. 3) Persistent Generalised Lymphadenopathy (PGL)— It is defined as enlarged lymph nodes of more than 1cm size in two or more contagious sites that persist for at lest 3 months. 4) Symptomatic HIV Infection— After variable period of clinical latency,CD4 T Cell level starts falling. Symptoms:– Unexplained diarrhoea (>1month) -Weight Loss (>10%) - Mild opportunistic infection NATURAL COURSE

32. 5) AIDS :- Rapid fall in CD4 T Cells count (<200cells/ µl) High viral load Lymphoid tissue destroyed, replaced by fibrous tissue. Opportunistic infections NATURAL COURSE

33. CLINICAL DIAGNOSIS

34. CLINICAL DIAGNOSIS

35. CASE STUDY A 25 year –old male with history of multiple sex partners is admitted with complaints of unexplained fever, progressive loss of weight, persistent diarrhea and generalized lymphadenopathy for the past 6 months. What is the probable diagnosis?

36. LAB DIAGNOSIS OF HIV Diagnosis of HIV/AIDS is not like other infectious disease. A number of moral, ethical, legal and psychological issues are associated with positive HIV status. The following care should be taken (3Cs) while performing the test for HIV. 3Cs are- 1.Consent 2. Confidentiality 3. Counselling

37. Specific tests for HIV infection- 1.ELISA(takes 2-3 hours) 2.RAPID DETECTION TEST(<30 minutes) Screening tests Supplemental tests 1.Western blot assay 2. Line immunoassay Confirmatory test 1.p24 antigen detection (after 12-26 days of infection)

38. 2.Viral culture-by Co-cultivation technique 3.HIV RNA(best confirmatory method)-can be detected 14 days after infection (a) Reverse transcriptase PCR(RT –PCR) (b) Branched DNA assay (c) NASBA(Nucleic acid sequence based amplification) (c) (d) Real time RT-PCR (for estimation of viral load) 4.HIV DNA Detection: useful for detection of diagnosis of pediatric HIV Non –specific Immunological methods Low CD4 T cell count Hypergammaglobulinemia: (a) Neopterin (b) Beta2-macroglobulin 3. Altered CD4:CD8 T cell ratio

39. 1.SCREENING ASSAYS (a) ELISA Most commonly performed screening tests at blood banks and tertiary care sites Easy to perform, sensitive , specific and cost effective. ELISA KITS: Currently available ELISA kits are of two types- 3 rd generation 4 th generation ( a) ELISA uses recombinant (a)ELISA detects both HIV ab and/or synthetic peptide as and p24 antigen by using antigen to detect HIV ab combination of recombinant and monoclonal antibodies

40. (b) RAPID/SIMPLE TESTS 1.This test generally require less than 30 minutes to perform and do not require special equipment . 2. Work on various principles such as: Dot blot assay (or immunoconcentration or flow through method eg. Tridot tests Immunochromatography(or ICT, lateral flow assay) Particle agglutination assays (using latex, gelatin,RBCs ) Dip stick/Combo tests (enzyme immune assay based tests

41. 2 . SUPPLEMENTAL TESTS These assays are highly specific antibody DISADVANTAGE- Expensive, labor intensive ,need expertise to interpret. Give undeterminant results. WESTERN BLOT Most commonly used supplemental test Works on the principle of immunoblot technique in which it is described that sample containing a mixture of antibodies each targets against different antigen of same microbes. It detects individual antibody separately against antigenic fragments of HIV

42. Antibody against Antigen 1. Antibody to gag gene products (p55,p24,p18,p40) 2.Antibody to pol gene products ( p65/66,p55/51,p31) 3. Antibody to env gene products ( gp 120,gp160,gp41) Antigen antibody complexes are appear in the form of bands on nitrocellulose strip Reactive results are interpreted as per: * WHO Criteria: 2 envelope bands should be present in which gag or pol band either may be present or absent * CDC Criteria: Presence of any two bands out of p24,p41,p120,p160 bands

43. 3. CONFIRMATORY TEST ( a) DETECTION OF p24 CORE ANTIGEN The p24 antigen becomes detectable after 12-26 days of infection and lasts for 3-4 weeks p24 antigen is detected by 4 th generation ELISA It is less sensitive Uses : 1. For confirmation of diagnosis of HIV/AIDS 2. Diagnosis of HIV/AIDS during the window period as well as in the late stage 3. Monitoring the process of HIV infection

44. (b) VIRAL RNA DETECTION 1. Detection of viral RNA is the “gold standard “ method for the confirmation of HIV diagnosis 2. some methods are there which detects viral RNA: Reverse transcriptase polymerase chain reaction ( RT-PCR) Branched DNA assay NASBA Real time RT PCR Some other uses of HIV: Detection of drug resistance genes Sensitive and specific method Diagnosis of HIV during window period

45. (c) DNA PCR 1 . DNA PCR is useful for the diagnosis of pediatric HIV 2. Differentiate latent HIV infection from active viral transcription 3. Useful for viral load estimation, diagnosis of HIV during window period (d) ISOLATION OF VIRUS FROM BLOOD OR TISSUES Co-Cultivation : Co-cultivation is the method which is used for virus isolation. Peripheral blood mononuclear cells from patient and healthy donor Co-cultured Detection of viral RNA or antigen in culture .

46. 4. NON- SPECIFIC /IMMUNOLOGICAL TEST (a) CD4 CELL COUNT: CD4 T cell count is done by flow cytometry method. It is useful for: 1. Assessing the risk of opportunistic infection 2. Initiation of antiretroviral therapy 3.Monitoring the response to antiretroviral therapy. (b) ABNORMAL PROTEINS: Peripheral blood mononuclear cells HIV activated TH1 produces cells Neopterin,beta2-macroglobulin and soluble IL-2 receptors produces (+) IF gamma or IL-2

47. NACO STRATEGY FOR HIV DIAGNOSIS NACO(National AIDS Control Organization,India ) has formulated a strategic plan for HIV diagnosis. The guidelines are as follows: Depending upon the situation the positive result of the first screening test should be considered as such or it ios more confirmed by one or two screening tests. The first screening test is highly sensitive while the second and third screening tests are highly specificity The principles of three screening tests should be different and same kit is not used .

48. TREATMENT TREATMENT Antiretroviral Therapy (ART) - These don’t kill the virus or cure the disease - They have following goals — 1.CLINICAL GOALS - prolongation and improved quality of life 2.VIROLOGICAL GOALS- Reduction of viral load 3.IMMUNOLOGICAL GOALS- Immune reconstition 4. TRANSMISSION GOALS-Reduction of HIV transmission

49. ART GUIDELINES, NACO 2018 Indication to start ART - TREAT ALL irrespective of age ,CD4 count,stage , population or associated OIs. Highly active antiretroviral therapy (HAART) Use of combination of at least three antiretroviral drugs to maximally suppress HIV and stop its progression.

50. NACO recommended first line HAART regimen PRINCIPLE -Three drugs- 2 NRTIs or NtRTI + 1NNRTI - protease inhibitor instead of NNRTI for HIV-2 infection . NACO Recommended FIRST LINE REGIMEN for various situations. MONITORING - CD4 count and viral load has to be monitored every 3 - 6 months to monitor response of treatment.

51. 1. Prophylaxis for pneumocystis pneumonia(PCP) -primary prophylaxis Initiated if - — CD4 count < 350 cells / cmm — WHO clinical stage 3 and 4 - secondary prophylaxis After completion of PCP treatment continued untill CD4 count remains at > 350 cells/ cmm for period of 6 months .

52. 2. Prophylaxis for cryptococcal meningitis -secondary prophylaxis with fluconazole 200 mg daily should be given - continued untill CD4 cell count remains at >200 cells / cmm for a period of 6 months.

53. 3. Isoniazid Preventive Therapy ( IPT) - protect against progression of latent TB infection to active disease. - also prevents TB reinfection after exposure to open case of TB.

54. PROBLEMS pertaining to use of ART - Toxicity and adverse effects of ARTs - High cost of regimen - Risk of development of drug resistance - limited therapeutic options

55. IRIS — Immune reconstituted inflammatory syndrome - As viral load decreases, immune system begins to recover. - so there is exaggerated immune response causing overwhelming inflammatory response that makes symptoms of infection worse.

56. POST EXPOSURE PROPHYLAXIS To reduce the risk of transmission after occuptional exposure . Every hospital to should have nodal centre of PEP management. TL + LR regimen Tenofovir 300 mg + Lemivudine 300 mg , one tablet once daily . Lopinavir 200 mg + Ritonavir 50 mg two tablets , twice daily. Indication If source is unknown / positive for HIV . Duration Should be started within 2 hours of exposure and continued for 28 days.

57. NACO Guidelines to prevent NEONATAL HIV - Newborn babies are initiated on 6 weeks of syrup Nevirapine immediately after birth. - This maybe extended upto 12 weeks if duration of ART of mother is less than 24 weeks. - The baby is also initiated on contrimoxazole prophylaxis at 6 weeks till 18 months .