HIV and TB

1. HIV and TB Colleen Daniels Edwin Bernard

2. What is Human Immunodeficiency Virus? • HIV is a virus that attacks the immune system, our body’s natural defense against illness. The virus destroys a type of white blood cell in the immune system called a T-helper cell, and makes copies of itself inside these cells. T-helper cells are also referred to as CD4 cells. • As HIV destroys more CD4 cells and makes more copies of itself, it gradually breaks down a person’s immune system. This means someone living with HIV, who is not receiving treatment, will find it harder and harder to fight off infections and diseases. • If HIV is left untreated, it may take up to 10 or 15 years for the immune system to be so severely damaged it can no longer defend itself at all. However, the speed HIV progresses will vary depending on age, health and background.   Source: https://www.avert.org/about-hiv-aids/what-hiv-aids Human – means it is a virus that infects humans. Immunodeficiency – means it reduces the immune system. Virus – means that the infection is a virus

3. What is a Virus ? • A virus is genetic organism that can only reproduce inside cells of another living organism. Some viruses are harmless and others can cause illness. Anti-viral drugs are used to treat viral infections. • HIV belongs to a family of viruses called retroviruses. This is why HIV drugs are called antiretrovirals(or ARVs). A retrovirus is a type of virus that needs to make a ‘backward step’ in order to reproduce – hence ‘retro’.

4. What is Bacteria? • Bacteria are single-cell microorganisms. Some bacteria are healthy and help your body. Some bacteria are dangerous and cause disease. • Antibiotic drugs are used to treat bacterial infections. • Examples of bacterial infections that affect people with HIV include tuberculosis, bacterial pneumonia, sinusitis, gonorrhoeaand some skin infections.

5. What is TB? The scientific name for the TB microbe is mycobacterium tuberculosis orMTB Beneath a microscope, it has a long rodlike shape and thick, waxy-looking coat. Bacteria are single-celled organisms which can exist either independently or as parasites (dependent upon another organism for life). TB is a type of mycobacteria myco means “waxy” in Latin and refers to TB’s waxy-looking cell wall. There are 70 different types of mycobacteria

6. Basic facts about HIV • There is effective antiretroviral treatment available so people with HIV can live a normal, healthy life. • The earlier HIV is diagnosed, the sooner treatment can start – leading to better long term health. So regular testing for HIV is important. • HIV is found in semen, blood, vaginal and anal fluids, and breast milk. • HIV cannot be transmitted through sweat, saliva or urine. Source: https://www.avert.org/about-hiv-aids/what-hiv-aids

7. HIV and infection: key facts • The risk of HIV transmission is related to how much virus is in the blood or infectious fluids. • The risk is highest when the viral load is high. Levels of HIV are measured using viral load tests. • Outside the body, HIV in blood or other bodily fluids is thought to die within a minute or so. • HIV is a difficult virus to catch from sexual exposure. But only one exposure is needed to become HIV positive. • HIV is much easier to catch from sharing infected needles or other IV drug taking equipment. This is because there is direct blood-to-blood contact. Source: Treatment Training Manual for Advocates, iBase http://i-base.info/english-treatment-training-manual/

8. HIV and infection: key facts • HIV enters the blood by broken skin or through cells that are close to the surface of the skin. This can include contact with mucous membranes (the type of tissue that lines the inside of the vagina, rectum and inner foreskin). • Without testing, many people with HIV do not know they are HIV positive. • Without treatment (ART), some people (less than 5%) will become ill within 1-2 years. A few people (also less than 5%) can go for 15 years without symptoms. • Although a lot of information about your health and HIV comes from blood tests, less than 2% of the HIV in your body is in your blood. • Most HIV is in your lymph system and lymph nodes. These are the little lumps that sometimes get enlarged in your neck, under your arms, and in the crease between your legs and your body Source: Treatment Training Manual for Advocates, iBase http://i-base.info/english-treatment-training-manual/

9. Natural history of HIV • The natural history of HIV infection has several different stages. These stages include • Infection - This is the point when HIV infects the frst cells. It then takes several hours for these newly infected cells to carry HIV to the lymph nodes. • Seroconversion - After building up in the lymph nodes, the nodes burst sending HIV into the blood. This sends HIV throughout the body. HIV levels (viral load) become detectable in blood and reach very high levels (often millions of copies/mL). • Primary infection - is also called early infection or acute infection. Primary infection describes the first six months after infection. Source: Treatment Training Manual for Advocates, iBase http://i-base.info/english-treatment-training-manual/

10. Natural history of HIV • Chronic infection - describes HIV infection after the first six months. Chronic infection can last for many years. It can take from 2-10 years until the majority of people get symptoms from having a damaged immune system. With ART, chronic infection can be life-long – i.e. 20, 30, or 40 or more years after infection. • Late-stage illness - Late stage infection is the most serious stage and is now more rare. It is only seen in people who do not have access to treatment, who are only diagnosed very late. It is also seen when treatment has stopped working because HIV has become resistant to drugs. • Late stage HIV used to be called AIDS, but the term AIDS is now rarely used. • HIV treatment (ART) prevents progression of HIV disease. Source: Treatment Training Manual for Advocates, iBase http://i-base.info/english-treatment-training-manual/

11. Effect of ARVs on viral dynamics of HIV infection • After starting ART, viral load should go down by at least 90% (1 log) within the first week – mostly in the first few days. • After staring ART, viral load should then become undetectable (less than 50 copies/mL) within three months. • Some people become undetectable after only a month. For some people this takes longer. Source: Treatment Training Manual for Advocates, iBase http://i-base.info/english-treatment-training-manual/

12. More Questions on Antiretroviral Therapy • How do doctors decide which ART to put one on? • WHO Guidance • What is re-infection with HIV? • The relationship between CD4 count and viral load? • How does ART suppress viral load?

13. HIV in Sub Saharan Africa – Past • Once HIV was established in the region in the 1980s rapid transmission rates in the eastern region made the epidemic far more devastating than in West Africa, particularly in areas bordering Lake Victoria. • Accelerated spread in the region was possibly due to a combination of widespread labor migration, high ratio of men in the urban populations, low status of women, lack of circumcision, and prevalence of sexually transmitted diseases. • With a few notable exceptions, the 1980s and 1990s were characterized by an insufficient response to AIDS in Africa by politicians; prevention programs were not making an impact and there was no treatment available.

14. HIV in Sub-Saharan Africa - Present • Trends in new HIV infections in sub-Saharan Africa show a decline by more than 33% from an estimated 2.2 million in 2005 to 1.5 million in 2013, but remain high. The scale up and widespread coverage of ART has led to substantial declines in new HIV infections.  • Disproportionately high HIV prevalence in women and girls suggest lack of appropriate interventions to protect young women and to meet their sexual and reproductive health needs as they prepare for adulthood • Lack of data in marginalized groups such as men who have sex with men, people who inject drugs and sex workers – but emerging data suggests that HIV prevalence is significantly higher in these groups than in the general population

15. HIV in Sub-Saharan Africa • Need to address major challenges in the region • Discriminatory environments and in-country legislation that not only sustain, but fuel the epidemics resulting in extraordinarily high prevalence. • Structural, behavioral and biomedical interventions must be evidence and rights based, are non-discriminatory and gender transformative. • Programs should aim to decriminalize sex work, men who have sex with men and reduce intimate partner violence.

16. What is TB/HIV? • HIV and TB form a lethal combination, each speeding the other's progress. • HIV weakens the immune system. Someone who is HIV-positive and infected with TB bacilli is many times more likely to become sick with TB than someone infected with TB bacilli who is HIV-negative. • At least one-third of the 33 million people living with HIV worldwide are also infected with TB and at greatly increased risk of developing TB disease.

17. TB/HIV • TB is the leading cause of death among people living with HIV. • Almost one in four deaths among people with HIV is due to TB. • Most common presenting illness among people living with HIV, including those who are taking antiretroviral treatment. Source: WHO, 2012

18. What is the difference between TB infection and TB disease? Many people incorrectly use the terms TB infection and TB disease interchangeably. Latent TB infection (aka LTBI) refers to the period of time when the immune system has been successful in containing the TB bacteria and preventing disease. Active TB disease refers to the time when TB breaks out of latency and causes disease.

19. TB-specific CD4 and CD8 T cells travel into the lung to contain TB bacilli and eliminate infected cells. Cytokines (cellular chemical messengers) released by these cells also activate macrophages in a way that helps them break down and dispose of TB (process known as phagocytosis). As a result, instead of being eliminated from the body, the TB microbe is encased in a hard shell, known as a tubercle. Latent TB infection tuberculosis tubercle

20. BCG Vaccine • We still do not understand the basic science of TB, in particular the progression from latent TB infection to active TB disease • Some studies show that the presence of a BCG scar and related TST negative results were not significantly associated with a higher prevalence of LTBI • People who have had the BCG vaccine will often then have a positive result to a TB skin test. This makes it more difficult to establish whether someone has latent TB. This is one of the reasons that the vaccine is not used in some countries.