Human Immuno Virus

HIV *Human Immunodeficiency Virus*:

HIV *Human Immunodeficiency Virus* By : Motlagosebatho

What is HIV?:

What is HIV? HIV is a Human Immunodeficiency Virus contracted in variety of ways, i.e. blood-to-blood or body fluid contact with an already infected person. The destructive virus mainly affects the T-cells, which are commonly referred to as CD4+ cells. These are the white blood cells that help the immune system kick in and fight the disease. Once inside the CD4+ cells, HIV continues to produce millions of tiny viruses which will kill off the cell before seeking out another one. Eventually the number of CD4+ cells will die off and the immune system won’t be able to fight anymore. It is at this time a person may get the diagnosis of HIV and need anti HIV drugs to keep it under control. Being diagnosed with HIV doesn’t mean a person has AIDS. Without drugs HIV will progress to AIDS within a decade – although that really depends on where you live. People in developing countries where diet and healthcare are poor progress to AIDS far quicker. However, someone with the virus who takes anti HIV medication can have a very good quality of life and it may be many years before the disease develops into AIDS. Nowadays, around five million people a year worldwide contract HIV - and the figure is still climbing. About 95% of these cases are in the developing world, where poverty, poor healthcare and ignorance of prevention measures feed the spread of the disease.

Viral infection:

Viral infection

How is HIV contracted?:

How is HIV contracted? Bearing in mind how destructive it is, HIV is regarded as a fragile virus. It can only survive in moist conditions, which is why it is transmitted through bodily fluids such as blood, semen, vaginal secretion or breast milk. It cannot penetrate through unbroken skin – or condoms for that matter. So many myths have been built up about how you contract HIV. Well, truth is that you can’t contract HIV from hugging or shaking hands, or even a social kiss. Fears of picking up the disease from a swimming pool or toilet are also unfounded. HIV can only be contracted through unprotected sex, sharing dirty needles or via a blood transfusion from an infected person. An HIV positive woman can pass the disease to her children through pregnancy, birth or breast feeding.

Viral transmission:

Viral transmission

How would HIV affect our bodies?:

How would HIV affect our bodies? Changes in the immune system. Billions of CD4+ T cells may be destroyed every day, eventually overwhelming the immune system’s capacity to regenerate. The interplay between the human immunodeficiency virus (HIV) and the immune system turns out to be significantly more dynamic than most scientists would have suspected. Recent research indicates that HIV replicates prodigiously and destroys many cells of the immune system each day. Apoptosis Infected CD4+ T cells may be killed when the regulation of cell function is distorted by HIV proteins, probably leading to cell suicide by a process known as Apoptosis (programmed cell death). Apoptosis occurs to a greater extent in HIV-infected people, both in their bloodstream and lymph nodes. Uninfected cells also may also undergo apoptosis. Investigators have shown in cell cultures that the HIV envelope bound to antibodies sends an inappropriate signal to CD4+ T cells causing them to undergo apoptosis. Direct cell killing Infected CD4+ T cells may be killed directly when large amounts of virus are produced and bud out from the cell surface, disrupting the cell membrane, or when viral proteins and nucleic acids collect inside the cell, interfering with cellular machinery.

How would HIV affect our bodies?:

How would HIV affect our bodies? Innocent bystanders Uninfected cells may die in an innocent bystander scenario: HIV particles may bind to the cell surface, giving them the appearance of an infected cell and marking them for destruction by killer T cells after antibody attaches to the viral particle on the cell. This process is called antibody-dependent cellular cytotoxicity . Killer T cells also may mistakenly destroy uninfected cells that have consumed HIV particles and that display HIV fragments on their surfaces. Alternatively, because HIV envelope proteins bear some resemblance to certain molecules that may appear on CD4+ T cells, the body’s immune responses may mistakenly damage such cells as well. Anergy An inactivated state that turns CD4+ T cells off by activation signals from HIV that leaves them unable to respond to further immune stimulation. Damage to precursor cells Studies suggest that HIV also destroys precursor cells that mature to have special immune functions, as well as the microenvironment of the bone marrow and the thymus needed for developing such cells.

Anergy:

Anergy

How would HIV affect our bodies?:

How would HIV affect our bodies? Changes in body organs 1. CD4-lymphocytes or T-cells. T-cells are responsible for coordinating cell-mediated immunity (CMI) - defending against viruses, bacteria, fungi, and parasites that we are constantly exposed to. Although viruses are part of CMI defences, HIV weakens the part of the immune system that can defend the body from HIV itself. This sets into motion a vicious cycle of lowered immunity, more viral reproduction, which kills T-cells faster and faster in the untreated human despite valiant efforts by the body. When the CD4-count is less than 250 or so, symptoms develop to indicate the state of "full blown" AIDS (acquired immunodeficiency syndrome). 2. Cells of the Nervous System. 1.  Peripheral neuropathy is characterized by numbness and/or pain (burning or pins and needles sensation) that usually begins in the soles of the feet and may rise the legs to involve the entire body. 2.  HIV encephalitis is an inflammatory condition of the brain that over long periods of time results in actual death of brain cells; when this process goes on long enough, the afflicted person may develop short term memory problems, confusion or other more "localized" problems like seizures.  Dementia may be the end result. 3.  Cytomegalovirus (CMV) can infect the eyes ("retinitis") and cause blindness.

Deteriorating GIT effects :

Deteriorating GIT effects

How would HIV affect our bodies?:

How would HIV affect our bodies? 3. Gastrointestinal (GI) tract cells. The GI tract consists of the entire "tube" from the mouth to the anus & is surrounded by lymph tissue which is one of the best reproductive grounds for HIV. Problems with the GI tract include reduced absorption ( malabsorption ) of nutrients and drugs which impairs the immune system further and sets into play another vicious cycle of weight loss and diarrhea . The entire GI tract ( + liver & bile ducts) may be affected by HIV as well as opportunistic infections such as tuberculosis ( mycobacteria ). 4. Other affected organs. Skin – its integrity is compromised and bothersome symptoms like itchy red bumps, deep seated infections – staph abscesses(boils) develop. Bone marrow – as the site for blood cell formation, becomes even more damaged thus giving way for further destruction of blood cells. Low erythrocyte count can predispose to Anaemia, low leukocyte count can predispose to infections & low thrombocyte count can predispose to bleeding. Muscles – physical endurance is highly challenged due to Anaemic symptoms of muscle fatigue & shortness of breath. Genital organs - hormones in the body are affected by HIV infection in some cases, and in particular the male sex hormone (testosterone) is lowered in many men with AIDS so that weight loss becomes depressed.

Skin lesions:

Skin lesions

How would HIV affect our bodies?:

How would HIV affect our bodies? Changes in blood cells. The HIV virus attacks T-helper cells, or CD4+ cells, by fitting itself into the cell like a key in a lock. Once it has invaded, it can use its own RNA as a template to make copies of itself, multiplying and travelling through the body. This process destroys the body's own T cells over time; as the T-cell count falls, the body's resistance to germs and disease also declines. Macrophages and certain other kinds of cells which can engulf substances through phagocytosis . As a consequence of the interaction with CD4 on helper T-cells, HIV specifically infects the very cells necessary to activate both B-cell and cytotoxic T-cell immune responses. Without helper T-cells, the body cannot make antibodies properly, nor can infected cells containing HIV (an intracellular pathogen) be properly eliminated. Consequently, the virus can: multiply, kill the helper T-cell in which it lives, infect adjacent helper T-cells, repeat the cycle, and on and on, until eventually there is a substantial loss of helper T-cells.

How would HIV affect our bodies?:

How would HIV affect our bodies? Symptoms of HIV Physical Rash Fatigue Dry mouth & throat Swollen lymph nodes Extreme weight loss Protruded eyes Fever Night sweats Peripheral neuropathy Psychological Depression Suicidal thoughts & attempts Memory loss

Who is vulnerable to HIV?:

Who is vulnerable to HIV? Back in the early 1980s, before blood was screened for HIV, the infection was transmitted through contaminated blood during transfusions. In the late 80s a large number of people started displaying the symptoms of HIV after receiving blood several years before. Hemophiliacs in particular were affected. But the risk of getting HIV from infected blood these days is miniscule. Blood screening and specialist heat treatment work together to ensure that no such blood gets used in transfusions. An HIV positive pregnant woman can pass on the virus to her child before or during birth because of the sharing of blood. She can also pass it on through her breast milk. That being said, it’s indeed a travesty for any child to be born with an already set, death sentence. Children are undoubtedly the most vulnerable victims in this epidemic.

Can HIV be treated & managed?:

Can HIV be treated & managed? Medication Integrase Inhibitors - Integrase is an enzyme that does what the name implies; it integrates HIV genetic material into the DNA of human CD4 cells making it possible for the infected cell to make new copies of HIV. By interfering with integrase during the HIV life cycle, the integrase inhibitors prevent HIV genetic material from integrating into the CD4 cell, thus stopping viral replication. Entry Inhibitors Entry Inhibitors work by interfering with HIV's entry into the CD4 cell. By interfering during the entry phase of the HIV life cycle, thus, entry inhibitors block HIV replication. Non-Nucleosides Reverse Transcriptase Inhibitors (NNRTI's) NNRTIs work by binding tightly to the enzyme reverse transcriptase which prevents viral RNA from converting to the viral DNA that infects healthy cells. Protease Inhibitors (PI's) PIs stop HIV replication by preventing the enzyme protease from cutting the virus into the shorter pieces that it needs to make copies of itself. Thus, forming incomplete, defective copies are formed which can't infect cells. Nucleoside Reverse Transcriptase Inhibitors (NRTI's) NRTIs work by being incorporated into the viral DNA, making it ineffective. These compounds suppress replication of retroviruses by interfering with the reverse transcriptase enzyme. The nucleoside analogs cause premature termination of the proviral (viral precursor) DNA chain. Combination Medications In an effort to improve medication adherence and to make it easier to take your medications each day, many medications are combined into one pill or capsule. Fewer pills each day has been shown to improve adherence which we know improves the effectiveness of HIV regimens.

Can HIV be treated & managed?:

Can HIV be treated & managed? Side effects Nausea Diarrhea Vomiting Weight loss Cure Currently there is NO cure for HIV and AIDS, so once someone becomes infected, they’re infected for life. Experts believe that people with AIDS eventually will die from it, unless death from another HIV/AIDS related cause occurs sooner. hepatitis is an inflammation of the liver. Hepatitis can be caused by viruses, bacteria, and a number of other non-infectious medical conditions. syphilis is a sexually transmitted disease that, if untreated, can lead to serious lifelong problems throughout the body, including blindness and paralysis. tuberculosis is a bacterial infection that primarily attacks the lungs but can spread to other parts of the body. Prevention Always practice safe sex (condomise during all types of sex). Avoid multiple sexual partners (remain faithful to only one partner). Ensure extra precautions in the case of any blood transfusions. Avoid IV drug use & never share needles for drugs, steroids, medications, tattooing, or body piercing. NB – Know your status (Save lives & prevent re-infection).

What type of research has been done thus far on HIV?:

What type of research has been done thus far on HIV? Cause of HIV This virus has been under intense scrutiny for several years, now (since approximately 1985), and an astonishing amount of information has been gathered. One must wonder, "why isn't there a cure?" There isn't a cure primarily because there isn't a cure for most viruses. We do not yet know how to specifically kill a virus which spends most of the time hiding inside of our cells. The substances which we know of that can directly harm such a virus, unfortunately can also harm our own cells. Unlike our immune system, we do not yet know how to direct an attack on only those cells which are infected with the virus. Our knowledge so far allows us only to attack all of our cells (much like we do in chemotherapy for cancer treatments). We can't even sort-of focus an attack, as one can do with radiation treatment - if radiation treatment were used for HIV infections, this treatment would significantly hurt our immune system's ability to function, which is the opposite of the main objective.

HIV progression in a nut-shell:

HIV progression in a nut-shell

What type of research has been done thus far on HIV?:

What type of research has been done thus far on HIV? Possible cure for HIV So far there has been no success in the development of a cure. In South Africa alone, AIDS has killed more than 350,000 people and has become the principal cause of death among those 24 to 44 years old. Another 750,000 people harbour the HIV virus, part of some 30 million who are affected worldwide. Thus, we have vaccines against poliovirus, smallpox virus, measles virus, influenza viruses, etc. The vaccine per se does not fight the virus, but instead causes an immune response specifically directed against the particular virus. This response directly increases the number of specific B- and T-cells available to respond against a live virus infection encountered at some later time. At this point in time Gene therapy seems to be the only promising possibility in eradicating HIV. Though still in its trials , this methodology aims to alter human genomes to fix potentially deadly mutations. The down-side however, is the difficulty in delivering therapeutic agents (DNA) to host genome, the lack of efficiency in current methods of genetic insertion & HIV mutations due to continuous HIV re-infections in victims. Results, though promising, are short & limited due to genome copies (act as barriers) which block plasmid movement & the expression of new DNA. With proper regulation & control, gene therapy methodology may become the solution in fighting any form of disease

Gene Therapy methodology:

Gene Therapy methodology Gene Therapy Using Plasmid DNA Disguising Plasmids in Lipids and Polymers to Enhance Nuclear Localization Viral Vectors as a Method for Delivering Therapeutic Agents

Conclusion:

Conclusion In the past few years, advances in drug therapy have enabled a number of patients to cheat death. Sophisticated combinations of medicines have diminished the levels of virus in the body and restored immune function. To date, the most effective treatment against viruses is to develop a vaccine - which stimulates our own immune system to enable our immune system to better fight the virus. To date, HIV/AIDS statistics worldwide have escalated way beyond medical advancements. It’s time we went back to the drawing board & re-introduced ourselves to this HIV virus. Where does HIV virus originate from? – Have concrete understanding of an organisms development – GENETICS! What is it compatible with ?– VACCINE! We must re-evaluate the factors contributing to the high infectious HIV rate & start at ground level in trying to understand & handle such challenges. HIV/AIDS does not discriminate. It can infect & affect anyone irrespective of gender, age, race, nationality or even sexual orientation. *Education is key, in preventing HIV*

References:

References www.hivinfo.us/hivgeneral.html www.fda.gov/oashi/aids/virals.html http://people.ku.edu/~jbrown/hiv.html http://www.wikipedia.en_wiki.metabolism.com Sherwood L. 2007. Human Physiology – from cells to systems. 6 th edition. Thomson, Brooks/ Cole:Belmont .