Introduction
Human Immunodeficiency Virus (HIV) attacks the immune system and makes it weak against infections, it belongs to the retrovirus class under a subgroup called lentiviruses. Almost every HIV-infected person will eventually develop and die from AIDS if the virus is untreated. The World Health Organization reports show more than 50 ...
Introduction
Human Immunodeficiency Virus (HIV) attacks the immune system and makes it weak against infections, it belongs to the retrovirus class under a subgroup called lentiviruses. Almost every HIV-infected person will eventually develop and die from AIDS if the virus is untreated. The World Health Organization reports show more than 50 million cases have been reported and 30 million of them died of AIDS as a direct result of a pandemic since the outset. Africa and the U.S show most cases worldwide.
Structure of HIV
HIV is an enveloped virus 100 nm in diameter, composed of two strands of RNA for its genome. The outer layer of the envelope contains proteins that help the virus invade the next host. The most important proteins are gp120, which helps in attaching to the CD4 receptor, and gp41, which is responsible for the virus’s fusion with the cell membrane and entering inside the cell. The envelope contains a viral matrix and p17 helps in holding onto gp120 and gp41. Inside the matrix is the viral core, made up of p24. The viral genome, as well as the enzymes required for virus replication in the host cell, are stored in the core.
Life Cycle of HIV
Understanding the HIV life cycle has aided in the development of medications to treat the disease. It enables us to figure out how the virus replicates itself, allowing us to create strategies to prevent that process. From the attachment of the virus to the host cell until the sprouting of new free-circulating HIV virions, the HIV goes under various phases to complete its life cycle.
- Binding and fusion: The virus attaches to a T-helper cell after that fuses to it and releases its genetic information into the cell. The several types of drugs that inhibit this phase of the lifecycle are called fusion or entry inhibitor drugs – because they stop HIV from merging into the cell.
- Reverse Transcription: Before HIV RNA can be incorporated into the DNA of a CD4 cell, it must first be converted to DNA. This fusion is required for the virus to proliferate. Reverse transcription is the process of converting HIV RNA to DNA, which is mediated by the HIV enzyme reverse transcriptase. As a result, a single strand of DNA is produced from viral RNA. After that, the single strand of this new DNA is replicated into double-stranded HIV DNA.
- Integration: After reverse transcription, viral DNA can enter the nucleus of the CD4 cell. The viral enzyme integrase then inserts the viral DNA into the DNA of the CD4 cell. This is referred to as integration. The CD4 cell has now been transformed into a factory to produce more HIV.
- Replication: The new DNA, which is formed as a result of the viral DNA integration into the CD4 cell, stimulates the formation of mRNA, which synthesis HIV proteins.
- Budding: All the components required to create a new virus, including HIV proteins and viral RNA, congregate at the CD4 cell membrane to form new viruses. By budding, these new viruses pass through the different parts of the cell wall. Many viruses can pass through the membrane of a single CD4 . These new viruses emerge from the CD4 cell with all of the required components to infect other CD4 .
- Maturation: The new virus contains all of the components required to infect other CD4 cells, but it cannot do so until it matures. Throughout this process, the HIV protease enzyme breaks down the virus’s long HIV proteins into amino acids functional units, which are then reassembled to form a mature virus infect other cells.
Effects on the Immune System
HIV pathogenesis is essentially a battle between HIV replication and the patient’s immunological responses, both cell-mediated and immune-mediated. CD4 T-cell destruction is mediated by HIV viral load, both directly and indirectly. CD4 progenitor cells in bone marrow, the thymus, and peripheral lymphoid organs, as well as CD4 cells inside the neurological system, such as microglia, are all destroyed. T-cell generation fails as a result of this damage, leading to immunological suppression. There are numerous mechanisms by which HIV infection depletes CD4 cells. Single-cell killing as well as cell fusion, or syncytium formation, are examples of direct HIV-mediated cytopathic effects. The syncytium is formed by the interaction of multiple uninfected CD4 cells with one HIV-infected CD4 cell via the CD4–gp120 receptor. This fusion produces a multinucleated syncytium, or giant cell, which may eventually be used to produce a large number of virions. Natural immune responses of the host also contribute to CD4 cell depletion, primarily through cytotoxic CD8 T-cells, antibody-dependent cellular cytotoxicity, and natural killer cells. Other mechanisms include autoimmune reactions, energy, superantigen-mediated T cell activation, and programmed cell death (apoptosis).
The virus can infect a wide variety of cells. HIV usually spreads outside of lymphoid organs to the lung, nervous system, colon, liver, and kidney late in the illness.
Transmission of HIV : It is essential to comprehend the main modes of HIV transmission. HIV is mainly transmitted via blood and other body fluids, such as semen, vaginal secretions, and breast milk. Unprotected sex with an HIV-positive person, and also direct contact with HIV-infected blood via shared syringes and needles, open wounds, or mucous membranes (eyes, mouth, rectum, vagina), may result in transmission. HIV infection seems to be extremely unlikely to occur simply through brief contact among infectious bodily secretions and intact skin. The risk of HIV infection from a single sexual act is typically low, but receptive anal sex is the most dangerous, followed by receptive vaginal sex. HIV cannot be transmitted across saliva, sweat, or tears, so oral sex is a negligible risk.
Signs and symptoms of HIV
As the virus spreads and damages immune cells, the body’s cells aid in the battle against pathogens.
- Mild infectious diseases or chronic symptoms may develop in the patient, such as:
- Loss of weight
- diarrhea-Fatigue
- yeast in the mouth (thrush)
- roof shingles (herpes zoster)
- Lymph nodes swollen
- Pneumonia
- fever
- progression to AIDS:
If HIV is not treated, the majority of people will develop AIDS. When a person has AIDS, their immune system is severely harmed, leading to the development of opportunistic infections, opportunistic malignancies.
The following are the signs and symptoms:
- Sweats
- a weight loss
- weakness
- diarrhea
- Fever
- Chills
- Lymph glands swollen
- White patches
Complications of AIDS:–Pneumocystis pneumonia (PCP): This fungal infection can cause serious illness of pneumonia in people infected with HIV.-Candidiasis (thrush): Candidiasis is a common HIV-related infection. It causes inflammation and gives a thick white coating to the mouth, tongue, or vagina.-Tuberculosis (TB): In countries with limited resources, tuberculosis is the most common opportunistic infection associated with HIV. It is the leading cause of death for AIDS patients.-Cytomegalovirus: The herpes simplex virus is spread by body fluids. The virus is inactivated in a healthy immune system and remains latent in the body. The virus resurfaces if the immune system weakens, causing harm to organs.-Meningitis: is caused by bacteria, meningitis is a condition in which the membranes and fluid that surround your nervous system are inflamed (meninges). -Toxoplasmosis: caused by Toxoplasma Gondii parasite, when toxoplasmosis spreads to the brain, it can cause heart problems as well as seizures.-Lymphoma is cancer that is commonly associated with HIVAIDS. White blood cells are the origin of this malignancy. Painless swelling of the lymph nodes in your neck, armpit, or groin is the most frequent early indication.-Kaposi’s sarcoma: is a malignancy of the blood vessel walls that causes pink, red, or purple sores on the skin and mouth.
Laboratory methods to diagnose HIV and AIDS
- Elisa
- Western blot
- PCR
- p24 antigen
- Qualitative PCR, Quantitative RNA PCR, and genotyping
Treatment and Prevention
There’s no vaccine to prevent HIV infection and no cure for AIDS. But you can protect yourself and others from infection.
To help prevent the spread of HIV:
- Use treatment as prevention (TasP). If the patient contracted HIV, taking HIV medication can keep the partner from becoming infected with the virus. If the patient makes sure the viral load stays undetectable.
- when it’s needed use a clean needle.
- inform the spouse if the patient tested positive for HIV.
- Consider male circumcision.
- If the patient is pregnant, get supervised professional treatment right away.
Consider preexposure prophylaxis (PrEP). The mixture of tablets emtricitabine plus tenofovir (Truvada) and emtricitabine plus tenofovir alafenamide (Descovy) can lessen the chance of sexually transmitted HIV in human beings a lot. PrEP can lessen the chance of having HIV from intercourse by a 90% and from injection drug use by a 70%, according to the Centres for Disease Control and Prevention, but it hasn’t been studied in a human who has had receptive vaginal intercourse. the health practitioner will prescribe the tablets for HIV prevention in case the patient doesn’t have HIV. It is advised to check for HIV before taking PrEP and periodically get tested every 3 months.
References
- https:acphd.orghivhiv-aids-basics
- https:www.avert.orgprofessionalshiv-scienceoverview
- https:www.aids.gov.hkpdfg190htm01.htm
- https:www.avert.orgabout-hiv-aidshow-infects-body
- https:bipai.orgsitesbipaifiles2-Pathophysiology-of-HIV.pdf
- https:www.mayoclinic.orgdiseases-conditionshiv-aidssymptoms-causessyc-20373524
