The body has a two –part Immune system which workers together to protect it from harmful micro organism such as bacteria, fungi, viruses and parasites, it is divided in to two:
This is the front-line defense which equips us from before birth to deal with the various microorganisms that we are likely to meet in our normal everyday lives
Innate Immunity Include:
Antibodies formed by a mother and passed on to the developing fetus and through infant breasting feeding
Tears containing the enzyme lysosome, to protect one eye from bacteria
Saliva in the mouth, also containing the anti-bacterial lysosome
Mucus and chemicals co-existing but with quite differing functions in the urethra Ureter (water tubes) and vagina
When the barriers of the innate immunity are penetrated ,while blood cells leukocyte.(phagocytes or devouring cells) and other while cells (principally serotoxin or natural cell-Killing cells)surround and a number of other naturally-produced substances such as interfere and a range of blood proteins (called the complement system combine to help in the destruction process.
Adaptive Immunity is the second line of defense and is called into service when the defenses of the innate immunity are breached well beyond the capability of its response, Its defense, instead of being a general reaction is much more specific as it adapts to the particular organism present hence adaptive immunity is often referred to as specific immune system to identify the invading micro-organism as being foreign to any of the body’s own protein these foreign or devouring cells) and other while cells (principally serotoxin or natural cell-killing cells) surround and attempt to destroy the invader. At the same time a number of other naturally-produced substances such as interferon and a range of blood proteins called the complement system) combine to help in the destruction process.
Adaptive Immunity is the second line of defense and is called into service when the defenses of the innate immunity are breached well beyond the capability of it response. It defence, instead of being a general reaction is much more specific as it adapts to the particular organism present hence adaptive immunity is often referred to as specific immunity.
Body immunity is the ability of the body o define itself against foreign bodies ( antigens) its commonly associated with the blood cells which comprise the soldier cells of the body.
Body immunity system it’s important because it equips as our bodies with the ability to control act foreign invaders.
We have two types of immunity
Innate immunity- natural ability of the body to defend itself against micro –organism and it’s always transmitted from parent to children. Example of innate immunity
- Lysosome –protect eyes and mouth from being infected by bacteria.
- hairs-in nose help trap inhaled
- mucus has cilia hairs found in trachea and wind pipe when by they protect the lungs by ensuring that foreign matters don’t affect.
- Skin – its layer protect the body surface, serviced by (sweat glands) sebaceous gland providing bacterial killing chemical s.
- acids – in stomach and intestine (HCl) which destroy harmful microorganism and also permit the present of helpful bacteria.
This is artificially induced attenuation ( inoculation) this is type of immunity called intro service when the inmate immunity is destroyed beyond response .
There are around 7 days between immune response as one part of the system takes over from the either.
The response can either be cellular or hormonal based on the type of invader.
Hormonal immunity response to bacteria while cellular responds to virus and parasite.
Effects of HIV/ aids on the body immunity
- Weaken the body immunity leading to opportunistic infection.
- Inhibit the production of CD4 cells.
- Destroy immune system.
T- Killer cells termed as cytolysis t- lymphocytes.
Upon entry in the body HIV moves n migrates to the lymph nodes in different parts of the body e.g. neck, groins and armpits.
The lymphatic system which include the lymph nodes act as a reservoir for the virus it then moves other parts of the body where it infect and destroy white blood cells (t- lymphocyte or CD4 cells)
The lymph nodes normally trap bacteria , fungi and virus to allow easier destruction by the WBC they are contracted by there but as the virus concentration increases there s both breakdown in the ability of the lymphocyte to hold back.
Infection and the destruction of the CD4 cells
The breakdown of the lymph nodes barrier allow rapid spread of the virus into the blood stream and other parts of the body.
According to the diamond HIV / aids research centre (US) says that infected die on average every two days and that unto 100 billion new viruses are released daily. When the virus enter CD4 cell, it takes unto 30 hrs to cope with genetic material produce new enzyme and other viral component then they are assembled into new viruses.
Steps in viral replication
The HIV virus first defined in the US in 1983 is classified in the family of tentrovidae within genus retrovirus. Retrovirus has RNA genome which also poses a unique transcriptase (reverse transcriptase)
HIV virus itself to human cell so as to inject its genetic materials into the cell on the surface of the cell through molecules called receptors
Using receptors the HIV cells attaches itself and fuses into the cell membrane. a process called fusion to do this HIV uses GP120 to attach itself to human cell and GP 41 to fuse into the human cell.
After fusion with the cell, the virus transfers its instruction which reprogram the cell to produce copies of the cell. This instruction is known as RNA are similar to DNA contained by all cells of the body. An enzyme reversed transcriptase convert the single stranded HIV RNA to double stranded HIV DNA. A class of drugs known as transcriptase inhibitors
Once HIV has converted itself to HIV DNA moves towards the host cell nucleus which is the command center of the cell It does so through the use of enzyme called intergraded inside the cell nucleus. HIV hides its DNA in the host cell DNA when does two things i.e.
- Stays in the cell
- Once activated uses the host cell DNA to make more copies of it.
Intergraded inhibitors are drugs used to inhibit the interrogation process.
The cell nucleus when activated commands the cell to reproduce HIV. The building block for the new HIV viruses reproduced in form of chain using an enzyme called process act as scissor, the long chain is cut into pieces and this process is called cleavage.
This cut pieces packed together by the help of the protease enzyme to form new virus protease inhibitors are drugs used to inhibit the process.
After packaging HIV moves to the outer part of the cell to escape process called budding.
HIV uses the part of the cell outer membrane to complete its final structure. The new HIV particles leave the cell in search of new cell to infect and start the process again.
Clinical stage in HIV
Modes and non modes of transmission of sexually transmitted disease and infection
HIV transmission is the spread of HIV virus from one person to another by different routes. HIV is spread when an infected individual comes into contact with infected body fluids or cells. The virus is found in blood, breast milk, semen and virginal secretion. In high concentration and saliva in low conclusion
HIV can be transmitted through various modes sexual contact – the commonest mode, any unprotected penetration sex whether virginal , anal or oral can transmit the virus from an infected individual to uninfected .
Sexual contact accounts for 70-80 percent transmission. Homosexual accounts for 10-15% HIV infection by sexually account for between 1-3%.
Oral sex is associated with a lower risk but gonorrhea and genital cancer and syphilis do but the risk of transmission.
Deep kissing weak ‘oral saliva is exchanged causes some risk of HIV transmission especially when one or both partners have bleeding gums , shivering of tooth brush and toothpicks have small risk.
Factors influencing the risk of HIV transmission
- No of sexual partners. The higher the number off sexual partners one has the higher the chances of contracting HIV.
- The level of virus in the body fluid. The higher level of risk in body fluid (blood, semen, virginal secretion) the higher the risk of transmission.
- Sexual orientation. Being homosexual , homo sexual or unprotected sex influence a great deal of HIV transmission , unprotected guys sex causes great
- the chances of a woman contracting the virus from an infected man is statistically higher than the chances of uninfected man can contract the virus s from an infected woman.
- Younger women are at higher risk as opposed to other women this is because during sexual intercourse virginal tissue tears and get fractured because they are not fully developed.
- Sexually transmitted disease. Presence of STDS increases chances of HIV infection because they cause ulcer and lesions that open up the skin.
- Mother to child transmission disease. World wide rate of HIV infection from mother to their children ran from 13-40% i.e. 4% out of 10% children born to HIV positive e mothers contract HIV.
Ways of mother to child transmission
- The child can be infected before birth by virus crossing from the mother blood to the child through placenta. About 35% of newly born infant which are HIV infected at birth.
- The child can contract HIV through exposure to mother blood and other expulsion during birth. This account for about 05% of newly born HIV infected at birth is most of mother to child transmission occur during birth.
- The child can contract HIV positive mother that get infected with HIV contract virus as a result of breast feeding.
The following factors increase the chances of MTCT.
- High level of HIV in mother blood and other body fluid and secretions.
- Premature babies more prone to infection
- Low birth weight
- Prolonged membrane rapture
- Traditional birth delivery.
- Blood transfusion. Use o blood products that have not been screened for HIV or have been poorly screened can lead to HIV transmission. It constitutes 3-5 % of all HIV infection.
- Intravenous drug use / contact with contaminated instruments. its the administering of drugs of addiction e.g. heroine into blood stream by injecting into veins most of the group members often shave with some needless of their r chances of infection , account 5-10% HIV infection. procedures such as ear piercing , circumcision when done with poorly cleaned and unspecialized instrument can lead to transmission for previous person used on was HIV positive. Rape/ occupational exposure. Exposure to HIV can also be as a result of rape or occupational exposure to healthcare providers such as doctors and nurses. Occupational exposure is the accidental exposure of healthcare worker to body fluid form a positive infected person in their care. Can be due to needle pricks or cut with surgical instruments.
Rape an sodomy victim could also get infected with HIV if the attacker is HIV thus its important that the victim seek prompt medical attention as early treatment with ARVS could reduce chances of HIV infections.
The HIV epidemic in sub Saharan Africa has had a far more damaging societal impact not only because of extremely high number of people infected but also heterosexual transmission.
Way HIV is not transmitted
- Mosquito bites
- Sharing utensils
- Living with infected person
- Touching an infected person
- Having your hair cut
- Sharing drinks
- Wearing second hand clothes
- Sitting next to an infected person
- Using the same toilet with infected person
- Coughing and sneezing
General trend of HIV
- HIV is spreading very rapidly globally
- No of orphans and vulnerable children are increasing more and more women and children are being infected.
- More and more women and children are being infected
- Between 4-5 girls and young women are infected with HIV for every one young man infected.
- People who are living in poverty are more vulnerable to HIV infections.
- Aids has no cure
- HIV is preventive