Introduction on HIV/AIDS

INTRODUCTION

Infection with human immunodeficiency virus (HIV) and the Acquired immunodeficiency syndrome (AIDS) are urgent problems worldwide with broad ,social, cultural, economic, political, ethical and legal implications. Most people already have some idea of what AIDS is . they know it is spread sexually – although they many not have a clear idea of what “sexually” means; they know it often fatal. In some countries, as a result of coverage in the media, people believe it is only a problem of certain “high – risk “ groups. Some people believe (wrongly) that it can be transmitted by handshaking or by sharing cups. A lot of people are very frightened.

Acquired Immuno-Deficiency Syndrome – AIDS) – is a word that was barely known about fifteen years ago in Nigeria and Africa. Today, several thousand of people worldwide have developed the deadly condition denoted by these four letters, A-I-D-S. And the global epidemic continues to rise, HIV, the virus that cause AIDS is a very small germ which cannot be seen with the naked eyes. It affects the body’s immune (protective) system, thereby making the body weak and less able to fight off disease and infections. If HIV enters one’s blood stream, the person may be infected. From the time a person is infected, he or she can infect others, even if no symptoms are present. A special blood test can detect HIV infection. People infected with HIV can develop many health problems. These can include extreme weight loss, severe pneumonia, severe diarrhoea lasting for more than one month, prolonged fever lasting for more than one month and tuberculosis.

Furthermore, a person will not develop AIDS unless he or she has been infected with HIV virus. AIDS is the result of a long process that beings with HIV infection.

A lot of people who have been infected with HIV go on to develop AIDS. The diagnosis of AIDS given when certain unusual opportunistic infections and tumours develop, and certain

aniti-bodies to HIV are found in the blood, Opportunistic infections are infections caused by organisms that are normally present in the body, but to which the body is normally immune. HIV stops the immunity of the body to these particular diseases, thought the body remain unimune to other illnesses. Each of these illnesses can cause the death of the patient, unless they are treated. As HIV multiplies in the body, and takes away the power of the body to combat the infections (as it invades more T4 cells), treatment becomes more and more difficult. While treatment can prolong the lives of many patients with opportunistic illnesses, presently available evidence suggests that most eventually die of one them. The most common opportunistic infections or illnesses are:

· A type of pneumonia called pneumocystis carini pneumonia.

· A variety of gastro – intestinal infections resulting in diarrhoea and weight loos, causing AIDS to be known as “slim” disease in some areas;

· A skin caner called kaposi’s sarcoma ;

· Disorders of the nervous system, sometimes resulting in dementia (deterioration in intellectual capacity), cause by other infections or by HIV itself.

As mentioned earlier, HIV may also trigger the activity of other infections disease which may be carried by individuals, such as tuberculosis, or aggravate the damage done by others.

The presence of kaposi’s sarcoma or cryptococal meningitis are often strong indicator for the diagnosis of AIDS, but these illnesses requires diagnosis by specially trained doctor.

Because laboratory facilities in many countries are insufficient to allow reliable diagnosis of the opportunistic infection and malignant disorders required to define AIDS, and testing for the presence of antibodies to HIV may not be feasible attempt have been made to provide a clinical case definitions. This is most useful in areas where there is a high prevalence of AIDS, but is obviously less useful where AIDS is rare-since so many other diseases, (notably tuberculosis) can present the same symptoms.

The case definition currently used (in those cuistances where proper diagnosis of disease is impossible, and no antibody test is available) consists of the existence of two major signs, in the association with at least one minor sign, in the absence of other known causes of suppression of the immune system- such as cancer or malnutrition. The signs used in the definition are given as:-

MAJOR SIGNS

· Weight loss greater than 10% body weight

· Fever for longer than one month

· Cluronic diarrhoea for longer one month (intermittent or constant)

· Persistent severer fatigue

MINOR SIGNS

· Persistent cough for longer than one month

· General itchy dermatitis (skin irritation)

· Or pharyngeal candidiasis (fungus infections in the mouth/throat)

· Chronic progressive and disseminated herpes simplex infection

· General lymphadenopalthy (swelling of the lymph glands)

At present, it is not clear what proportion of people infected with HIV will go on to develop AIDS. Statistics from different studies vary considerably. In the first five years following infection they report that between 6-45 percent of those infected will go on to develop AIDS (those who have eliminated) several areas of bias tend to fall nearer the lower figure and a further 25-100 percent will develop AIDS – Related complex (ARC) or Generalised lymhadenopathy related to AIDS. Unfortunately, follow-up of patients has mostly being limited to the last five years. As time goes on, and those infected with HIV are followed for longer than five years, more of them do go on to develop AIDS.

A reasonable estimate is that as each year goes by about 12 percent of those initially infected will develop ARC or lymphadenopathy, and 2-9 percent will develop AIDS. Thus some people (if some current figures are correct) may live for 50 years after infection with HIV before they go on to get AIDS. It is thought likely that the illness is continually progressive; to that eventually all those infected will develop AIDS. But it is too early to say whether or not this is true.

The best estimate for the mean incubation period of the virus is about 8 years. This differs according to age. For children up to the 4 years, the mean is 1.97 years, for people aged 5-59 the mean is 8-23 years, and for those aged 60-or more it is 5.5 years.

Once infected, it is likely that a person carries the virus for life, and therefore can transmit the virus. The antibodies that are made in response to the infection do not seem to be protective to the body, although it has been shown that white cells can kill the virus when grown outside the body in laboratonie.

However, there is much more research to done in this area, especially since individuals way so much in their response to HIV, terms of the length of time to acquire antibodies, and the time taken to develop symptoms, or AIDS. Another interesting problem in relation to immunity in the fact that some individuals, even after repeated sexual contact with HIV – infected people, have not been shown to be infected with the virus. On the other hand there are cases when infection had occurred after only one sexual contact.

HOW HIV WORKS AND HOW IT CAN BE DETECTED

The human body responds to infection and disease through the action of cells in the blood called white blood cells. These cells recognise invaders and produce antibodies, which are chemicals that attack and neutralise the invaders.

A specific antibody is produced for each disease, with most disease, once a person has developed antibodies against it, the cells responsible remember how to produce that antibody-and the person is immune to that disease for the rest of their lives.

The antibodies which the body produces in response to HIV, and which can be detected in the blood of an HIV carrier, do not seem to be effective in preventing the spread of the virus in most people.

HJIV attacks and inactivates a particular kind of white blood cell, known as a T4 helper cell. T4 helper cells are vital in controlling the body’s defence to many diseases. They also recognise disease to many diseases. They also recognise disease organisms and cancer cells which the white blood cells must destroy after an infection. The T4 helper cells stimulate the production of a large army of white blood cells to fight the infection. Sometimes they are successful in this. Sometimes the infection or cancer is so over whelming, or grows so rapidly, or is composed of cells immune to the T4 cells, that the illness wins. Sometimes, the body itself suffers from a weakness of the cells that provide immunity, such as the T4 cells, and do the disease overwhelms the body. This partly explains why people can die of any illness.

In ability to the T4 cells to counter some of the many disease to which the body is immune.

However, the body remain able to counter many other diseases and cancers. This is why it is possible to go an living for so long even if a person has AIDS. The few diseases that do occur in such people can be treated. As more and more T4 cells are destroyed, the efficacy of this treatment is reduced, and so treatment becomes harder to maintain.