Few of us give much thought or spare many minutes on what is happening in the perennial struggle between humanity and its invisible deadly foe, the ultramicroscopic particles of the parasitic pathogenic micro organism that we know by the acronym HIV.
Sometime in the last years of the last century a virus then unknown to the medical world made a species jump from its natural animal host in the tropical forests of West Africa and give origin to a new plague affecting man. The virus probably lived quite happily in its primeval jungle but it came upon a new fresh and fertile pasture in a virgin population among mankind.
Zoologists report that chimpanzees have an AIDS-like infection (Simian Aids) caused by a virus very much like HIV.
HIV has now got a very firm foothold on mankind using three main routes of invasion: (a) the universal sexual acts, natural or perverse, homosexual or heterosexual; (b) the injection directly into the body of the victim, either by medical therapeutic procedures of blood and blood products or by the use of communal contaminated needles by addictive drugs victims and (c) the transfer of the virus from a mother to her offsprings before or during birth and after through the maternal milk.
It is estimated that there might be 42 million infected persons at this time and three million will die in a year.
It is thought that the beginning of the awareness of the present pandemic was in the US (1981) when four young homosexuals were hospitalised suffering from prolonged bouts of fever and multiple infection which included a rare type of pneumonia caused by a fungus (Pneumocystis carinii) and one patient developed also an unusual type of tumour for his age group (Kaposi sarcoma).
Readers will remember those liberal heady days when the young folks practised free love and shouted Flower Power and homosexuals flocked to California and gay people came forth in the open and were not shy to be counted; at that time the new clinical condition was called "gay related immune deficiency".
Once the HIV has gained entrance into a human body, like the proverbial Trojan horse it plays havoc with the normal human protective defensive system namely the immunology mechanism with which humanity has been endowed over the thousands of years of our evolutionary history and whose function it is to act as a watchdog, to neutralise and to eliminate any noxious foreign matter which may constitute a danger to the well-being of the body and would otherwise cause disease and ultimately demise in those affected. Early in the 1980s there was quite a hullabaloo as who was in fact the first to discover the new virus.
Luc Montagnier (France) and Robert Gallo (US) claimed priority and named it LAV and HTLV-3 respectively. The International Committee for the Taxonomy of Virus decided on the simple designation of HIV (Human ImmunoDeficiency Virus) and the disease AIDS (Acquired Immunodeficiency Syndrome).
A - acquired, because it is not inherited;
B - immunodeficiency, because it results in a defective immunity system;
C - syndrome, because it causes quite a number of medical conditions.
En passant, having isolated the virus and developed laboratory diagnostic tests for this infection, tests done on some old stored material suggest that this disease may have occurred many years before the 1980s without attracting world wide attention.
In the world of virology HIV is classified as a Retrovirus.
Viruses are the simplest and most elementary creatures. They consist of just a speck of nucleic acid (their genome), which is protected by a protein coat. They must live inside body cells and make use of the host cell machinery to survive and replicate.
Viruses may be broadly classified:
A - DNA viruses containing deoxyribonucleic acid;
B - RNA viruses containing Ribonucleic acid;
C - Retroviruses also containing RNA. But in this important class the RNA produces DNA ,which incorporates itself with the host cell nucleus. This unusual process is made possible by means of an enzyme Reverse Transcriptase. Hence this class of viruses are called Retroviruses, and are treated by anti-retroviral drugs.
HIV-AIDS is now public enemy no. 1. The course of the disease runs in three phases.
The first phase is the acute phase starting about 15 days after exposure to infection. The patient complains of fever, malaise, sore throat, mouth ulcers, diarrhoea, night sweats, enlarged glands. This is followed by months or years of relative freedom from symptoms but the enlarged glands persist.
In this second phase the impaired immunity defence system becomes very evident. Patient complains of fever, diarrhoea, rashes, herpes zoster, thrush etc. and the lymphglands are enlarged.
Finally comes the full picture of AIDS. The patient is now wide open to all sorts of opportunistic parasitic organisms, viruses, bacteria, fungi and also liable to cancers (cervical cancers, Kaposi's sarcoma).
The present pandemic of HIV-AIDS is very much in the minds of very worried governments and international organisations. Likewise the drug manufacturers must be working night and day to produce anti-retroviral drugs.
The virus replicates at a tremendous rate, possibly up to billions of viruses in a day, and so it has good chances to mutate and if only one drug is used it soon becomes evident that the patient is not responding to treatment. So single drug administration is not recommended and two or more drugs have to be used. This management is sometimes called HAART, that is highly active antiretroviral therapy.
The drugs used are cleverly designed to attack the HIV in the various stages of its life cycle: its entrance into its favourite target host cell (CD4 T Lymphocyte also known as Helper T cell) or to prevent its replicative process once intracellular or to interfere with its escape from the host cell as a virulent complete HIV.
Efforts are being made (note the activities of former US President Jimmy Carter) to persuade the drug firms to reduce the price of their products as many of the countries which are worst hit in this pandemic are too poor and cannot afford the prices to treat all their suffering citizens.
Remember AIDS, as described above, behaves quite different from other diseases that plague humanity such as Typhoid or Streptococcal Tonsillitis where the patient is given a course of an appropriate antibiotic, is cured and that is the end of the story. The drug treatment in AIDS can suppress the signs and symptoms but it is very difficult, if at all possible, to eliminate completely the virus. They have been found useful to be given to pregnant women in order to protect their unborn babies.
Early in the 1980s when HIV-AIDS first hit the headlines as a fearful new pandemic, laboratory diagnostic tests were devised and made available. Thus counts of the affected target cell (CD4 ) give an indication of the severity and progress of the infection. Laboratory tests can also detect the viral load in the blood stream (PCN test - polymerase chain reaction). Specific HIV antibodies in the patient's serum can be detected by enzyme tests (ELIZA) and by electrophoresis (Western Blot). The virus itself can be isolated and cultured as we have seen above. These tests can help in the diagnosis and also in the management of the patient whose life is now prolonged by modern therapy.
The reader will note that these laboratory tests have helped to make the transfusion of blood and blood products safe today. We have seen the tragedy of hundreds of haemophiliacs who got transfused with infected blood products.
Meanwhile vaccine manufacturers are also working with might and main to produce preventive vaccines, to be administered to non-HIV positive individuals likely to be exposed and get infected with HIV, and therapeutic vaccines in order to boost resistance to the virus.
Meanwhile, the bottom line and the buzzword is prevention by whatever means one can adopt according to personal circumstances, whether physical, social, moral or religious.