Introduction: Virology and Classification
HIV, a member of the class of viruses called retroviruses (their genetic material is ribonucleic acid, abbreviated RNA instead of Deoxyribonucleic acid, DNA, like most organisms), is the virus that causes AIDS (Acquired Immunodeficiency Syndrome). Known in full as human immunodeficiency syndrome, HIV exists as two major strains; HIV-1 and HIV-2 and is believed to have a simian source (Tang, 2009). Basically, HIV originated from simian immunodeficiency syndrome commonly found with chimpanzees and certain species of monkeys inhabiting Western Africa. The two strains of HIV, HIV-1 and HIV-2, were discovered in 1983 and 1986 respectively before being discovered in human blood in the years 1931 and 1940, in the same order.
The virology of the virus majorly focuses on the replication process. The virus according to Fan, Conner and Villarreal (2011) is an “obligate intracellular parasite” that cannot replicate outside the host’s cell and has two viral proteins that aid in its attachment to the host’s cells. Fan, Conner and Villarreal (2011) further affirm that the virus only attaches to susceptible cells of the host mostly through specific routes; oral cavity, genital tract and wounded areas on the skin surface. The initial attaching surface of the virus is conventionally called the primary site, and serves as the original site from which the virus spread to other sites, hereby called secondary sites. The structure of HIV, as mentioned earlier has a proteins coating which contain various virus specific enzymes as well as a protein viral envelope, all coded by three basic genes; gag genes, pol genes and env genes (Fan, Conner & Villarreal, 2011).
Manifestation of HIV/AIDS
The clinical manifestations of HIV/AIDS are, to a great extent, associated to immunologic damage caused by the virus and not due to the effect of the virus itself. According to Baveja and Rewari (2004), the manifestation of HIV occur in four cardinal phases; Acute HIV syndrome phase, Asymptomatic phase, persistent lymphadenopathy phase and Symptomatic phase. The Acute phase occurs in the initial weeks of infection and is characterized by fever, lymphadenopathy and rash that disappear after four to five weeks into infection. Afterwards, the patient might live for years without experiencing any HIV related syndromes if not mild lymphadenopathy. This is known as the asymptomatic phase- during this phase the infection gradually progresses to chronic viral infection (Baveja & Rewari, 2004). After the asymptomatic phase comes the persistent lymphadenopathy phase characterized by constant mild lymphadenopathy. Some patients may experience chronic lymphadenopathy depending on their immune system. The persistent lymphadenopathy phase acts as an indication that the infection is almost progressing to the symptomatic stage; the most advanced phase in which various ailments are experiences in the major body systems like the respiratory system, endocrine system, gastrointestinal systems, among others.
The patients in symptomatic phase, according to Tang (2009) develop AIDS-defining illnesses and a plethora of opportunistic infections that come as a result of a weakened immune system. It is worth noting that the weakening of the immune system is attributed to the reduction in the number of Cluster of Differentiation-4 cells, trivially known as CD4 cells as a result of being destroyed by the HIV. CD4 cells are co-receptors that assist the T- cell receptor in the defending the body against pathogen invasion hence if there number reduce hence rendering the victim vastly immune-compromised.
Epidemiology of HIV AIDS
AIDS is most commonly found with sexually promiscuous individuals, commercial sex workers and drug users who share needles. Moreover, AIDS is also particularly prevalent with gay men who have anal intercourse (WHO, 2007). By the year 2007, according to the World Health Organization (2007), a total of 33 million people were living with aids. Of the 32 million people, about 30 million were adults while remaining were children. Deaths attributed to AIDS were about 2.2 million; about 1.5 million adults and 300 000 children in the same year (WHO, 2007). Again, 2007 only, 2.1 million new people of which 1.7 of them were adults were infected with AIDS (WHO, 2007). The Sub-Saharan is this worst affected region with the AIDS pandemic with most AIDS related death occurring in the same region. Conversely, the World health organization attests the percentage population with HIV/AIDS has remained relatively constant (WHO, 2007).
Diagnosis and Management
The diagnosis of HIV centers on clinical assessment followed by confirmatory HIV tests. Clinical assessment involves the scrutiny of a patient’s medical history as well as signs and symptoms. Signs and symptoms of HIV infection are numerous. However, the main symptoms of HIV can be instituted depending on the phase of the infection. As asserted earlier, the most common symptoms of HIV infection are fever, lymphadenopathy and rash. Other symptoms depend on the type of AIDS-defining illness as well as opportunistic infections that the patient suffers from. Most of these symptoms are manifestations of advanced immune deficiency.
The decision regarding who to test and who not to test solely rests with the doctor concerned, with several ethical considerations such as confidentiality and counseling upheld (Baveja & Rewari, 2004). In most cases, the doctor carries out a physical examination to the patient involving a comprehensive examination of the skin, mount, throat and lymph nodes. Physical examination is then followed by the use of screening assays tests to detect HIV. According to Baveja, and Rewari (2004), the most common tests available for diagnosing HIV are; Antibody Enzyme Immunoassay (EIA), Enzyme Linked Immunosorbent Assay (ELISA), Immunofluorescent Assay (IFA), Western Blot (WB), Immunoblot (IB) and Recombinant Immunoblot Assay (RIBA). These tests can be carried out on blood samples and other body fluids like saliva and Urine. Other tests include; p-24 antigen assay, plasma viral load detection which makes use of methods like Quantiplex and Amplicor monitor (Baveja & Rewari, 2004).
Unfortunately, there exists no proven cure or vaccine of this disease that continues to spread relentlessly. In most cases, antiretroviral drugs are given to HIV patients to improve their immune systems. There are several antiretroviral drugs available for this purpose. Kane writes that the earliest form of an antiretroviral a drug was drug that inhibited the HIV reverse transcriptase enzyme but was effective for only a short period of time. Others include Azidothimidine (AZT) treatment drugs that are mostly preferred for patients with full blown AIDS as they limit the formation of new HIV virions. As Tang affirms, currently, there exist drugs that can aid in reducing the impact of HIV/AIDS. According to Tang (2009), the working mechanisms of the drugs are based on the principle of “false-substrate”.
Baveja, U. K. & Rewari, B. B. (2004). Diagnosis and Management of HIV/AIDS: A Clinician's Perspective. New Delhi: Bi Publications PVT LTD.
Fan, H., Conner, R. F., Villarreal, L. P. (2011). AIDS: Science and Society. Sudbury, MA: Jones and Barlett Pulishers.
Tang, J. W. Human Immunodeficiency Syndrome (HIV) and Acquired Immunodeficiency Syndrome (AIDS). In Shetty, N., Tang, J. W. Andrews, J., Infectious Disease: Pathogenesis, Prevention and Case Studies (pp. 476- 490). West Sussex: John-Wiley and Sons.
World Health Organization. (2007). “AIDS Epidemic Update.” UNAIDS 4. Retrieved From http://data.unaids.org/pub/epislides/2007/2007_epiupdate_en.pdf