Providing help for people with HIV and AIDS

Archive for the ‘ Definitions ’ Category

HIV/AIDS Disease

1 comment

AIDS stands for Acquired Immune Deficiency Syndrome. “Acquired” means not innate nor inherited but transmitted from person to person; “Immune” is the body’s system of defense; “Deficiency” means not working to the appropriate degree; and “Syndrome” means a group of sings and symptoms. AIDS is the advanced stage of HIV infection. It is a disabling and deadly disease caused by HIV. Because HIV progressively destroys the immune system, without any treatment most people, particularly in resource-constrained settings, will die within a few years of the first signs of AIDS.

After the HIV virus enters a person’s body, it infects and starts to replicate in the person’s cells (essentially CD4 T cells and macrophages). It is believed that in a small number of people, HIV may enter a latent phase with limited replication. In the majority of people, the replication is significant and infection with HIV induces the body’s immune system to produce antibodies specific to HIV. The period between the acquisition of the infection and the production of HIV detectable antibodies is called the “window period”. The window period can last for 2-12 weeks. During this period the person is highly infectious but may not test positive on common HIV antibody tests. Up to 30-50% of people have a recognizable acute illness at the time to infection characterized by fever, lymphadenopathy) enlargement of lymph nodes), night sweats, skin rash, headache, and cough.

HIV-infected people may remain symptomatic for periods to as long as 10 or more years. People in this phase potentially play an important role in the transmission of HIV as they remain infectious and can be identified only by screening their scrum for HIV antibodies. After a variable period of time that varies from one individual to another, viral replication resumes and is accompanied by a destruction of CD4 lymphocytes and other immune cells resulting in a progressive immunodeficiency syndrome. The progression depends on the type and factors as that may cause faster progression including age less that 5 years, or over 40 years, other infections and possible genetic (hereditary) factors. As HIV infection progresses and immunity declines, people become more susceptible to opportunistic infections (Ols). The three most commonly reported Ols in South East Asia are tuberculosis (TB), Pneumocystis carinii pneumonia and extra pulmonary cryptococcosis (usually meningitis).

WHO has proposed a clinical staging system for HIV infection and disease in adults and adolescents in 1989 in four clinical stages. In addition to the signs, symptoms and diseases, physical activity was added to the framework using the performance scale, a modification of the Eastern Co-operative Oncology Group score. Patients are classified according to the presence of the clinical condition, or performance score, belonging to the highest stage. The staging system is hierarchic: once a stage is reached, the patient cannot revert to a lower stage, he/she can only progress to a higher once. A laboratory axis measuring CD4 count was introduced in 1990.

Rates of progression to AIDS are influenced by plasma viral load and CD4 T cell count. The higher the viral load (the amount of virus in the body) the lower the CD4 count and the higher the chances of progressing to AIDS and death. Death may be due to HIV, Ols, or malignant diseases. The prevention and better management of opportunistic infections can have a beneficial impact on the progression of HIV infection.

What is HIV

1 comment

Human Immunodeficiency Virus (HIV) is the virus that causes AIDS. Two types of HIV are currently known: HIV-1 and HIV-2. World wide, the predominant virus is HIV-1. Although cases of HIV-2 have been reported in several parts of virus are transmitted by sexual contact, through blood, and from mother-to-child during pregnancy, delivery, or breast feeding. They both appear to cause clinically indistinguishable AIDS. However HIV-2 is less easily transmitted and the period between initial infection and illness is longer than in HIV-1 cases. Cases of concurrent infections with the two viruses have been described in West Africa.

HIV belongs to the family of retroviruses. Like all retroviruses HIV contains RNA in its core and to live and replicate it needs a host cell. HIV preferentially infects a specific subset of white blood cells (CD4) that are fundamental in the immune defense system of the human body. Once the contact is made between the virus and the human cell, the virus transfers its RNA into the human cell. The RNA is transformed with the help of a substance (enzyme) called reverse transcriptase into DNA that is inserted into the human cell’s DNA to become an integral part of the human cell’s genetic material and therefore making the infection permanent.

Outside of the human body, HIV is easily destroyed. Heat (temperature higher than 60o centigrade) and various disinfectants such as formaldehyde, bleach, alcohol, acetone, phenol, and others are effective ways to destroy HIV.