by Aejaz Iqbal
AIDS, caused by HIV, weakens immunity, spreads through specific bodily fluids and demands prevention, early diagnosis and sustained antiretroviral treatment for survival
Acquired Immunodeficiency Syndrome (AIDS) is a disease of the human immune system caused by the Human Immunodeficiency Virus (HIV). During the initial infection, a person may experience a brief spell of influenza-like illness, which is usually followed by a prolonged period without symptoms. As the illness progresses, it increasingly weakens the immune system, making individuals far more likely to develop various infections, including opportunistic infections and tumours that normally do not affect those with healthy immune systems. AIDS is currently the sixth leading cause of death among people aged twenty-five to forty-four in the United States, down from its position as the leading cause in 1995. Millions of people across the world are living with HIV/AIDS, among them many children below the age of fifteen.
HIV attacks the immune system in a way that leaves the body vulnerable to a wide range of life-threatening infections and cancers. Microorganisms such as bacteria, parasites, viruses and fungi, which pose little danger to people with strong immune systems, can cause fatal illnesses in people suffering from AIDS. The virus has been detected in saliva, tears, nervous system tissue, spinal fluid, blood, semen, including pre-seminal fluid, vaginal fluid and breast milk, but transmission has been conclusively proven only through blood, semen, vaginal secretions and breast milk.
HIV is transmitted through sexual contact, which includes oral, vaginal and anal sex; through blood, particularly in the rare case of contaminated transfusions or through needle sharing; and from mother to child during pregnancy through shared blood circulation or after birth through breast milk. Very rarely, the virus may spread through accidental needle injuries, artificial insemination with infected semen, or transplantation of infected organs. It is important to note that HIV infection is not transmitted through hugging, mosquito bites, playing sports, or touching objects previously handled by an infected person.
AIDS is not transmitted to individuals who donate blood or organs. Donors never come into direct contact with recipients, and all procedures use sterile equipment. However, people receiving blood or organs from an infected donor can become infected, which is why blood banks and organ donor programmes maintain rigorous screening of donors, blood and tissues. Those at highest risk of contracting HIV include injection drug users who share needles, infants born to mothers with HIV who did not receive therapy during pregnancy, people engaging in unprotected sex particularly with partners who have high-risk behaviours or who are HIV-positive, those who received blood transfusions or clotting products between 1977 and 1985 when screening was not yet standard, and sexual partners of individuals engaged in high-risk practices.
HIV/AIDS may manifest through unexpected weight loss, a burning sensation in the genital area, diarrhoea lasting for a month, continuous fever persisting beyond a month, ulcers in the mouth, loss of appetite, weakness, night sweats, swollen lymph glands and tuberculosis that does not respond to anti-TB medication. Social factors that contribute to the spread of HIV/AIDS include migration, industrialisation and various social and economic difficulties.
Once HIV enters the body, it multiplies rapidly, producing a high concentration of virus in the bloodstream. During the early stage of infection, the virus count can reach several million particles per millilitre of blood, accompanied by a sharp decline in CD4+ T cells. This acute phase is often marked by the activation of CD8+ T cells, which attack infected cells, and by the production of antibodies. A vigorous CD8+ T cell response is associated with slower disease progression and better outcomes, although it cannot fully eliminate the virus. Ultimately, HIV leads to AIDS by depleting CD4+ T cells, weakening the immune system and allowing opportunistic infections to take hold. In the acute phase, CD4+ T cells are lost through direct viral destruction and cytotoxic immune responses, while in the chronic phase, persistent immune activation and the gradual inability of the immune system to produce new T cells cause a steady decline in CD4+ numbers.
Much of the CD4+ T cell loss occurs early in infection, particularly in the intestinal mucosa, which contains the majority of the body’s lymphocytes. These mucosal T cells express the CCR5 protein, which the virus uses to gain entry. Although the immune system eventually imposes some control over the virus and the infection enters a clinically latent phase, HIV replication and immune activation continue, progressively weakening the immune system.
Prevention requires avoiding illicit drug use and never sharing needles or syringes, a measure supported by needle-exchange programmes that offer sterile equipment and treatment referrals. Avoiding contact with another person’s blood is essential, and caregivers of injured individuals may need protective clothing, masks and goggles. Anyone who tests positive for HIV should not donate blood, plasma, organs or sperm, and must inform sexual partners. They should also avoid exchanging bodily fluids during sexual activity and use preventive measures such as condoms, though even condoms do not eliminate all risk; abstinence remains the only completely reliable method of preventing sexual transmission. HIV-positive women wishing to conceive should seek counselling, as medications exist that drastically lower the risk of infecting the baby. In the United States, HIV-positive mothers are advised not to breastfeed to prevent transmission through breast milk.
There is no cure for AIDS, but various treatments can manage symptoms and prolong life. Antiretroviral therapy suppresses viral replication, and combinations of drugs known as Highly Active Antiretroviral Therapy (HAART) have proved highly effective in reducing viral load and improving T-cell counts. Although HAART does not eliminate HIV and people with suppressed viral loads can still transmit the virus, it significantly improves survival and quality of life. However, the virus may become resistant to treatment, especially if medication schedules are not strictly followed. Genetic tests can help determine resistance and assist doctors in selecting effective drug combinations. Long-term use of HAART can cause side effects such as fat accumulation on the back or abdomen, diarrhoea, headaches, malaise, nausea, weakness and an increased risk of heart attack due to rising cholesterol and glucose levels. Patients must be monitored carefully, with regular CD4 counts and viral load tests, to ensure that CD4 levels rise and viral levels fall to undetectable levels.
Other antiviral drugs and growth factors such as erythropoietin and filgrastim may be used to treat anaemia and low white blood cell counts associated with HIV. Medications are also used to prevent opportunistic infections when CD4 counts fall below certain thresholds.
Laboratory diagnosis of HIV/AIDS may involve Total Leukocyte Count, Tri-Dot testing, card tests, ELISA, Western Blot assay, PCR and the detection of specific protein antigens such as p24, p18 and p20.
Prevention strategies, already described earlier, remain central to controlling the spread of HIV/AIDS, with emphasis on avoiding needle sharing, preventing exposure to infected blood, informing sexual partners, using condoms and counselling HIV-positive women about pregnancy. Breastfeeding by infected mothers is discouraged, and abstinence remains the only completely effective way of preventing sexual transmission.
(The author has studied microbiology. Ideas are personal.)
