Difference Between HIV and Influenza

What is HIV?

HIV is a virus that gradually attacks the immune system, which is our body’s natural defence against illness. If a person becomes infected with HIV, they will find it harder to fight off infections and diseases. The virus destroys a type of white blood cell called a T-helper cell and makes copies of itself inside them. T-helper cells are also referred to as CD4 cells.

Symptoms of HIV

You cannot rely on symptoms to tell whether you have HIV. The only way to know for sure if you have HIV is to get tested. Knowing your status is important because it helps you make healthy decisions to prevent getting or transmitting HIV.

The symptoms of HIV vary, depending on the individual and what stage of the disease you are in: the early stage, the clinical latency stage, or AIDS (the late stage of HIV infection). Below are the symptoms that some individuals may experience in these three stages. Not all individuals will experience these symptoms.

Causes of HIV

HIV infection is caused by the human immunodeficiency virus. You can get HIV from contact with infected blood, semen, or vaginal fluids.

Most people get the virus by having unprotected sex with someone who has HIV.
Another common way of getting it is by sharing drug needles with someone who is infected with HIV.
The virus can also be passed from a mother to her baby during pregnancy, birth, or breastfeeding.
HIV doesn’t survive well outside the body. So it can’t be spread by casual contact like kissing or sharing drinking glasses with an infected person.

What is Influenza?

Influenza is an acute viral infection of the respiratory tract which is considered to be one of the life-threatening infectious diseases. In certain countries, seasonal influenza affects up to 40% of the population every year, with the worldwide death toll of 500 million people. The virus can be transmitted by direct contact with infected individuals, via contaminated objects (also called fomites) and by inhalation of virus-laden aerosols.

An unexpected emergence of a new and highly virulent influenza virus strains can result in a world-wide pandemics with high morbidity and mortality  such as the “avian flu” in 1997 and “swine flu” in 2009. Throughout history, some influenza pandemics were extremely devastating; for example, the 1918–1919 influenza pandemic has killed more people in absolute numbers than any other disease outbreak in history.

Symptoms of Influenza?

People who have the flu often feel some or all of these signs and symptoms:

• Fever* or feeling feverish/chills
• Cough
• Sore throat
• Runny or stuffy nose
• Muscle or body aches
• Headaches
• Fatigue (very tired)
• Some people may have vomiting and diarrhea, though this is more common in children than adults.

*It’s important to note that not everyone with flu will have a fever.

Causes of Influenza

Influenza viruses cause the flu and are divided into three types, designated A, B, and C. Influenza types A and B are responsible for epidemics of respiratory illness that occur almost every winter and are often associated with increased rates of hospitalization and death. Influenza type C differs from types A and B in some important ways. Type C infection usually causes either a very mild respiratory illness or no symptoms at all; it does not cause epidemics and does not have the severe public-health impact of influenza types A and B. Efforts to control the impact of influenza are aimed at types A and B, and the remainder of this discussion will be devoted only to these two types.

Influenza viruses continually change over time, usually by mutation (change in the viral RNA). This constant changing often enables the virus to evade the immune system of the host (humans, birds, and other animals) so that the host is susceptible to changing influenza virus infections throughout life. This process works as follows: A host infected with influenza virus develops antibodies against that virus; as the virus changes, the “first” antibody no longer recognizes the “newer” virus and infection can occur because the host does not recognize the new flu virus as a problem until the infection is well under way. The first antibody developed may, in some instances, provide partial protection against infection with a new influenza virus. In 2009, almost all individuals had no antibodies that could recognize the novel H1N1 virus immediately.

Difference Between HIV and Influenza

Human Immunodeficiency Virus infections are an array of conditions caused by the Human Immunodeficiency Virus (which is actually a retrovirus or RNA virus) that leads ultimately to the condition of Acquired Immunodeficiency Syndrome. This indicates that the infection spreads in a cascade manner leading to a destruction of the immune cells of our body, causing the condition of acquired immunodeficiency. The initial reactions of HIV are flu like symptoms which becomes asymptomatic with disease progression, however leading to immunodeficiency.

The late stage of HIV infection is referred to as AIDS. Under this immunodeficient condition an HIV infected individual suffers from bacterial pneumonia (caused by Pneumocystis carnii), weight loss and Kaposi’s sarcoma. The disease spreads through sexual contact (and even oral and anal sex), blood contact through transfusion, skin cuts, and through any open areas in the body that comes in contact of blood or semen of the affected person.

The pathophysiological basis of the disease is a decrease in the CD4 helper T-cells. A decrease in T helper cells decreases the immune response. This is because decreased T helper cells on one hand will not cause clonal expansion and differentiation of B lymphocytes leading to a decrease in humoral immune response. On the other hand a decrease in T helper cells will also cause a reduction in the release of Interleukin-2. Reduced levels of interleukin-2 will fail to activate and proliferate CD8 cells, which are cytotoxic T cells.