HIV and AIDS:
signs and transmission

HIV (the human immunodeficiency virus) is a virus that causes immunodeficiency. The virus attacks the cells of the immune system (T-helper cells), rendering them unable to perform their function of fighting pathogens such as bacteria and eliminating abnormal cells. As a result, the risk of infections and other diseases, such as cancer, increases. Acquired immunodeficiency syndrome (AIDS) is the term for the final phase of HIV disease when the immune system’s ability to defend the body falls below a certain threshold, leading to the development of sometimes life-threatening diseases. If it is not treated, HIV infection is always fatal.

Different indicators occur depending on the stage of the disease. At first, HIV does not cause any symptoms. It is only after two to six weeks that symptoms similar to those of a cold or flu appear. As a result, HIV infection often goes unnoticed at first, especially because these symptoms subside after a few weeks.

The first signs are:

• Fever
• Sore throat, headache, achy limbs
• Swollen lymph glands in the neck area, swollen tonsils
• Tiredness/fatigue
• Night sweats
• Skin rash with small, red pustules, predominantly on the chest and back

As the immune system continues to weaken, the susceptibility to certain diseases increases. The following symptoms may occur:

• Fever of over 38.5 degrees
• Nerve disorders with feelings of numbness, tingling of the limbs, muscle weakness
• Diarrhoea that lasts for several weeks
• Shingles
• Fungal infections in the mouth and genital area

If you have these symptoms, it is important to take an HIV test as soon as possible.

The infectious diseases characteristic of AIDS (AIDS-defining illnesses) appear after an average of seven to twelve years (sometimes even after 20 years). The immune system is already severely damaged at this point and the number of helper cells has dropped below a defined threshold.

In addition to the aforementioned illnesses, the following are typical of AIDS:

• Bacterial pneumonia
• Infections with rare pathogens (toxoplasmosis, cryptococcus)
• Various cancers, such as Kaposi’s sarcoma (a type of skin cancer)
• Inflammation of the brain and even dementia
• Chronic herpes virus infections
• Wasting syndrome: fever and tiredness, severe weight loss, long-lasting diarrhoea (over 30 days)

AIDS can be traced back to an HIV infection. The outer layer of the HIV virus consists of a protein shell that can easily adhere to human cells due to its special surface (lock and key principle). This predominantly affects T helper cells, which are destroyed by the virus together with other immune defence cells. As a result, the immune system is weakened and otherwise harmless pathogens can enter the body more easily and cause infections. Organs may also be damaged by the virus.

HIV is relatively difficult to catch. The virus cannot be transmitted via everyday activities. Infection is only possible if a sufficient quantity of the virus enters the body. This mainly happens during sex or drug use. There are effective means of protection against transmission.
HIV can also be transmitted via the blood, such as via blood reserves during a transfusion (there is no risk of this occurring in Switzerland as blood reserves are tested). It is not possible to catch HIV via droplet infection (e.g. coughing or sneezing).

HIV is most commonly transmitted through unprotected vaginal or anal sex. Condoms, femidoms and pre-exposure prophylaxis (PrEP) offer protection. An injury to the mucous membrane or a venereal disease (e.g. syphilis or gonorrhoea) increases the risk. With successful HIV treatment, the virus is no longer detectable in the blood. HIV cannot then be transmitted even during sex.

Drug addicts can also become infected via contaminated syringes and needles while consuming drugs. Pregnant women can transmit HIV to their baby during childbirth or subsequently during breastfeeding, but there are now good ways to prevent this.