HIV: definition, causes, symptoms, diagnosis and transmission

By Cristiano Antonino On May 9, 2023

HIV is a virus that attacks and destroys, in particular, a type of white blood cell, the CD4 lymphocytes, responsible for the body’s immune response

Progressively with HIV, the immune system is increasingly weakened, to the point of no longer being able to defend itself from the attack of other viruses, bacteria, protozoa, fungi and tumors.

In fact, HIV infection does not have its own specific symptoms, but develops through the effects it causes on the immune system.

The infection can be silent for years, without the manifestation of any symptoms, and one can only realize that one has contracted it following the onset of the so-called “opportunistic” disease.

Genesis of the HIV virus

From an epidemiological point of view, it is believed that the first HIV infection occurred in Africa towards the end of the 1950s, following the spillover – i.e. leap of species – of the virus which induces a state of progressive immunodeficiency.

HIV would therefore represent the mutated version of the SIV (Simian Immunodeficiency Virus) that has been living with monkeys for many hundreds of years.

To date, there is still no cure or vaccine to eradicate the infection.

However, in more than 40 years of living with this pathology on a global scale, enormous scientific advances have been made.

Today, in fact, people with HIV are able to lead an almost normal life

This is possible thanks to the use of effective therapies given by the combined action of antiretroviral drugs.

These medicines allow a recovery of immune system functionality and therefore a slowdown in the progression of the disease.

The importance of early diagnosis

Scientific evidence says that life expectancies for those who discover they have HIV today, and start treatment immediately, are comparable to those of those who are not affected by it.

The execution of the HIV test, carried out anonymously and quickly by law, is therefore a very important tool (the only one) for the early diagnosis of this syndrome.

The test – known as ELISA – consists of a simple, painless, fast, anonymous blood sample that can be administered free of charge at hospitals and authorized public/private diagnostic centres.

The presence of HIV antibodies in the blood is called HIV seropositivity.

Although current therapies are capable of offering good quality to the person affected by HIV, the social stigma (also fueled by a lack of information on the subject) undoubtedly influences the psychological well-being and the therapeutic path of the patient.

HIV commonly develops through two different stages

In the first, a few weeks after infection, patients can experience flu-like symptoms, skin manifestations and night sweats.

Sometimes even this very first phase is totally asymptomatic and is typically followed by a period, even very long (8-10 years), in which the infection remains latent, without generating any disturbance.

In the second phase, the so-called “opportunistic” diseases can arise.

Namely caused by viruses, bacteria or pathogenic fungi which, in subjects with a not seriously damaged immune system, would not cause any syndrome.

Among these are also some particular neoplasms facilitated by a strongly compromised immune response.

More specifically, one can distinguish between:

Acute primary infection
About 1 to 4 weeks after contracting HIV, more than 80% of people experience some symptoms, which can include
fever
skin rash or rash joint pain
myalgia (muscle aches)
asthenia (feeling of fatigue)
sore throat and/or oral candidiasis
swollen lymph nodes

More rarely, they also appear:

heachache,
nausea and vomit,
enlarged liver/spleen,
weight loss,
oral candidiasis
neurological symptoms comparable to meningitis (indication of the presence of the virus in the central nervous system).

Very few cases in the world have been linked to the development of a facial paralysis.

Each disorder evaluated individually is nonspecific.

It is rather the combination of the various symptoms that must give rise to clinical suspicion in cases of subjects with risky behaviour.

Without the execution of a specific test for HIV, it is not possible to diagnose an acute infection taking into account only the symptomatic picture found.

As mentioned before, in some cases the acute primary infection is even asymptomatic.

This initial phase ranges from 1 to 4 weeks and, if present, symptoms usually resolve spontaneously.

During this stage of the infection, the immune system in the gut suffers the most significant damage.

Such damage will cause “intestinal bacterial translocation”.

This phenomenon is responsible for the chronic inflammatory state typical of HIV disease

Individuals in the acute phase are the main vehicles of HIV infection.

Both because they are often unaware of their status and because in this phase of the disease the viral load is typically very high.

In response to acute infection, the immune system tries to react to the replication of the virus by producing anti-HIV antibodies, triggering the so-called seroconversion process.

Possible cures

During this initial phase of infection, for the first 3-4 weeks after infection, the HIV antibody-only screening test (ELISA) may still not be positive.

To this end, it is advisable to administer combined tests that simultaneously detect the presence of both anti-HIV antibodies and the viral antigen, called p24.

Since it may take several weeks for HIV antibodies to be detectable, the test should be repeated at least 4 weeks after the risky contact.

If unsuccessful, do another one after 3 months to dispel any doubts.

The period in which antibodies are not yet detectable is called the “immunological window”.

In this case, as mentioned, in order to diagnose HIV, other tests must also be used, such as the qualitative or quantitative PRC of HIV on plasma or lymphocytes.

Latency stage

After the acute phase, many people spontaneously begin to feel better.

In principle, the HIV virus may not generate major disturbances for a very long time window, ie even 8-10 years.

In this period, however, the virus is active and, through replication in the blood and in the body, continues to cause damage to the immune system, significantly compromising it.

Symptomatic HIV infection, AIDS (Acquired Immune Deficiency Syndrome)

In this last phase, in which the immune system is extremely compromised, the progression of the HIV infection to AIDS is recorded if the appropriate treatment has not been intervened.

AIDS, the Acquired Immune Deficiency Syndrome, makes it probable that serious infectious or neoplastic pathologies called “opportunistic” will occur.

Opportunistic infections are caused by microorganisms usually present in the environment, non-pathogenic for subjects with intact immune defenses.

However, they can also cause serious illnesses in patients with immunodeficiency.

At this stage, symptoms include:

weight loss
chronic diarrhea
night sweats
feverish states
persistent cough
tremor
mouth and skin problems
recurring infections
serious pathologies

It is sometimes mistakenly thought that HIV and AIDS are the same thing

In reality, AIDS certainly cannot be defined as an independent pathology.

Its clinical manifestations are non-specific and represented by opportunistic diseases and certain types of tumors (such as lymphomas), facilitated by serious damage to the immune system by the HIV virus.

The most common opportunistic infections that identify AIDS are:

Pneumocistis girovecii pneumonia
cerebral toxoplasmosis
esophageal candidiasis
cytomegalovirosis
visceral leishmaniasis

The most common tumors characterizing AIDS are:

primary cerebral lymphoma
Burkit’s lymphoma
Kaposi’s sarcoma
cervical cancer
cancer of the anus

If an HIV-infected person develops certain opportunistic diseases (due to serious damage to the immune system), he or she can be defined as having AIDS.

While in the past this condition of immunological damage was irreversible, today even a person with AIDS can benefit from antiretroviral therapies and can achieve a good recovery of the immune system.

The earlier the HIV diagnosis is made and appropriate treatment is started, the greater the positive effects in terms of health and life expectancy.

In the not too distant past, HIV was considered to all intents and purposes a fatal disease, today it is comparable to a serious chronic disease that requires constant and careful follow up.

HIV transmission

HIV can only be transmitted through the following body fluids from people with HIV who are unaware of or not on effective antiretroviral therapy:

semen and vaginal secretions (through intercourse)
blood and its derivatives (exchange of syringes or sharing of tools for the use of psychoactive substances; transfusion of infected blood)
breast milk (vertical transmission); in reality, for this type of contagion breastfeeding is the rarest method, while the transmission of the infection during pregnancy or at the time of delivery is more frequent.

The possibility of transmitting HIV infection depends on the type of behavior and, above all, on the amount of virus (viral load) present in the blood or in the genital secretions of the person with HIV.

It is highest in the first weeks after infection.

It is nothing when a person with HIV is on effective medications.

These treatments persistently maintain the viral load (i.e. the amount of virus present in the blood/secretions) at unmeasurable levels for at least 6 months.

In this case we speak of U=U Undetectable = Untransmittable (ie Non detectable = Not transmissible).

The degenerative process triggered by the HIV virus on the immune system can potentially progress to decree the clinical death of the patient.

The therapies

However, as already highlighted, thanks to the enormous scientific progress achieved since the beginning of this epidemic, people living with HIV today have good life expectancies.

This is thanks to antiretroviral therapy which involves the combination of drugs capable of blocking the replication of the virus by slowing down the destruction of the immune system.

By experiencing a lower impact on the body and reduced side effects, patients benefit from a good quality of life thanks to a virus under control.

Expectations are in fact similar to those who do not have HIV infection (in the event, however, that an early diagnosis has occurred).

Fortunately, it is now also possible to reduce the risk of vertical transmission (from mother to child) if antiretroviral therapy is administered to the mother during pregnancy.

The same therapy will be administered to the newborn in the first 4/6 weeks of life.

It is therefore necessary to be tested for HIV before or early in pregnancy.

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