HIV: Causes, Risk Factors, Symptoms, Disease Development, Clinical Manifestations, Diagnosis, Treatment and Prevention

It currently represents a significant public health concern, affecting millions of people worldwide.

HIV weakens the immune system, and it loses the natural defense capacity of the body against diseases.

This means that a person living with HIV and not receiving treatment will find it increasingly difficult to fight infections and diseases.

As the virus destroys and impairs the function of immune cells, infected people gradually become immune deficient.

Immunodeficiency results in increased susceptibility to many infections, cancers, and other diseases that people with healthy immune systems can fight.

The virus attacks the immune system and weakens its ability to fight infection and disease.

The most advanced stage of HIV is the Acquired Immune Deficiency Syndrome, commonly called AIDS; this disease can take from 2 to 15 years to develop, depending on the health conditions of each individual.


AIDS is the final stage of infection when your body can no longer fight life-threatening conditions.

With early diagnosis and effective treatment, most people with HIV will not develop AIDS.

AIDS is defined by developing certain infections or other clinical severe manifestations.

There is no cure for HIV, but there are treatments so that most people with the virus can live long and healthy lives.

Causes of HIV

HIV is found in the body fluids of an infected person, which include semen, vaginal and anal fluids, blood, and breast milk.

It is a fragile virus and does not survive outside the body for long.

The most common form of transmission is through unprotected sex.

It can also be transmitted by sharing infected needles and other equipment and from an HIV-positive mother to her child during pregnancy, delivery, and breastfeeding.

It is also possible that HIV is spread through oral sex and the exchange of sex toys, although the chances of this happening are meager.

For example, it is estimated that there is only a 1 in 5,000 chance of contracting HIV from unprotected oral sex to someone with the infection.

People cannot get it through regular everyday contacts, such as kissing, hugging, shaking hands, or sharing personal items, food, or water.

HIV cannot be transmitted through sweat or urine.

Risk factor’s

Behaviors and conditions that put people at higher risk for HIV include:

  • We were having unprotected sex.
  • We have other sexually transmitted infections such as syphilis, herpes, chlamydia, gonorrhea, and bacterial vaginosis.
  • I share syringes, IV administration equipment, and contaminated solutions when injecting drugs.
  • She received blood transfusions, tissue transplants, and medical procedures that involved unsafe or sterile cuts or perforations.
  • I am experiencing accidental needle stick injuries, especially among healthcare workers.

HIV is less viable in the external environment and less resistant to physical and chemical factors.

It is heat sensitive and can be wholly inactivated at 56 ° C for 30 minutes or 100 ° C for 20 minutes.

Pasteurization and the most commonly used chemical disinfectants include 75% alcohol, 0.2% sodium hypochlorite, 1% glutaraldehyde, 20% acetaldehyde, acetone, ether, and bleaching powder, which can inactivate HIV.

However, ultraviolet rays and γ rays cannot inactivate HIV.

Signs and symptoms

The symptoms of HIV vary depending on the stage of infection.

Although people living with HIV tend to be most infectious in the first few months, many are unaware of their status until later stages.

For the first few weeks after the initial infection, people may not experience flu-like symptoms, such as fever, headache, rash, or sore throat.

As the infection progressively weakens the immune system, an individual may develop other signs and symptoms, such as swollen lymph nodes, weight loss, fever, diarrhea, and cough.

The infected individual who does not receive treatment can develop serious diseases such as tuberculosis, cryptococcal meningitis, severe bacterial infections, and cancers such as lymphomas and Kaposi’s sarcoma, among others.

Disease development


From HIV infection to AIDS, if there is no drug treatment, it usually takes 1 to 10 years.

If HIV-infected patients are treated with highly active antiretroviral therapy as soon as possible, this period could be significantly prolonged.

In some cases, people carry HIV without developing significant AIDS.

Clinical stages of HIV infection

The course of HIV infection is divided into acute infection stage, asymptomatic infection stage, pre-AIDS stage, and AIDS stage.

Acute infections

When the human body is infected with HIV, between 50% and 70% of those infected, have cold-like or mononucleosis-like symptoms within 14 days, including fever, pharyngitis, headache, muscle and joint pain, and malaise.

Universal lymphadenectasis, maculopapular occurring on the face and torso, oral, esophageal candidiasis, nausea, vomiting, diarrhea, and other gastrointestinal symptoms are present on physical examinations.

Ulcers can also be seen on the mucosa and are the most apparent indications of differential diagnosis with other viral infections.

Less common symptoms include aseptic meningitis, acute peripheral neuritis, myelopathy, and mononeuritis multiplex.

Laboratory tests show a sharp increase in virus titer within one week, a relative decrease in the CD4 + T lymphocyte count, a relative increase in the number of CD8 + T lymphocytes, and a slight increase in platelets.

Serum levels of aspartate aminotransferase and alkaline phosphatase are slightly elevated, but clinical hepatitis is rare.

Symptoms in most patients subside within one month, and signs in some patients persist for 2 to 3 months.

Severe reductions in CD4 + cells may indicate the rapid progress of HIV infection.

HIV antibodies in the body gradually become positive 2 to 4 weeks after clinical symptoms.

The time from infection to seroconversion is the window period, usually 4 to 8 weeks, less than six months.

Asymptomatic infection

About 5% of HIV-infected people are asymptomatic for as little as 1 to 2 years, possibly due to the high concentration of virus in the infection, infection mainly by syncytium-inducing strains (X4), and a poor immune system.

People infected with HIV-1 generally have an asymptomatic stage that lasts 7 to 8 years.

In this stage, CD4 + lymphocytes have a reduction of 30 to 60 / μL on average each year but are still in the normal range, the CD4 + / CD8 + ratio is moderate, and the anti-HIV antibody in the serum is positive.

The body’s normal immune function effectively limits HIV to a low replication level, so symptoms are not noticeable.

Early AIDS

Over time, immune function gradually weakens. Patients develop enlarged lymph nodes, secondary hairy leukoplakia, oral or vaginal yeast infection, herpes zoster, and various skin lesions caused by EB virus infection.

When the CD4 + cell count is reduced from 200 to 400 / μL, and the number of HIV nucleic acids is more than 5000 / μL, symptoms develop further and manifest as severe fatigue, night sweats, and abnormal weight loss, which indicates the appearance of syndromes.


When the nucleic acid number of HIV is up to tens of thousands per milliliter or more, and the CD4 + cell count is 200 / μL or less, HIV will directly lead to the involvement of all tissues and organs multiple opportunistic infections and malignant tumors.

Due to the immature immune system in children, the clinical symptoms of HIV-infected children are different from those of adults.

In general, HIV in children develops rapidly.

Without adequate therapy, 20% of pediatric patients often develop AIDS within a year of HIV infection, and 28% die within five years.

Pneumocystis pneumonia, Candida esophagitis, disseminated cytomegalovirus infection, cryptococcal infection, and Mycobacterium avium complex are also acute opportunistic infections in children with AIDS.

Children with one year of HIV infection have significant lymphadenopathy and hepatosplenomegaly.

Disease progression, progressive encephalopathy, lymphatic interstitial pneumonia, and pyogenic bacterial infection can be seen in 30–40% of pediatric patients.

Clinical manifestations of each system


Opportunistic lung infections are seen more frequently with cytomegalovirus pneumonia.

And others are pulmonary toxoplasmosis, bronchopulmonary candidiasis, pulmonary cryptococcosis, pulmonary tuberculosis, nocardiosis, actinomycosis, and AIDS-related lung tumors such as Kaposi’s sarcoma, Non-Hodgkin’s lymphoma.

Digestive system

Presentations include watery diarrheal syndrome caused by cryptosporidium, pharyngeal and esophageal lesions caused by Candida Albicans, ulcerative colitis induced by cytomegalovirus, and malabsorption syndrome caused by Kaposi sarcoma invading the intestine, characterized by diarrhea, abdominal pain, difficulties with swallowing and abnormal weight loss.

Hematologic disorders

80% of AIDS patients are accompanied by anemia or opportunistic infections, including severe anemia, thrombocytopenia, granulopenia, decreased T lymphocytes, and increased polyclonal activation of B cells.

Lymphadenopathy and splenomegaly

Lymphadenopathy occurs in the neck, armpits, and back groin and can affect the entire body.

Lymphadenopathy can be divided into enlarged lymph nodes, contracted lymph nodes, and reduced lymph nodes.

Splenomegaly can cause death after spontaneous rupture.

Skin manifestations

Almost 100% of HIV-infected patients have skin manifestations, generally divided into four categories: inflammatory and hyperproliferative diseases, infectious diseases, parasitic infestations, and tumors.


HIV antibody testing can be done four weeks to six months after exposure.

The most common test for the detection of HIV disease is the enzyme-linked immunosorbent assay.

If the result is positive, the test is repeated on the same blood sample.

Another positive result is confirmed using a more specific test, such as Western blot.

One problem with ELISA is that it produces false-positive results in people who have been exposed to parasitic diseases such as malaria, which is particularly problematic in Africa, where both AIDS and malaria are rampant.

The emergency HIV medicine called PEP (post-exposure prophylaxis) can prevent infection if started within three days of possible exposure to the virus. It is recommended to start as soon as possible.

An early diagnosis means that you can start treatment earlier, improving your chances of controlling the condition.

HIV tests may need to be repeated one to three months after possible exposure to HIV infection (known as the “window period”).

Clinical tests can sometimes give a result in minutes, although it may take a few days to develop a more detailed blood test.

If the first test suggests HIV, a new blood test should be done to confirm the result.

If this is positive, they will refer you to the specialized HIV health area for further testing and prescribing treatment options.

Polymerase chain reaction tests, which detect viral RNA and therefore allow detection of the virus after very recent exposure, and single-use diagnostic testing are other options.

Because these tests are costly, they are often beyond the reach of the majority of the population at risk of contracting the disease.

Pharmaceutical companies are developing new tests that are less expensive and do not require refrigeration, allowing further evaluation of populations at risk worldwide.

Current serological tests can detect the presence or absence of HIV-1/2 antibodies or HIV p24 antigen.

The tests must be used in a combination and a specific order validated and based on the prevalence of HIV in the population.


Antiviral therapy is the key to treating HIV / AIDS.

With the advent of HIV protease inhibitors, applications of highly active antiretroviral therapy have dramatically increased the efficacy of anti-HIV and significantly improved the quality of life and prognosis in HIV / AIDS patients.

Antiviral drugs for HIV can be divided into three main types: nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, and protease inhibitors.

Nucleoside reverse transcriptase inhibitors

These drugs can selectively bind to HIV reverse transcriptase and be incorporated into elongated DNA strands, terminating the DNA strand elongation process and inhibiting HIV replication and transcription.

Nucleoside reverse transcriptase inhibitors include:


It is used in combination with other antiretroviral drugs.

It is very active against retroviruses, including the human immunodeficiency virus (HIV), in vitro.

It is phosphorylated by cellular thymidine kinase on zidovudine triphosphate in virus-infected cells, selectively inhibiting the reverse translocase of HIV, which results in the termination of the synthesis of the HIV chain, inhibiting the replication of HIV.

The commonly used dose is 200 mg, three times a day, or 300 mg, two times a day.

The main adverse reactions are myelosuppression causing anemia or agranulocytosis.

Other side effects are myositis, headache, nausea, and vomiting.


The dose is 0.75 mg, 3 times a day.

It is mainly used in patients with AIDS and AIDS-related complex who cannot tolerate zidovudine treatment.

It can lower serum P24 antigen levels and raise CD4 + T cell counts.

The combination with Zidovudine is synergistic to prevent the emergence of drug-resistant strains and reduce the toxic reaction.

It is indicated for adults and children with AIDS.

The main side effects include peripheral neuritis and gastritis, but not bone marrow suppression.


The standard dose is 200 mg, two times a day, and the particular amount is 125 mg, two times a day for patients whose weight is less than 60 kg.

Adverse reactions include peripheral neuritis, pancreatitis, nausea, diarrhea, and other gastrointestinal symptoms.


It is a thymidine analog that inhibits the replication of HIV in human cells.

It is phosphorylated by cellular kinases to form triphosphates.

The dose is 30 to 40 mg, 2 times a day. Adverse reactions are peripheral neuritis in some patients.


Lamivudine triphosphate does not interfere with the metabolism of normal cellular deoxynucleosides.

Its inhibitory effect on mammalian DNA polymerase α and β is weak, and it hardly affects the DNA content of mammalian cells.

It has no apparent toxicity on mitochondrial structure and DNA content.

The dose is 150 mg per day, two times per day.

It can be well tolerated, with no apparent adverse reactions.


It is used in adult patients with HIV infection and is contraindicated in patients with advanced kidney disease, liver damage, neutrophil count <750 / μL, or hemoglobin <7.5g / dL.

The dose is 300 mg, 2 times a day.


It is a mixture of Zidovudine and Lamivudine, containing 300 mg of Zidovudine and 150 mg of Lamivudine.

The dose is one tablet, 2 times a day.


It is a combination of Abacavir, Zidovudine, and Lamivudine.

Adverse reactions are nausea, vomiting, diarrhea, abdominal pain, headache, rash, fever, malaise, fatigue, neutropenia, and leukopenia.

Non-nucleoside reverse transcriptase inhibitors: These drugs can act selectively at specific sites of HIV reverse transcriptase and reduce their activity, inhibiting HIV replication.

However, these drugs are susceptible to drug resistant strains.

Non-nucleoside reverse transcriptase inhibitors


Uses in pregnant women who have not used antiretroviral therapy during labor can prevent mother-to-child transmission of HIV-1.

The dose is 200 mg per day for 14 consecutive days, then 200 mg, 2 times per day.

Side effects are visible rashes and liver dysfunction.


In doses of 300 mg per day. Side effects are nausea, vomiting, headache, and fatigue.


In doses of 400 mg, twice a day.

Side effects are visible rash and headache.


In doses of 600 mg per day. Side effects are nausea and vomiting.

Protease Inhibitors (PI)

The HIV-1 protease is an asymmetric dimer.

Under its catalysis, two HIV precursor proteins divide into a mature protein, which is why this enzyme is essential in replicating the virus.

Protease inhibitors can inhibit HIV replication by inhibiting proteases necessary in protein synthesis for HIV replication and maturation.

Protease inhibitors include:


It is an efficient and highly selective HIV protease inhibitor.

It binds to the activation points of the HIV protease so that HIV cannot bind and hydrolyze polypeptide chains.

Its target enzymes in HIV protease inhibition are different from other anti-HIV virus drugs such as Zidovudine, so there is no cross-resistant virus.

The dose is 600 mg, 2 times a day or 3 times a day.

Side effects include nausea, vomiting, diarrhea, other gastrointestinal symptoms, headache, and transaminitis.


The dose is 800 mg, 3 times a day.

Side effects are nausea, vomiting, headache, fatigue, dizziness, rash, increased unconjugated bilirubin, thrombocytopenia, kidney stones, elevated blood sugar, and lipodystrophy.

To prevent kidney stone formation, patients should drink plenty of water.


The dose is 750 mg, 3 times a day. Side effects are diarrhea and hyperglycemia.


It is an active inhibitor of the aspartic proteases HIV-1 and HIV-2, blocking the enzyme that promotes the production of polyproteins required for morphologically mature HIV particles.

So the HIV particles remain immature, delaying the spread of HIV in cells postpone the development of HIV.

The dose is 300 to 600 mg, 2 times a day.

Side effects are nausea, vomiting, diarrhea, fatigue, kinesthesis, liver dysfunction, elevated triglycerides, increased uric acid, and high blood sugar levels.

Living with HIV

The drugs, known as antiretrovirals, work by preventing the virus from replicating in the body, allowing the immune system to repair itself and prevent further damage.

These medications come in tablets, which must be taken every day.

HIV can develop resistance to a single HIV drug very quickly, but taking a combination of different drugs makes this much less likely.

Most people with HIV take a combination of 3 antiretrovirals, and the medications must be taken every day as recommended by your doctor.

For people living with HIV, taking effective antiretroviral therapy (where the HIV is “undetectable” in blood tests) will significantly reduce the risk of transmitting HIV to sexual partners.

It is rare for a pregnant woman living with HIV to pass it on to her babies, provided they receive timely and effective antiretroviral therapy and medical care.

You will also be encouraged to exercise regularly, eat a healthy diet, stop smoking and get yearly flu immunizations to minimize your risk of serious illness.

Without treatment, the immune system will be severely damaged, and life-threatening illnesses can occur.


  • Control of sexual transmission: clean and safe sex life.
  • Control of blood transmission: safe transfusion of blood and blood products.
  • Drug abuse prevention: avoid intravenous drug use.
  • Prevention of mother-to-child transmission: artificial feeding, antiretroviral treatment.
  • Prevention of accidental HIV infection: gloves, antiretroviral therapy, combination therapy.