HIV/AIDS: Human Immuno Deficiency Virus, Mode of Transmission, Stages of Infection, Symptoms, Diagnosis, Prevention, Treatment, NACO, Practice Problems, and FAQs

You all heard a lot about AIDS. You might have seen lots of advertisements and awareness programs related to AIDS on television. Have you ever seen an advertisement on TV about AIDS in which they show people believe in a myth that it spreads through a mere physical contact like touch or having lunch with the infected person. Do you think this is true? No, you are correct. AIDS will not get transmitted like that. This is totally a myth only. AIDS is a sexually transmitted disease that transmits either through unprotected sexual intercourse or through body fluids. 

People often tend to hide the fact that they are HIV positive because there is a lot of social taboo and stigma associated with HIV and AIDS which mainly arises due to the lack of awareness. Most people are under the impression that AIDS spreads through regular or sexual contact only and thus are in fear of being near a HIV positive person. This is one of the major reasons why HIV positive individuals are alienated and shunned by society for their condition. Also the fact that HIV can be transmitted during sexual intercourse creates a lot of judgement against the lifestyle and life choices of a HIV positive individual.

AIDS is a deadly disease if left untreated. Approximately 5 to 9 lakh individuals worldwide per year die because of AIDS. 

                                                       Fig: AIDS is deadly

Do you know how HIV is transmitted from one person to another or what are the common symptoms, preventive measures and treatment methods of AIDS? Let’s find out the answers for all these questions in this article.

Table of contents

• AIDS
• Human Immuno deficiency Virus (HIV)
• Mode of transmission
• Stages of AIDS 
• Symptoms of AIDS
• Diagnosis
• Prevention and care
• Treatment
• NACO
• Practice Problems
• FAQs

AIDS (Acquired Immuno Deficiency Syndrome)

AIDS stands for Acquired Immuno Deficiency Syndrome which is caused by the Human Immuno deficiency Virus (HIV). HIV infects and destroys helper T-lymphocytes and macrophages in the human body which weakens the immune system. Hence this virus causes a deficiency in the immune system and leads to a group of symptoms (syndrome). As the name says this is not a congenital disease and the person acquires it during their lifetime.

History of AIDS

Acquired Immuno Deficiency Syndrome or AIDS was first identified as a new disease in 1981 when an increasing numbers of young homosexual men succumbed to an unusual opportunistic infections and rare malignancies in USA. Human Immuno deficiency Virus type 1 (HIV-1), was later identified as the causative agent of this condition. It was identified by Prof. Luc Montagnier and Prof. Robert Gallo independently in 1984. 

HIV was first discovered in primates and over the ages, it eventually spread to humans. Even though the illness had long been present, it was not clinically identified until the 1980s. Since then, it has spread throughout the entire world and has claimed the lives of almost 25 million people. In India HIV infection was first reported in 1986 among some prostitutes of Chennai. 

Although they are not directly connected, the terms AIDS and HIV are sometimes used interchangeably. Human Immuno deficiency Virus is referred to as HIV. If the virus is not treated, it causes Acquired Immuno Deficiency Syndrome or AIDS. HIV cannot be totally eliminated by the human body, unlike certain other viruses, even with treatment. Therefore, there is currently no cure for HIV after it has been acquired. 

Human Immuno deficiency Virus

Lentiviruses are a subgroup of retroviruses that include the Human Immuno deficiency Virus (HIV). It results in HIV infection, which eventually causes AIDS (Acquired Immuno Deficiency Syndrome). A person with AIDS loses their immune function, which allows malignancies and life-threatening diseases to spread throughout their body. The specific subset of WBCs (white blood cells) like T-helper cells and macrophages are destroyed by HIV. Inside these cells, this virus replicates. The other name of T helper cells is CD4 cells. Depending on the subtype of HIV, a person with HIV has an average survival time of nine to eleven years without therapy. HIV can be found as both free virus particles and as a virus inside infected immune cells. 

Types of Human Immuno deficiency Virus

There are two lentiviruses, Human Immuno deficiency Virus type 1 and 2 (HIV-1 and HIV-2) which cause AIDS.

HIV-1

It is the most common type of virus that is found worldwide. It is further categorised into four types as follows:

• Group M
• Group N
• Group O
• Group P

Group M

The letter ‘M’ stands for ‘major’ which suggests that this particular strain of HIV is responsible for 90% of all cases of AIDS worldwide. This group of viruses includes 11 subtypes (A to K).

Group N

The letter ‘N’ stands for ‘non-M, non-O’. There had only been ten Group N illnesses discovered as of 2006, according to the statistics.

Group O

The letter ‘O’ denotes the ‘Outlier’ HIV group. Usually, this virus is only seen in West-central Africa.

Group P

In 2009, a new case of the virus was discovered. The Group P virus has only been discovered in one case so far. This is due to the fact that this virus mostly affects simians (apes and monkeys). This virus has been discovered from a Cameroonian woman. Group P originated from gorillas.

HIV-2

Western Africa accounts for the majority of cases of this virus. There are 8 recognised HIV-2 subgroups (A to H). Simian Immuno deficiency Virus, which is prevalent in a species of monkey, and HIV-2 are closely related.

Retroviruses 

Retroviruses comprise a large group of RNA viruses. HIV belongs to this group of viruses. Their genetic material is composed of two linear ssRNAs. The characteristic feature of this group of viruses is the presence of an enzyme called reverse transcriptase. Reverse transcriptase is used to convert the viral ssRNA into viral dsDNA by a process called reverse transcription and the subsequent integration of the viral dsDNA into the host genetic material. 

                                                             Fig: Retroviral genome

The simplified structure of the linear genome of retroviruses reveals the presence of three genes, enzymes and LTRs. They are listed below:

• Gag - Codes for structural proteins.
• Pol - Codes for enzymes required for reverse transcription and integration into the host cell genome.
• Env- Codes for viral envelope glycoproteins,
• LTR - Long terminal repeats flanking the 3’and 5’ end of genes for protection. 
• Enzymes - Two single stranded RNAs associated with the reverse transcriptase enzymes. 

Structure of HIV

The Human Immuno deficiency Virus or HIV is a retrovirus and thus its genetic material is composed of ribonucleic acid or RNA. It is a spherical enveloped virus of about 19 - 120 nm in diameter. The outermost layer is an envelope made up of a lipid bilayer which consists of a large number of knob-like spikes with pedicels made up of viral glycoproteins (gp). The protein coat surrounds the genetic material which is in the form of 2 identical copies of ssRNA. Associated with the 2 viral ssRNA strands, there are 2 molecules of an enzyme called reverse transcriptase present.

              Fig: Structure of Human Immuno deficiency Virus 

Reverse transcription in Human Immuno deficiency Virus 

Being a virus, HIV needs a host to multiply and after entry into the host cell, the reverse transcriptase enzyme catalyses the conversion of its RNA genome into double stranded viral DNA which gets integrated into the host genome. This process is known as reverse transcription. 

The viral DNA then directs the host cell to assist the formation of viral particles. After assembly of the viral particles, the lysis of the host cell releases the viruses. HIV attacks the immune cells and thus severely damages the immune system in this way.

                                          Fig: Reverse transcription

 Life cycle of the Human Immuno deficiency Virus (HIV)

The life cycle of the Human Immuno deficiency Virus (HIV) when it attacks the immune cells like T cells and macrophages in the human body reduces their number and creates a severe immune deficiency in the body. This makes the patient vulnerable to death from opportunistic infections (infection caused due to microbes that cannot cause a disease when the immunity is strong).

HIV is a retrovirus (A) and it contains 2 single stranded genomic ribonucleic acids (RNA). It infects the macrophages and helper T lymphocytes (host cells) in the human body (E). The retrovirus infects the cells by injecting its single stranded genomic RNAs (C), then the reverse transcriptase enzyme (B) catalyses the conversion of its RNAs into double stranded viral DNA (D). This process is known as reverse transcription.

The viral DNA gets integrated into the host genome and directs the host cell to assist the formation of viral genomic RNAs and messenger RNAs (mRNA) molecules that help in forming viral proteins using host ribosomes. The transcribed genomic RNA and viral proteins are assembled to form viral particles. This is how a retrovirus like HIV replicates and multiplies within the human body.

                     Fig: Life cycle of the Human Immuno deficiency Virus

Reason for impared acquired immunity in HIV infection

Acquired immunity refers to the type of immunity a person acquires after birth by exposure to different types of antigens. It has two components such as humoral immunity or antibody mediated immunity and cell-mediated immunity or CMI. T lymphocytes form a major component of CMI and HIV attacks the T lymphocytes called T helper cells. The infected helper T lymphocyte’s machinery used by the virus for multiplication. So their number will decrease in the body due to viral multiplication and release of viral particles by breaking the T cells. T helper cells are required for the activation of B lymphocytes to produce the antibodies. So both humoral and cell-mediated immunity are affected. Hence the acquired immune response is impaired in AIDS.

                                                    Fig: HIV infects T cells

Mode of transmission

Only direct contact with specific body fluids from an HIV-positive person who has a detectable viral load can result in the transmission of HIV. These liquids are as follows: 

• Blood
• Semen
• Pre-seminal fluid
• Rectal fluids
• Vaginal fluids
• Breast milk

The HIV in these fluids must enter an HIV-negative person's circulation via a mucous membrane found in the rectum, vagina, mouth, or tip of the penis, normally through open cuts or sores, or by direct injection for transmission.

              Fig: Common entry points of HIV

Through unprotected sexual intercourse

Having anal or vaginal sex without properly using a condom can result in the transmission of HIV. HIV transmission during anal sex is more prevalent than during vaginal sex.

Through infected needles

Sharing injecting tools, such as needles and syringes or catheters with an HIV-positive person without proper sterilisation can transmit viruses as these tools may contain blood and body fluids which can carry HIV. This normally happens in people who inject hormones, silicone, or steroids using shared syringes or needles.

Through blood transfusion and transplants

Receiving HIV-contaminated organs or tissue transplants, blood transfusions, or blood products cause AIDS. Nowadays, due to extensive testing of the blood samples, donated organs and tissues, the risk is extremely low.

Through breastfeeding or pregnancy

A mother who is HIV-positive passes the virus to her child during breastfeeding or giving birth. However, using medications against HIV and other methods has reduced the danger of prenatal HIV transmission.

                                                    Fig: Mode of transmission of HIV

Stages of AIDS

If HIV infection is left untreated, it typically goes through the following four stages:

• Acute infection
• Latent infection
• ARC (AIDS-related complex)
• Acquired Immuno Deficiency Syndrome (AIDS)

Acute HIV infection

HIV symptoms can appear 2 – 4 weeks after the virus enters the body and might continue for days or weeks. During this period of acute infection, people experience a number of symptoms, such as fever, fatigue, skin rashes, muscle aches, sore throat, nausea, vomiting, ulcers in the mouth or genitals and many more. This period is known as the seroconversion phase. The body starts making antibodies against HIV in this phase. The body normally reacts in this way when it detects an infection. During this stage, the blood usually contains a lot of HIV. The virus has a significant risk of spreading because of its quick replication. Some people experience mild flu-like symptoms during this stage.

Latent infection

In this second stage, HIV still causes harm to immune cells but multiplies at very low levels within the body. Usually, during this stage, no one becomes ill with the virus or exhibits any symptoms. The term ‘clinical latency’ or ‘asymptomatic HIV infection’ are other names for this stage. The latent stage of HIV infection can last for ten years or longer without treatment. It depends on the age, immunity and health of the affected person. During this time, the virus can still spread from one person to another. The progression of HIV can be slowed down or stopped by antiretroviral medication in this stage.

ARC (AIDS-related complex)

The ARC or AIDS-related complex is a mild symptomatic stage in which symptoms start to appear. Several illnesses occur due to damage to the immune system. The common symptoms include weight loss, fever, malaise, unexplained diarrhoea that lasts for months, bacterial infections, and night sweats. Mild infections such as oral thrush, general lymphadenopathy, and enlarged spleen can also occur in this stage. 

Acquired Immuno Deficiency Syndrome (AIDS)

Stage 4 is the most severe infection stage referred to as AIDS. When an individual's immune system is severely compromised and unable to fight against new infections, this stage occurs. The symptoms involved in stage 4 are weight loss, night sweats, fever, skin problems, chronic diarrhoea, mouth problems, and serious illness. If a person's CD4 blood count falls below 200 cells per cubic millilitre (cells/mm3) or if they experience an opportunistic infection, a healthcare provider may determine that they have stage 4 HIV.

Symptoms of AIDS

The signs and symptoms of HIV infection can vary from person to person and, in rare situations, a patient may not exhibit any symptoms at all. Typical HIV warning signs and symptoms include fever, joint pain, chills, headache, muscle ache, sore throat, red rashes on the skin, tiredness, weakness, night sweats, and swollen or enlarged glands. 

                                                Fig: Common symptoms of AIDS

Diagnosis

AIDS can be diagnosed through two methods as follows:

• ELISA
• Western blot

ELISA

ELISA is abbreviated as ‘enzyme-linked immunosorbent assay’ and is used to detect HIV infection. It is a non isotopic immunoassay. If the result of ELISA is positive, then a western blot test is administered to confirm the infection. 

Samples used for ELISA

The body starts producing antibodies against HIV within 3 - 12 weeks which is why antibodies against HIV can be detected using ELISA as early as 3 weeks into the infection. Body fluids such as blood, saliva or urine are used as samples for the test as these would contain the antibodies. The capsid protein is the antigen that will be detected in ELISA in the case of HIV or AIDS. In the ELISA test, the sample of the patient’s blood is used to test the antibodies. Oral fluid except saliva is collected from the cheeks and gums. A urine sample is also used for ELISA but it is not so sensitive as compared to the blood and oral fluid. 

Principle of ELISA

The presence of HIV in the body can be tested with the help of enzyme linked immunosorbent assay (ELISA). This technique is based on the principle of antigen-antibody reaction and detects the presence of specific antibodies, directed against the virus, in the body fluids but can not detect infected helper T cells or the viral RNA and DNA.

Method of ELISA

ELISA is done in a special plate called a microtiter plate which has multiple wells in it. The patient's serum is then added to the well. The well contains antibodies that can bind against the antigen or the capsid protein. The antigen binds to the primary antibodies present in the well. Excess or unbound antigens are removed with the help of buffer solution. Now the secondary antibodies are added. These antibodies have an enzyme linked to it and it binds to the antigen antibody complex. The unbound antibodies are washed off with the help of buffer solution. The substrate is then added which binds to the enzyme-linked secondary antibody and produces a coloured product. This way, using antigen-antibody interaction, ELISA gives the result. If the individual is HIV positive, then a colour change can be observed in the solution in the well. This is related to the concentration of the protein being estimated. 

                                                      Fig: ELISA

Western blot

This is a very sensitive test mainly used to confirm the positive ELISA test result. A small sample of blood is collected for this test and is used to detect HIV antibodies. The Western blot test separates the proteins in the blood and finds the particular proteins (known as HIV antibodies) that signify an infection with HIV. The combined tests are 99.9% accurate and are used to confirm an ELISA-positive result.

Prevention and care

Since AIDS is still incurable, prevention of HIV is the best course of action. The following measures can be followed:

• Strictly monitoring the blood collected for blood banks is tested for HIV.
• Ensuring the use of only disposable needles and syringes in public and private hospitals and clinics.
• Free distribution of condoms to prevent the transmission of the virus during sexual contact.
• Controlling drug abuse as they run a high chance of infection by reusing needles that might have been contaminated with the virus. 
• Advocating safe sex practices such as use of barriers like condoms to prevent the exchange of body fluids during intercourse.
• Promoting regular check-ups for HIV in susceptible populations such as prostitutes and sex workers.
• Remove social stigma. For example, contrary to the popular belief, HIV does not spread through touch, hugs, regular contact, eating together or normal proximity with patients. Thus making separate eating rooms for AIDS patients is unnecessary as it would play no role in preventing the transmission of the virus.
• Thus patients should not be alienated from friends and family due to fear of spread of the disease through contact or proximity. 
• For the physical and mental well-being of the AIDS patients, it is absolutely necessary that they are not isolated or judged.

HIV and AIDS (Prevention and Control) Act

The HIV and AIDS (Prevention and Control) Act was passed by the Indian government in 2017 and came into effect in 2018. It was overseen by the Ministry of Health and Family Welfare. The following actions come under the scope of the State and Central Governments:

• Preventing the spread of AIDS and HIV.
• Giving ART (Antiretroviral therapy) to patients who are infected.
• Educating people about HIV and AIDS.
• Conducting AIDS and HIV teaching programs.
• Preventing the treatment of infected patients unfairly.
• Offering HIV counselling and treatment at state-run hospitals.

According to the HIV and AIDS (Prevention and Control) Act, no one can administer an HIV test or receive treatment for HIV without the person's agreement. Additionally, the individual will not be forced to reveal his or her HIV status until the court orders it. Any accredited blood bank, a court order, medical research, and epidemiological purposes when the HIV test is anonymous and not intended to detect a person's HIV status are exempt from the requirement for informed consent for an HIV test. Data protection procedures must be implemented by organisations that retain records of information on HIV-positive people. It is also against the law to demand HIV testing as a condition of receiving education, health treatment, or employment. 

In the event of a violation of the law, the person who discloses information about an HIV-positive person or promotes hatred of them faces a fine of one lakh rupees or a prison sentence of three months to two years.

Treatment

Although there is currently no treatment for AIDS, HIV and its consequences can be managed with medicines. The goal of treatment is to lower the amount of HIV in the body, maintain a strong immune system, and lessen any difficulties patients might experience. 

• Antiretroviral therapy(ART) is the most effective HIV treatment. The purpose of this medication combination is to reduce the amount of virus in the body. Antiretroviral drugs reduce the rate of expansion of viruses. By lowering the number of viruses in the body, these medications can keep a person healthy. Different combinations of antiretroviral drugs are used on a daily basis.
• Prevents HIV infection from progressing into AIDS
•  Reduces the risk of transmission

                           Fig: Treatment of AIDS

NACO

NACO is a nodal organisation which is abbreviated as National AIDS Control Organisation. It works under the Ministry of Health and Family Welfare. The organisation works with the state AIDS control societies and other NGOs to closely monitor the AIDS cases in small cities and districts. 

                                           Fig: Logo of NACO

The components of NACO include the following:

• Prevention
• Information, education, and communication
• Testing
• Treatment
• Laboratory services
• Social protection

Prevention

NACO targets high-risk populations, such as female sex workers, injecting drug users, transgenders, and migrants to keep this population HIV free through proper awareness. People having sexually transmitted diseases are more prone to HIV and therefore, NACO supports the services of safe testing and blood transfusing in local clinics.

Information, education, and communication

NACO provides awareness through education and communication which is accomplished through mass media, mid-media, on-ground mobilisation, and interpersonal communication across the country.

Testing

NACO provides free HIV counselling and testing services to detect HIV infection in its early stages. These services are given to pregnant women in order to prevent the transmission of HIV from mother to baby.

Treatment

Free treatment services are provided to the infected people. The test and treat policy is adopted to enhance the uptake of treatment services by HIV-infected people.

Laboratory services

The national AIDS control program ensures the laboratory services to correctly monitor the level of CD4 cells in human fluids.

Social protection

Social protection is attained through partnerships with other departments or ministries in India. This enhances the social awareness about AIDS.

Practice Problems

Q 1. Identify the correct statement regarding HIV, hepatitis B, gonorrhoea, and trichomoniasis.

a. Unlike other diseases, hepatitis B has been totally eradicated
b. In contrast to other illnesses, gonorrhoea is a viral infection
c. HIV is a pathogen while others are diseases
d. Others are not STDs, but trichomoniasis is STD

Answer: Hepatitis B, gonorrhoea, and trichomoniasis are the names of the diseases. Hepatitis B is caused by hepatitis B virus. The bacteria Neisseria gonorrhoeae causes gonorrhoea. The protozoan Trichomonas vaginalis causes trichomoniasis. HIV or Human Immuno deficiency Virus is the pathogen that causes AIDS (Acquired Immuno Deficiency Syndrome). All four are sexually transmitted diseases (STDs). Hence, the correct option is c.

Q 2. Which of the following descriptions of HIV is correct?

Statement I: HIV can be spread through body secretions.
Statement II: By exchanging food with an infected person, HIV can be spread.
Statement III: Infected needles have the potential to spread HIV.
Statement IV: Hugging an HIV-positive individual can spread the disease.

a. 1, 2, 3
b. 1, 4
c. 2, 4
d. 1, 3

Answer: AIDS is caused by HIV or Human Immuno deficiency Virus. Certain body fluids can transmit HIV. It can spread transplacentally or from an infected mother to her unborn child through the placenta. It can pass through sexual contact with an infected person, transfusion of contaminated blood and blood products, and sharing of infected needles like in the case of intravenous drug users. It is vital to remember that HIV only transmits through specific body fluids and cannot be contracted by simple physical contact or touching. Therefore, sharing food or a hug will not cause the virus to spread from an infected person to a healthy person. Hence, the correct option is d.

Q 3. A 20 year old man who had never had any sexual encounter before had a positive HIV test. Which of the following is most likely to be the cause?

a. He would have shaken hands with an HIV-positive person
b. He would have eaten lunch with someone who was HIV positive
c. He would have hugged an HIV-positive person
d. He would have come in contact with an HIV-positive person while sharing a razor or needle

Answer: AIDS is caused by HIV or Human Immuno deficiency Virus. The virus can enter the bloodstream of a person, if they share a razor, toothbrush, tattoo needles, or syringes with someone who is infected with HIV. It is vital to remember that HIV or AIDS only transmits through specific body fluids and cannot be contracted by simple physical contact or touching. Hence, the correct option is d.

Q 4. Identify the STD that does not affect the genital areas.

a. Syphilis
b. AIDS
c. Gonorrhoea
d. Genital warts

Answer: A person's immunity is compromised by AIDS or Acquired Immuno Deficiency Syndrome. The patient's immune system deteriorates to the point where it is unable to defend itself against all illnesses, and as a result, the patient may suffer from multiple infections. Instead of destroying the person's immunity, it has no particular effect on the genitalia. Hence, the correct option is b.

FAQs

Q 1. Do men and women have different HIV symptoms?
Answer: The signs of HIV in men and women are similar. The common fungal illness called candidiasis (caused mainly by Candida albicans), which can appear as a vaginal yeast infection, and bacterial vaginosis (caused by Mobiluncus and Prevotella) are two opportunistics infections that are common to women. It affects their genital tracts.

Q 2. Why should every pregnant woman get An HIV test?
Answer: Pregnant HIV-positive women who receive treatment have a significantly reduced risk of transferring HIV to their unborn child. Hence to avoid complications and stop transfering the virus to the child during pregnancy or delivery they must get an HIV test done. This will also make sure that the Human Immuno deficiency Virus is not transmitted to the health care workers during delivery.

Q 3. Do we get HIV from mosquito bites?
Answer: HIV cannot be physically transmitted by a mosquito. HIV is not able to replicate within the gut of mosquitoes and therefore is broken down. In humans, HIV normally binds to T cells and starts replicating. No T cells can exist inside the gut of mosquitoes and hence the virus has no way of replicating or migrating to the salivary glands of mosquitoes to transmit to other human beings. 

Q 4. Can a pap smear be used to detect the HIV virus?
Answer: Pap smear includes the cells of the cervix and the area around it. The pap smear is used to detect the presence of cancer cells. The presence of HIV is detected mainly through blood and saliva samples.

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