HIV and Retroviruses — MCQs
WHO AIDS defining illnesses are all EXCEPT:
A nurse got accidental prick from the HIV infected needle. Which of the following statements is false regarding the management of this nurse?
Which is not included in AIDS related complex?
Macrophage tropic strains of HIV use which co-receptor?
Which of the following is not considered an opportunistic infection in AIDS?
Which of the following is the envelope glycoprotein of HIV that binds to CD4 receptors for cell entry?
Screening test for HIV infection in a patient prior to the development of antibodies (in window period):
Best method to diagnose HIV in an infant?
What is the most common oncogenic RNA virus?
Which of the following statements about p24 is false?
HIV and Retroviruses Indian Medical PG Practice Questions and MCQs
Question 1: WHO AIDS defining illnesses are all EXCEPT:
- A. Persistent generalized lymphadenopathy (Correct Answer)
- B. P. carinii pneumonia
- C. CMV retinitis
- D. Oropharyngeal candidiasis
Explanation: ***Persistent generalized lymphadenopathy*** - While associated with HIV infection, **persistent generalized lymphadenopathy** itself is not classified as an **AIDS-defining illness** by the WHO or CDC, but rather a common manifestation of chronic HIV infection (Stage 1 or 2) [1]. - AIDS-defining illnesses are typically severe opportunistic infections or cancers that occur when the immune system is severely compromised (CD4 count below 200 cells/µL). *P. carinii pneumonia* - **P. carinii pneumonia** (now known as **Pneumocystis jirovecii pneumonia** or **PJP**) is a classic and common **AIDS-defining opportunistic infection**. - Its presence indicates severe immunosuppression, often with CD4 counts below 200 cells/µL. *CMV retinitis* - **Cytomegalovirus (CMV) retinitis** is a severe opportunistic infection, particularly of the eye, that is recognized as an **AIDS-defining illness**. - It signifies profound immunodeficiency, typically with CD4 counts below 50 cells/µL. *Oropharyngeal candidiasis* - While common in HIV-infected individuals, **oropharyngeal candidiasis** (thrush) alone is generally not considered an **AIDS-defining illness** [1]. - It is classified as an HIV Stage 2 condition, indicating moderate immune compromise rather than severe, AIDS-defining immunosuppression [1].
Question 2: A nurse got accidental prick from the HIV infected needle. Which of the following statements is false regarding the management of this nurse?
- A. Follow up viral markers of health care personnel should be measured at 6 weeks
- B. Zidovudine is used as monotherapy for post-exposure prophylaxis (Correct Answer)
- C. Baseline viral markers of health care personnel should be done at the time of presentation
- D. Washing hands with soap and water is advised
Explanation: **Zidovudine is used as monotherapy for post-exposure prophylaxis** - **Monotherapy** with zidovudine is **insufficient** for effective **HIV post-exposure prophylaxis (PEP)** due to the high risk of treatment failure and development of drug resistance. - **Current guidelines** recommend a **multi-drug regimen**, typically involving three antiretroviral drugs, for PEP to maximize efficacy against HIV transmission. *Follow up viral markers of health care personnel should be measured at 6 weeks* - **Follow-up viral markers** for HIV, such as **HIV RNA PCR** and **antibody tests**, are routinely measured at specific intervals (e.g., 6 weeks, 3 months, 6 months) to monitor for seroconversion [1]. - This allows for **early detection of HIV infection** if PEP fails, enabling prompt initiation of treatment. *Baseline viral markers of health care personnel should be done at the time of presentation* - Establishing **baseline HIV status** of the healthcare worker at the time of exposure is crucial to differentiate pre-existing infection from a new infection acquired from the needle stick [1]. - This information helps in **interpreting subsequent test results** and guiding further management. *Washing hands with soap and water is advised* - **Immediate washing** of the exposed area with **soap and water** is an important first step in managing a needle stick injury [1]. - This **reduces the viral load** at the site of exposure, minimizing the risk of transmission, although it does not eliminate the need for PEP.
Question 3: Which is not included in AIDS related complex?
- A. Recurrent genital candidiasis
- B. Generalised lymphadenopathy
- C. Chronic diarrhea
- D. Ectopic pregnancy (Correct Answer)
Explanation: ***Ectopic pregnancy*** - **Ectopic pregnancy** is a gynecological condition related to reproductive health and is **not a direct manifestation** of HIV infection or one of the opportunistic infections/conditions characteristic of AIDS-related complex. - While HIV can affect overall health during pregnancy, an ectopic pregnancy itself is a different medical issue. *Recurrent genital candidiasis* - **Recurrent genital candidiasis** can be a sign of **diminished immune function** in HIV-positive women [1]. - It is often considered an AIDS-defining condition or a common opportunistic infection seen in the progression of HIV to AIDS-related complex [1]. *Generalised lymphadenopathy* - **Generalized lymphadenopathy**, specifically **persistent generalized lymphadenopathy (PGL)**, is a common early manifestation of HIV infection [1]. - It reflects ongoing immune activation and is part of the spectrum of conditions included in AIDS-related complex [1]. *Chronic diarrhea* - **Chronic diarrhea** (lasting more than one month) is a frequent and significant symptom in individuals with HIV infection, particularly as the disease progresses [1]. - It can be caused by various opportunistic infections or directly by HIV, and is a component of AIDS-related complex or AIDS-defining illness [1].
Question 4: Macrophage tropic strains of HIV use which co-receptor?
- A. CCR5 (Correct Answer)
- B. CXCR4
- C. CCR3
- D. CCR2
Explanation: ***CCR5*** - **Macrophage-tropic** HIV strains, also known as **R5 strains**, primarily use the **CCR5 co-receptor** to enter target cells. - These strains are typically involved in the **initial infection** and transmission of HIV. - CCR5-tropic viruses are usually the **predominant strains transmitted** during sexual transmission. *CXCR4* - **T-cell-tropic** HIV strains, or **X4 strains**, preferentially utilize the **CXCR4 co-receptor** for cell entry. - These strains are associated with a **more rapid decline in CD4+ T-cell counts** during later stages of HIV infection. - Emergence of X4 strains is linked to **disease progression**. *CCR3* - While a chemokine receptor, **CCR3** is not a primary co-receptor used by common HIV strains for entry into macrophages or T cells. - CCR3 is primarily involved in **eosinophil chemotaxis** and allergic responses. *CCR2* - **CCR2** is another chemokine receptor but is **not a major co-receptor** for HIV entry. - While some laboratory-adapted strains may show minor usage, it is not clinically significant for macrophage-tropic HIV strains.
Question 5: Which of the following is not considered an opportunistic infection in AIDS?
- A. Candidiasis
- B. Kaposi's sarcoma
- C. Rubella (Correct Answer)
- D. Cytomegalovirus infection
Explanation: ***Rubella*** - Rubella, or **German measles**, is a relatively mild viral infection that typically affects children and is not considered an **opportunistic infection** in immunocompromised individuals like those with AIDS [1]. - While it can cause congenital rubella syndrome in infants whose mothers are infected during pregnancy, it does not disproportionately affect or cause severe disease in AIDS patients due to their compromised immunity [1]. *Candidiasis* - **Oropharyngeal** and **esophageal candidiasis** are common opportunistic infections in AIDS patients, often indicating significant immune suppression [2,3]. - The fungus *Candida albicans* can proliferate unchecked when the **CD4 count** is low [2]. *Kaposi's sarcoma* - This is a **cancer** caused by the **human herpesvirus 8 (HHV-8)**, which is a classic AIDS-defining illness [3]. - Its presence indicates severe immunodeficiency and was a hallmark of the early AIDS epidemic [3]. *Cytomegalovirus infection* - **Cytomegalovirus (CMV)** can cause severe and widespread disease in AIDS patients, including **retinitis**, **colitis**, and **encephalitis** [2]. - It becomes a significant risk when the **CD4 count** drops below 100 cells/mm³ [2].
Question 6: Which of the following is the envelope glycoprotein of HIV that binds to CD4 receptors for cell entry?
- A. Gp73
- B. P24
- C. GP120 (Correct Answer)
- D. Gp5
Explanation: ***GP120*** - **GP120** is the crucial **envelope glycoprotein** found on the surface of the **Human Immunodeficiency Virus (HIV)**. - It is essential for **viral entry** into host cells by binding to the **CD4 receptor** and a **co-receptor (CCR5 or CXCR4)** on T-helper cells. - This makes it a primary target for **neutralizing antibodies** and **vaccine development**. *Gp73* - **Gp73** is a **Golgi protein** that has been studied as a biomarker for **liver fibrosis** and **hepatocellular carcinoma**. - It is **not associated with HIV** structure or function. *P24* - **P24** is a **capsid protein** of HIV that forms the conical core surrounding the viral RNA. - While it is an important **HIV structural protein** used in diagnostic testing, it is **not an envelope glycoprotein**. - P24 is located **inside the virion**, not on the surface, and does not participate in CD4 receptor binding. *Gp5* - **Gp5** refers to a **glycoprotein** associated with other viruses, such as certain **herpesviruses** like **cytomegalovirus (CMV)**. - It is **not a protein of HIV**.
Question 7: Screening test for HIV infection in a patient prior to the development of antibodies (in window period):
- A. Western blot
- B. p24 antigen (Correct Answer)
- C. ELISA
- D. All of the options
Explanation: ***p24 antigen*** - The **p24 antigen** test detects a structural protein of HIV, which becomes detectable before the development of antibodies (during the **window period**). - This test is crucial for early detection of HIV infection, especially when antibody tests might still be negative due to the time lag in immune response. *Western blot* - The **Western blot** is a confirmatory test for HIV, detecting specific antibodies to various HIV proteins. - It becomes positive only after the development of antibodies, making it unsuitable for detecting infection during the **window period**. *ELISA* - **ELISA** (Enzyme-Linked Immunosorbent Assay) is a common screening test for HIV, primarily detecting **HIV antibodies**. - Like Western blot, it relies on antibody presence and thus will be negative during the **window period**. *All of the options* - This option is incorrect because both **Western blot** and **ELISA** detect antibodies, making them unsuitable for screening during the **window period**. - Only the **p24 antigen** test can detect HIV infection before antibody seroconversion.
Question 8: Best method to diagnose HIV in an infant?
- A. ELISA
- B. PCR (Correct Answer)
- C. Western blot
- D. All of the options
Explanation: ***PCR*** - **Polymerase Chain Reaction (PCR)** detects **HIV nucleic acids** (DNA or RNA) directly, which is crucial for infants because maternal antibodies can persist for up to 18 months, interfering with antibody-based tests. - PCR allows for early diagnosis, often within the first few weeks or months of life, facilitating timely intervention. *ELISA* - **Enzyme-linked immunosorbent assay (ELISA)** detects HIV antibodies. - In infants, ELISA can be misleading due to the presence of **maternal HIV antibodies** transferred across the placenta, making it unreliable for diagnosing active infection. *Western blot* - **Western blot** is used to confirm positive ELISA results in adults by detecting specific HIV proteins. - Like ELISA, it relies on the detection of **antibodies** and is therefore not reliable in infants due to maternally transmitted antibodies. *All of the options* - This option is incorrect because **ELISA** and **Western blot** are antibody-based tests that are unreliable in infants due to the presence of **maternal antibodies**. - Only **PCR** directly detects the virus itself, making it the preferred diagnostic method in this age group.
Question 9: What is the most common oncogenic RNA virus?
- A. Retrovirus (Correct Answer)
- B. Picornavirus
- C. Orthomyxovirus
- D. Paramyxovirus
Explanation: ***Retrovirus*** - **Retroviruses** integrate their **RNA genome** into the host cell's DNA, a process mediated by **reverse transcriptase**, which can lead to **oncogenesis** by altering host gene expression or introducing oncogenes. - The **Human T-cell Lymphotropic Virus (HTLV-1)** is a well-known oncogenic retrovirus linked to **Adult T-cell Leukemia/Lymphoma**. *Picornavirus* - **Picornaviruses** are a family of **non-enveloped RNA viruses** that cause diseases like polio and the common cold. - They replicate in the cytoplasm and are typically associated with **acute infections**, not **oncogenesis**. *Orthomyxovirus* - **Orthomyxoviruses**, including the **influenza virus**, are **enveloped RNA viruses** that primarily infect the respiratory tract. - They are known for causing **acute respiratory illnesses** and are not associated with **oncogenesis**. *Paramyxovirus* - **Paramyxoviruses** are a family of **enveloped RNA viruses** that cause diseases such as measles and mumps. - They replicate in the cytoplasm and are associated with **acute respiratory** or **systemic infections**, not **cancer development**.
Question 10: Which of the following statements about p24 is false?
- A. Cannot be detected after seroconversion (Correct Answer)
- B. Cannot be seen in the first week
- C. All of the above
- D. Can be detected after 3 weeks of infection
Explanation: ***Cannot be detected after seroconversion*** - This statement is **FALSE** and is the correct answer to this question. - **p24 antigen levels do decrease** after seroconversion due to immune complex formation with antibodies, but p24 can still be detected using modern assays. - In **advanced HIV disease** with declining CD4 counts, p24 antigen often becomes detectable again due to high viral loads. - Fourth-generation HIV tests detect both antibodies and p24 antigen throughout the infection course. *Cannot be seen in the first week* - This statement is **TRUE** (not the answer). - p24 antigen typically appears around **10-14 days** (1.5-2 weeks) after infection, which is after the first week (days 1-7). - The eclipse period (first 7-10 days) precedes p24 detection. *Can be detected after 3 weeks of infection* - This statement is **TRUE** (not the answer). - p24 antigen is consistently detectable at 3 weeks post-infection during the acute viremic phase. - Peak p24 levels occur around **2-4 weeks** after infection. *All of the above* - This is a distractor option and is incorrect since only one statement is false.
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