Virology Practice Questions

Q: At present following types of influenza viruses are major circulating strains of clinical significance in the world, except -

Type C virus. ***Type C virus*** - **Influenza C viruses** cause a **mild respiratory illness** and are not associated with epidemics. - They are generally **not considered a major circulating strain of clinical significance** in annual influenza surveillance or vaccine production. *H3N2* - **Influenza A (H3N2)** is a significant **seasonal influenza A subtype** that frequently undergoes **antigenic drift**, leading to new strains each year. - It is a major component of annual influenza vaccines due to its **clinical impact** and **epidemic potential**. *Type B virus* - **Influenza B viruses** regularly circulate in humans and cause **seasonal epidemics**, often affecting children more severely than Type A. - Two main lineages, **B/Yamagata** and **B/Victoria**, are included in quadrivalent influenza vaccines due to their clinical significance. *H1N1* - **Influenza A (H1N1)**, including the strain that caused the **2009 pandemic**, continues to circulate seasonally. - It is a major **influenza A subtype** responsible for significant morbidity and mortality, and is included in annual influenza vaccines.

Q: Subacute sclerosing pan-encephalitis is associated with -

Measles. ***Measles*** - **Subacute sclerosing panencephalitis (SSPE)** is a rare, fatal, progressive neurodegenerative disease caused by a persistent, altered **measles virus** infection of the central nervous system [1]. - The disease typically develops several years after the initial measles infection, characterized by cognitive decline, myoclonus, seizures, and eventual vegetative state [1], [2]. *Rubella* - **Rubella** can cause congenital rubella syndrome if acquired during pregnancy, leading to birth defects including hearing loss, cataracts, and heart defects. - While it can cause encephalitis, it is not associated with **SSPE**. *Mumps* - **Mumps** is primarily known for causing parotitis (swelling of salivary glands) and can lead to complications such as orchitis, oophoritis, and meningitis/encephalitis. - It is not linked to **SSPE**. *Typhoid* - **Typhoid fever** is a bacterial infection caused by *Salmonella Typhi*, transmitted through contaminated food or water, causing fever, abdominal pain, and systemic symptoms. - It is not associated with neurological complications like **SSPE**, which is a viral disease.

Q: Co-infection is essential for disease presentation in:

Delta Hepatitis. ***Delta Hepatitis*** - **Delta hepatitis** (Hepatitis D) is a **defective RNA virus** that requires the presence of Hepatitis B surface antigen for replication and expression. - Therefore, infection with **Hepatitis D** can only occur as a co-infection or superinfection with **Hepatitis B virus (HBV)**. *Hepatitis B* - **Hepatitis B virus (HBV)** can cause acute or chronic hepatitis and does not require co-infection with another distinct virus for its disease presentation. - While it can co-infect with Hepatitis D, it is not essential for HBV itself to cause disease. *Hepatitis A* - **Hepatitis A virus (HAV)** is an RNA virus that causes acute hepatitis and is typically transmitted via the fecal-oral route. - It resolves spontaneously in most cases and does not require co-infection with another virus to manifest disease. *Non A Non B Hepatitis* - The term "Non A Non B Hepatitis" was historically used to describe hepatitis cases that were not caused by Hepatitis A or B. - This category was largely replaced by the identification of **Hepatitis C virus (HCV)**, which does not require co-infection with another virus for its disease presentation.

Q: A 2 month old baby presented with acute icteric viral hepatitis. The mother is a known hepatitis B carrier. Mother's hepatitis B virus serological profile is MOST likely to be:

HBsAg and HBeAg positive. ***HBsAg and HBeAg positive*** - A mother who is **HBsAg and HBeAg positive** has a high viral load and is highly infectious, making vertical transmission to her infant very likely, leading to acute icteric viral hepatitis in the newborn [1]. - **HBeAg positivity** indicates active viral replication, a key factor in efficient perinatal transmission of HBV [1]. *HBsAg and HBe antibody positive* - **HBe antibody positivity** indicates a lower viral load and less active viral replication, suggesting a lower risk of perinatal transmission than if HBeAg were positive [1]. - While the mother is a carrier (HBsAg positive), the presence of HBe antibody usually means the infection is in a less active, potentially chronic persistent phase, with reduced infectivity [1]. *HBsAg positive only* - A mother being **HBsAg positive only** (without HBeAg or antibody information) is insufficient to definitively determine the infectivity status or the likelihood of acute icteric hepatitis in the infant. - **HBsAg positivity** confirms carrier status but doesn't specify the level of viral replication or infectivity as precisely as HBeAg status [1]. *HBV DNA positive* - **HBV DNA positive** indicates the presence of viral genetic material, confirming active infection or replication, but it's a quantitative measure and doesn't replace the serological markers for assessing infectivity in the context of perinatal transmission [1]. - While strongly indicative of active infection, **HBV DNA positive** usually correlates with HBeAg positivity in highly infectious carriers, and HBeAg is the more specific serological marker for this high infectivity state [1].

Q: Which is the most common manifestation of recurrent HSVl infection:

Recurrent herpes labialis. **Recurrent herpes labialis** - **Recurrent herpes labialis**, or **cold sores**, is the most common manifestation of recurrent HSV-1 infection [1]. - It typically presents as vesicles and ulcers on the lips and perioral region due to reactivation of the virus from the **trigeminal ganglia** [1]. *Herpetic whitlow* - **Herpetic whitlow** is an HSV infection of the fingers or toes, often seen in healthcare workers or children, but it is not the most common recurrent manifestation [2]. - It is characterized by painful, vesicular lesions on the digits [2]. *Herpetic keratitis* - **Herpetic keratitis** is a serious ocular infection that can lead to corneal scarring and vision loss, but it is less common than recurrent oral lesions [2]. - It involves the **cornea** and can cause pain, redness, and blurred vision [2]. *Herpos encephalitis* - **Herpes encephalitis** is a rare but severe neurological complication of HSV infection that can cause significant morbidity and mortality. - It involves inflammation of the **brain** and is characterized by fever, headache, altered mental status, and seizures.

Q: Which of the following viral infections is transmitted by tick?

Kyasanur forest disease (KFD). ***Kyasanur forest disease (KFD)*** - KFD is a **viral hemorrhagic fever** caused by the Kyasanur Forest disease virus, a member of the *Flaviviridae* family. - It is primarily transmitted to humans through the bite of infected **ticks**, especially *Haemaphysalis spinigera*. *Ehrlichiosis* - Ehrlichiosis is a **bacterial infection** caused by *Ehrlichia* species, not a viral infection. - It is transmitted by **ticks**, primarily the **lone star tick** (*Amblyomma americanum*). *Lyme disease* - Lyme disease is a **bacterial infection** caused by *Borrelia burgdorferi*, not a viral infection. - It is transmitted by **ticks**, notably the **black-legged tick** (*Ixodes scapularis*). *Rocky Mountain spotted fever* - Rocky Mountain spotted fever (RMSF) is a **bacterial infection** caused by *Rickettsia rickettsii*, not a viral infection. - It is transmitted by **ticks**, such as the **American dog tick**, **Rocky Mountain wood tick**, and **brown dog tick**.

Q: What is the incubation period of Hepatitis B virus?

30-180 days. ***30-180 days*** - The incubation period for **Hepatitis B virus (HBV)** is typically long, ranging from **30 to 180 days**, reflecting the time from exposure to symptom onset or detection of viral markers. - This broad range allows for the virus to replicate and reach a detectable level in the body before clinical signs of **acute hepatitis** manifest. *8-10 days* - An incubation period of **8-10 days** is far too short for Hepatitis B virus. - Such a short period is more characteristic of rapidly acting viral or bacterial infections. *1 year* - A 1-year incubation period is **too long** for typical presentation of acute Hepatitis B. - While chronic infection can persist for years, the initial incubation before symptom onset is much shorter. *2 years* - A 2-year incubation period is also **excessively long** for the acute phase of Hepatitis B infection. - This timeframe is not consistent with the known viral kinetics and immune response associated with HBV.

Q: Juvenile papillomatosis is caused by -

HPV. ***HPV*** - **Juvenile papillomatosis**, often referred to as **recurrent respiratory papillomatosis (RRP)** in children, is primarily caused by **Human Papillomavirus (HPV)**. - Specifically, **HPV types 6 and 11** are responsible for the vast majority of cases, leading to the formation of benign, wart-like growths in the larynx and other parts of the respiratory tract. *Adenovirus* - **Adenovirus** can cause a range of respiratory illnesses, including pharyngitis, bronchitis, and pneumonia. - However, it is not associated with the development of **papillomas** or respiratory papillomatosis. *Parainfluenza virus* - **Parainfluenza viruses** are a common cause of respiratory tract infections, particularly in young children, leading to conditions like **croup**, bronchitis, and bronchiolitis. - They do not cause **papilloma formation** in the respiratory tract. *Influenza virus* - The **influenza virus** is responsible for seasonal epidemics of the flu, characterized by fever, cough, body aches, and respiratory symptoms. - It does not cause the proliferation of **papillomatous growths** in the respiratory system.

Q: Rubella is caused by

Togavirus. ***Correct Answer: Togavirus*** - Rubella virus is classified under the genus *Rubivirus* within the family **Togaviridae** - Togaviruses are **enveloped, positive-sense, single-stranded RNA viruses** - Rubella causes German measles, characterized by mild fever and maculopapular rash - Important for congenital rubella syndrome when infection occurs during pregnancy *Incorrect: Paramyxovirus* - This family includes viruses like **measles (rubeola)** and **mumps** - Paramyxoviruses are enveloped, negative-sense, single-stranded RNA viruses - Different structural and genetic characteristics from rubella virus *Incorrect: Orthomyxovirus* - This family primarily consists of **influenza viruses** (types A, B, and C) - Orthomyxoviruses are enveloped, **negative-sense, segmented** RNA viruses - The segmented genome distinguishes them from rubella virus *Incorrect: Flavivirus* - This family includes **dengue virus**, **yellow fever virus**, and **Zika virus** - While flaviviruses are also enveloped, positive-sense, single-stranded RNA viruses, they belong to the family *Flaviviridae*, not Togaviridae - Different envelope proteins and replication strategies distinguish them from rubella virus

Q: A neonate was found to have cataract, deafness and cardiac defects. Which group of viruses was the mother infected with?

Togaviridae family (includes Rubella virus). ***Togaviridae family (includes Rubella virus)*** - The classic triad of **congenital rubella syndrome (CRS)** includes **cataracts**, **deafness**, and **cardiac defects** (e.g., patent ductus arteriosus, pulmonary artery stenosis). - Rubella virus is a member of the **Togaviridae family** and causes significant fetal damage if the mother is infected during the first trimester. *Flaviviridae family (includes Zika virus)* - While congenital Zika syndrome can cause severe birth defects, it is primarily associated with **microcephaly**, intracranial calcifications, and ocular abnormalities, not typically the classic rubella triad. - **Deafness** and **linear cataracts** are not characteristic features of congenital Zika infection. *Bunyaviridae family (includes Rift Valley fever virus)* - Rift Valley fever virus is primarily transmitted by mosquitoes and causes **febrile illness** in humans and livestock, with potential for **hemorrhagic fever** or **encephalitis**. - It is not known to cause congenital abnormalities resembling cataracts, deafness, and cardiac defects in neonates. *Arenaviridae family (includes Lassa fever virus)* - Lassa fever virus causes a severe **hemorrhagic fever** in humans, primarily through contact with infected rodents or person-to-person transmission. - It is not associated with congenital malformations such as cataracts, deafness, and cardiac defects.

Question 1

At present following types of influenza viruses are major circulating strains of clinical significance in the world, except -

Accepted Answer

Type C virus

Answer

H3N2

Answer

Type B virus

Answer

H1N1

Question 2

Subacute sclerosing pan-encephalitis is associated with -

Accepted Answer

Measles

Answer

Rubella

Answer

Mumps

Answer

Typhoid

Question 3

Co-infection is essential for disease presentation in:

Accepted Answer

Delta Hepatitis

Answer

Hepatitis B

Answer

Hepatitis A

Answer

Non A Non B Hepatitis

Question 4

A 2 month old baby presented with acute icteric viral hepatitis. The mother is a known hepatitis B carrier. Mother's hepatitis B virus serological profile is MOST likely to be:

Accepted Answer

HBsAg and HBeAg positive

Answer

HBsAg and HBe antibody positive

Answer

HBsAg positive only

Answer

HBV DNA positive

Question 5

Which is the most common manifestation of recurrent HSVl infection:

Accepted Answer

Recurrent herpes labialis

Answer

Herpetic whitlow

Answer

Herpetic keratitis

Answer

Herpes encephalitis

Question 6

Which of the following viral infections is transmitted by tick?

Accepted Answer

Kyasanur forest disease (KFD)

Answer

Ehrlichiosis

Answer

Lyme disease

Answer

Rocky Mountain spotted fever

Question 7

What is the incubation period of Hepatitis B virus?

Accepted Answer

30-180 days

Answer

8-10 days

Answer

1 year

Answer

2 years

Question 8

Juvenile papillomatosis is caused by -

Accepted Answer

HPV

Answer

Adenovirus

Answer

Parainfluenza virus

Answer

Influenza virus

Question 9

Rubella is caused by

Accepted Answer

Togavirus

Answer

Paramyxovirus

Answer

Orthomyxovirus

Answer

Flavivirus

Question 10

A neonate was found to have cataract, deafness and cardiac defects. Which group of viruses was the mother infected with?

Accepted Answer

Togaviridae family (includes Rubella virus)

Answer

Flaviviridae family (includes Zika virus)

Answer

Bunyaviridae family (includes Rift Valley fever virus)

Answer

Arenaviridae family (includes Lassa fever virus)

Virology — MCQs

Virology — MCQs

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