5_PICO_Flashcards

Question 1

What is the genome structure of Picornavirus?

Answer 1

Picornavirus has a small linear +ssRNA genome, which is equivalent to mRNA. It is icosahedral and non-enveloped.

Question 2

What are examples of Picornavirus?

Answer 2

Examples include Coxsackie, Echo, Polio, Rhinovirus, Entero71, and Entero72.

Question 3

How is Picornavirus transmitted?

Answer 3

Transmitted via the fecal-oral route; however, the main infection site is not the GI tract, except Rhinovirus.

Question 4

What is the receptor used by Picornavirus for attachment?

Answer 4

The receptor is ICAM (Intercellular Adhesion Molecule), which helps with virus attachment.

Question 5

Where does Picornavirus replicate?

Answer 5

Replication occurs in the cytoplasm and is usually cytolytic. It initially replicates in the oropharynx, tonsils, and Peyer’s patches.

Question 6

Define primary and secondary viremia in Picornavirus.

Answer 6

Primary viremia refers to the initial spread of the virus in the bloodstream. Secondary viremia occurs when the virus targets specific tissues and spreads further.

Question 7

What tissues are targeted by Poliovirus?

Answer 7

Poliovirus targets motor neurons in the CNS, causing motor dysfunction or paralysis.

Question 8

How many serotypes are there in Coxsackie virus?

Answer 8

Coxsackie virus has 30 serotypes.

Question 9

What is the incubation period of Coxsackie virus?

Answer 9

The incubation period is 1-7 days.

Question 10

What organs are targeted by Coxsackie B virus?

Answer 10

Coxsackie B virus targets the heart (myocarditis, pericarditis), lungs, and CNS (aseptic meningitis).

Question 11

List clinical features of Coxsackie A virus.

Answer 11

Coxsackie A causes vesicular lesions (herpangina, hand-foot-mouth disease by A5, A16), rhino-like symptoms (A21, A24), and acute hemorrhagic conjunctivitis (A24).

Question 12

What are the clinical manifestations of Coxsackie B virus?

Answer 12

Coxsackie B causes myocarditis and pericarditis (leading to heart failure, especially in older children), pleurodynia (Bornholm disease, or ‘devil’s grip’), and aseptic meningitis.

Question 13

What does ‘Echoviruses’ stand for?

Answer 13

‘Enteric cytopathic human orphan’ (Echoviruses).

Question 14

What clinical manifestation is associated with Echoviruses?

Answer 14

Echoviruses can cause aseptic meningitis with or without a rash.

Question 15

How many serotypes does Poliovirus have?

Answer 15

Poliovirus has 3 serotypes.

Question 16

Describe the transmission and target tissue of Poliovirus.

Answer 16

Poliovirus is transmitted via the fecal-oral route, usually in summer and autumn. It targets the skeletal muscle and motor system, including the anterior horn cells (AHC) and brainstem.

Question 17

What is the incubation period of Poliovirus?

Answer 17

The incubation period is 5-20 days.

Question 18

List the clinical presentations of Poliovirus.

Answer 18

1. Asymptomatic (90%): Limited to the oropharynx and GIT.
2. Abortive (5%): Features fever, headache, malaise, sore throat, and vomiting (‘minor illness’).
3. Aseptic meningitis (2%): Presents with viral meningitis symptoms and minor illness.
4. Paralytic polio (2%): Symptoms include minor illness followed by paralysis due to AHC and motor cortex involvement.

Question 19

Describe the changes in CSF during Poliovirus infection.

Answer 19

Increased lymphocytes, increased protein, and normal glucose levels in the CSF.

Question 20

What vaccines are available for Poliovirus?

Answer 20

1. Salk ‘IPV’: Inactivated polio vaccine.
2. Sabin ‘OPV’: Live attenuated polio vaccine.
   Both provide lifelong immunity covering all 3 serotypes.

Question 21

How many serotypes does Rhinovirus have?

Answer 21

Rhinovirus has 100 serotypes.

Question 22

How is Rhinovirus transmitted, and what are its growth conditions?

Answer 22

Transmitted by direct contact with respiratory secretions. It shows optimal growth at 33°C.

Question 23

What evolutionary mechanism contributes to Rhinovirus’s antigenic variation?

Answer 23

Rhinovirus exhibits antigenic drift, leading to frequent variations.

Question 24

What receptor does Rhinovirus enhance to facilitate viral entry?

Answer 24

Rhinovirus enhances the ICAM receptor, facilitating more viral entry.

Question 25

What are the common clinical symptoms of Rhinovirus infection?

Answer 25

Low-grade fever and runny nose are common symptoms.

Question 26

What is more important in Rhinovirus immunity: antibodies or cell-mediated immunity?

Answer 26

Antibodies (Ab) are more important than cell-mediated immunity (CMI) in Rhinovirus infection.

Question 27

What are the treatment and prevention strategies for Rhinovirus?

Answer 27

Treatment involves symptom relief (e.g., nasal vasoconstrictors). Pleconaril is not commonly used because the infection is self-limiting. Prevention includes hand washing and disinfectants.