Clinically Important RNA Viruses Overview

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Questions and Answers

Which virus is NOT classified as a Picornavirus?

Poliovirus

Echovirus

Rhinovirus

Hepatitis C virus (correct)

What is the primary clinical symptom associated with Rotavirus infection?

Fever

Cough and cold

Diarrhea (correct)

Aseptic meningitis

Which of the following RNA viruses is known to have a helical capsid structure?

Coxsackievirus

Ebola virus (correct)

Hepatitis E virus

Norovirus

Which clinical symptom is associated with Dengue virus infection?

Joint aches Signup and view all the answers

Which of the following viruses requires Hepatitis B virus for infection?

Hepatitis D virus Signup and view all the answers

What distinguishes rhinoviruses from other enteroviruses?

They have over 100 serotypes that cause common colds. Signup and view all the answers

Which of the following is NOT a characteristic of flaviviruses?

They are generally transmitted through respiratory droplets. Signup and view all the answers

What is the main human pathogen associated with caliciviruses?

Norwalk virus Signup and view all the answers

What kind of RNA do reoviruses contain?

Double-stranded linear RNA Signup and view all the answers

Which of the following statements about hepeviruses is correct?

The major human pathogen is hepatitis E virus. Signup and view all the answers

What is the structural characteristic of Togaviruses?

Icosahedral capsid with single-stranded RNA Signup and view all the answers

Which disease is NOT associated with Coronaviruses?

Rubella Signup and view all the answers

What distinguishes Retroviruses from other RNA viruses?

Integration of DNA into cellular DNA Signup and view all the answers

Which is NOT a characteristic of Orthomyxoviruses?

They contain a non-enveloped structure Signup and view all the answers

What is the size range of the genome in Coronaviruses?

27–32 kb Signup and view all the answers

Which of the following correctly categorizes Retroviruses?

They have two identical strands of single-stranded RNA Signup and view all the answers

What type of RNA do Orthomyxoviruses contain?

Single-stranded, negative-sense Signup and view all the answers

Which group is NOT part of the Togavirus family?

HIV Signup and view all the answers

What is the primary function of reverse transcriptase in Retroviruses?

To convert RNA into DNA Signup and view all the answers

Study Notes

Clinically Important RNA Viruses

RNA viruses are classified into various families based on envelope presence, capsid symmetry, RNA structure, and clinical significance.
Key RNA virus families include Reoviruses, Picornaviruses, Caliciviruses, Flaviviruses, Togaviruses, Retroviruses, Coronaviruses, Orthomyxoviruses, Paramyxoviruses, Rhabdoviruses, Filoviruses, Arenaviruses, and Bunyaviruses.

Virus Families Overview

Reoviruses: Non-enveloped, icosahedral, double-stranded RNA. Notable for causing diarrhea in infants (Rotavirus).
Picornaviruses: Non-enveloped, linear single-stranded RNA. Includes poliovirus (aseptic meningitis) and rhinoviruses (common cold).
Caliciviruses: Non-enveloped, single-stranded RNA. Major pathogen is Norovirus, linked to gastroenteritis.
Flaviviruses: Enveloped, single-stranded RNA. Key viruses include Hepatitis C, Yellow fever, and Zika virus, often transmitted by arthropods.
Togaviruses: Enveloped, single-stranded RNA. Notable for Rubella virus and encephalitis viruses.
Retroviruses: Enveloped, single-stranded RNA that reverse transcribes into DNA. Key virus is HIV, responsible for AIDS.
Coronaviruses: Enveloped, single-stranded RNA. Include mild cold viruses and severe pathogens like SARS-CoV-2, leading to respiratory disease.
Orthomyxoviruses: Enveloped, segmented negative-sense RNA. Includes influenza viruses that can undergo genetic reassortment.
Paramyxoviruses: Enveloped, non-segmented negative-sense RNA. Includes pathogens like Measles, Mumps, and Respiratory Syncytial Virus (RSV).
Rhabdoviruses: Enveloped, negative-sense RNA. Key pathogen is Rabies virus, characterized by bullet-shaped morphology.
Filoviruses: Enveloped, negative-sense RNA. Include Ebola and Marburg viruses, requiring high containment for study.
Arenaviruses: Pleomorphic, enveloped viruses with ambisense RNA. Include Lymphocytic choriomeningitis virus and Lassa virus.

Replication and Maturation Strategies

RNA viruses can be categorized based on their genomic RNA structure and replication strategies, affecting how they synthesize proteins and mature.
Positive-strand viruses: Include Picornaviridae, Togaviridae, Retroviridae. Genomic RNA is infectious and acts as mRNA.
Negative-strand viruses: Include Orthomyxoviridae, Paramyxoviridae, Rhabdoviridae. Require viral enzymes to transcribe RNA.
Replication cycle: Varies among families, affecting total time for maturation and site of genome replication (cytoplasm or nucleus). Example: Picornaviridae (6-8 hours) versus Orthomyxoviridae (15-30 hours).

Key Clinical Symptoms Associated with Viruses

Rotavirus: Diarrhea in infants.
Poliovirus: Aseptic meningitis, flaccid paralysis.
Rhinovirus: Common cold.
Hepatitis A & E: Hepatitis.
Norovirus: Gastroenteritis.
Yellow fever: Fever, nausea, jaundice.
HIV: AIDS.
Influenza virus: Flu and associated complications.
Measles: Cough, cold, conjunctivitis, rash.
Rabies virus: Fever, agitation, hydrophobia.

Conclusion

Understanding the classification, replication mechanisms, and clinical implications of RNA viruses is crucial for diagnostics and treatment of viral infections.

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Description

This quiz explores the various families of clinically important RNA viruses, detailing their characteristics and clinical significance. Topics include Reoviruses, Picornaviruses, Caliciviruses, and more. Test your knowledge on the structure, transmission, and diseases caused by these viruses.