Questions and Answers
Which virus is associated with cold sores and fever blisters?
What disease is caused by Human Herpesvirus 6?
Roseola infantum
All RNA viruses replicate in the cytoplasm.
False
The mode of transmission for Hepatitis A is through _____ transmission.
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What disease is caused by the Rota Virus?
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What is the disease caused by the Hepatitis C Virus?
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What is the clinical finding associated with Kaposi Sarcoma?
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Match the following viruses with their diseases:
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Human Hepatitis E Virus (HEV) transmits through respiratory droplets.
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Who is credited as the discoverer of viruses?
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What type of genetic material can viruses have?
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Viruses can be treated with medications and antiretroviral therapies.
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Which of the following diseases is caused by the Tobacco Mosaic Virus?
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A virus that causes Yellow Fever is discovered by _____
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What is a virion?
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What type of particles are prions?
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Match the following viral diseases with their causative viruses:
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All DNA viruses replicate in the nucleus.
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Koilocytes are a distinct histopathological cytopathic effect of _____ infections.
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Study Notes
Introduction to Virology
- Virology studies viruses, including their structure, classification, evolution, interactions with hosts, diseases caused, and isolation techniques.
- Key figures include Louis Pasteur, who pioneered rabies vaccines; Adolf Mayer, who linked Tobacco Mosaic Disease to contagion; and Walter Reed, who identified the Yellow Fever virus.
General Characteristics of Viruses
- Viruses are acellular, infectious agents with nucleic acids (RNA or DNA) encased in protein capsids.
- They are obligate intracellular parasites, require electron microscopy for visualization, and provide minimal treatment options.
- Viral infections can increase cancer risk.
Defining Life and Virions
- Viruses lack respiratory functions, irritability, mobility, growth, and energy production.
- A virion is a complete, infective virus form outside a host cell.
Historical Development of Virology
- Dmitry Ivanowsky, known as the "Father of Virology," discovered viruses in 1892.
- Martinus Beijerinck contributed to virology by defining the term "contagium vivum fluidum."
- Prions are misfolded proteins causing neurodegenerative diseases.
Viral Structure
- Capsids, composed of capsomers, can be helical, icosahedral, or complex.
- Viral genomes consist of either DNA or RNA nucleotides.
Viral Culture Methods
- Animal inoculation is used primarily for Coxsackievirus culture.
- Embryonated egg culture is recommended for Influenza viruses.
- Cell culture is standard in laboratories, with primary, finite, and continuous cultures.
Viral Cytopathic Effects
- Virally infected cells exhibit distinct visible changes; DNA viruses show intranuclear effects, while RNA viruses show intracytoplasmic effects.
DNA Viruses Overview
- Most DNA viruses are double-stranded (dsDNA) except Parvoviridae and are mostly naked except for major families.
- Most replicate in the nucleus, except for Poxviridae.
Notable DNA Virus Families
- Parvoviridae: Smallest viruses, single-stranded DNA, causes Erythema infectiosum.
- Papillomaviridae (HPV): Associated with cervical cancer; causes common and genital warts.
- Adenoviridae: Creates epidemic keratoconjunctivitis and pharyngoconjunctival fever.
- Poxviridae: Includes Smallpox, once eradicated but with potential reemergence due to vaccination resurgence.
Other Viral Diseases and Clinical Findings
- Varicella-Zoster Virus: Causes Chickenpox in childhood; can reactivate to cause Shingles.
- Epstein-Barr Virus (EBV): Causes infectious mononucleosis, associated with Burkitt’s Lymphoma.
- Hepatitis B Virus: Increases the risk of hepatocellular carcinoma, primarily transmitted through blood and other fluids.
Summary of Important Viruses
- Tobacco Mosaic Virus: Historic agent in virology studies.
- Vaccinia Virus: Utilized in Smallpox vaccines due to its cross-reactivity.
- Molluscum contagiosum: Creates benign epidermal nodule with specific histopathological findings.### Acute and Chronic Viral Infections
- Heterophile positive indicates the presence of certain antibodies associated with infectious mononucleosis.
- Clinical findings of viral hepatitis include jaundice and potential progression to hepatic cirrhosis.
- Cytomegalovirus (CMV) can cause infectious mononucleosis-like symptoms and congenital disorders.
- Herpes Simplex Virus (HSV) is divided into two types:
- HSV-1 typically causes cold sores and facial blisters.
- HSV-2 is associated with genital herpes.
Human Herpesviruses
- Human Herpesvirus 6 (HHV-6) causes roseola infantum, also known as the sixth disease.
- Human Herpesvirus 7 (HHV-7) is linked to roseola.
- Human Herpesvirus 8 (HHV-8) is associated with Kaposi Sarcoma, particularly in AIDS patients, characterized as a vascular tumor.
RNA Viruses
- All RNA viruses are single-stranded (ssRNA) except for Reoviridae.
- Most RNA viruses replicate in the cytoplasm, with exceptions such as Influenza (Orthomyxoviridae) and Retroviridae.
Picornaviridae Family
- Polio Virus, with vaccines developed by Sabin and Salk, causes paralytic poliomyelitis.
- Coxsackie Virus A leads to pleurodynia and myocarditis.
- Rhinovirus is acid-labile and causes common colds.
Togaviridae Family
- Rubella Virus causes rubella or German measles, clinically presenting as three-day measles.
Flaviviridae Family
- Hepatitis A (HAV) is transmitted via the fecal-oral route.
- Dengue Virus causes Dengue Hemorrhagic Fever, with serological markers NSAg 1 and 2, IgG, and IgM positive for diagnosis.
- Yellow Fever Virus causes acute viral hemorrhagic disease, with clinical findings of jaundice.
Hepeviridae Family
- Human Hepatitis E Virus (HEV) is transmitted through fecal-oral routes, presenting as fulminant disease in pregnant women.
Hepatitis C Virus (HCV)
- Also known as post-transfusion viral hepatitis, it causes hepatitis C.
- Clinical findings include jaundice and increased liver enzymes.
Rhabdoviridae Family
- Lyssa Virus causes rabies, presenting as a bullet-shaped virus with Negri bodies present in the brain determined through forensic autopsy.
Paramyxoviridae Family
- Measles Virus (Rubeola) leads to measles, with clinical findings of Koplik spots, fever, rash, and respiratory symptoms.
- Mumps Virus causes mumps or parotitis.
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Description
This quiz explores the fundamentals of virology, focusing on the Tobacco Mosaic Virus and its significance in microbial studies. Learn about the structure, function, and historical contributions to the field, especially emphasizing the work of Louis Pasteur and vaccine development in virology.
