Podcast
Questions and Answers
What area of the body does Herpes Simplex Virus type 1 (HSV 1) predominantly affect?
What area of the body does Herpes Simplex Virus type 1 (HSV 1) predominantly affect?
Which of the following is NOT commonly caused by Coxsackie Viruses?
Which of the following is NOT commonly caused by Coxsackie Viruses?
What is a hallmark characteristic of Herpes Simplex Virus type 2 (HSV 2)?
What is a hallmark characteristic of Herpes Simplex Virus type 2 (HSV 2)?
Which virus is primarily responsible for causing chickenpox?
Which virus is primarily responsible for causing chickenpox?
Signup and view all the answers
Which symptom is typical for Hand, Foot and Mouth Disease?
Which symptom is typical for Hand, Foot and Mouth Disease?
Signup and view all the answers
What disease is primarily caused by the Epstein-Barr Virus (EBV)?
What disease is primarily caused by the Epstein-Barr Virus (EBV)?
Signup and view all the answers
Which of the following complications is NOT associated with measles?
Which of the following complications is NOT associated with measles?
Signup and view all the answers
Which age group is most commonly affected by mumps?
Which age group is most commonly affected by mumps?
Signup and view all the answers
How does Epstein-Barr Virus (EBV) persist in the human body after infection?
How does Epstein-Barr Virus (EBV) persist in the human body after infection?
Signup and view all the answers
What symptom is most characteristic of measles?
What symptom is most characteristic of measles?
Signup and view all the answers
What is the chance of a male experiencing testicular pain if infected with mumps after puberty?
What is the chance of a male experiencing testicular pain if infected with mumps after puberty?
Signup and view all the answers
Which type of virus does not include Epstein-Barr Virus (EBV)?
Which type of virus does not include Epstein-Barr Virus (EBV)?
Signup and view all the answers
What is a significant complication associated with measles infection?
What is a significant complication associated with measles infection?
Signup and view all the answers
What is the primary causative agent of chickenpox?
What is the primary causative agent of chickenpox?
Signup and view all the answers
Which symptom is characteristic of chickenpox?
Which symptom is characteristic of chickenpox?
Signup and view all the answers
How is hand, foot, and mouth disease primarily transmitted?
How is hand, foot, and mouth disease primarily transmitted?
Signup and view all the answers
What is the seasonal occurrence pattern of herpangina?
What is the seasonal occurrence pattern of herpangina?
Signup and view all the answers
Which virus is known to infect most individuals during early childhood?
Which virus is known to infect most individuals during early childhood?
Signup and view all the answers
What is a common symptom of shingles?
What is a common symptom of shingles?
Signup and view all the answers
Varicella infection is generally considered ____ in children.
Varicella infection is generally considered ____ in children.
Signup and view all the answers
Which of the following is NOT a common feature of hand, foot, and mouth disease?
Which of the following is NOT a common feature of hand, foot, and mouth disease?
Signup and view all the answers
Which condition is characterized by vesicles in the mouth and affects the faecal/oral route?
Which condition is characterized by vesicles in the mouth and affects the faecal/oral route?
Signup and view all the answers
What is the incubation period for Varicella?
What is the incubation period for Varicella?
Signup and view all the answers
What characterizes the viral genome of vinis?
What characterizes the viral genome of vinis?
Signup and view all the answers
Which component of a virus gives it symmetry and protects the nucleic acid core?
Which component of a virus gives it symmetry and protects the nucleic acid core?
Signup and view all the answers
What defines viruses as obligate intracellular parasites?
What defines viruses as obligate intracellular parasites?
Signup and view all the answers
What is a common characteristic of the icosahedral type of viral capsid?
What is a common characteristic of the icosahedral type of viral capsid?
Signup and view all the answers
Which viral infection is known to potentially lead to Ramsay Hunt syndrome?
Which viral infection is known to potentially lead to Ramsay Hunt syndrome?
Signup and view all the answers
What is a complication associated with the Epstein-Barr Virus?
What is a complication associated with the Epstein-Barr Virus?
Signup and view all the answers
How is herpangina commonly presented in children?
How is herpangina commonly presented in children?
Signup and view all the answers
Which factor is NOT involved in tissue tropism for viral infections?
Which factor is NOT involved in tissue tropism for viral infections?
Signup and view all the answers
What is the primary distinction between lytic and lysogenic replication of viruses?
What is the primary distinction between lytic and lysogenic replication of viruses?
Signup and view all the answers
Which of the following viruses is associated with persistent infections?
Which of the following viruses is associated with persistent infections?
Signup and view all the answers
What role do capsomeres play in the viral assembly process?
What role do capsomeres play in the viral assembly process?
Signup and view all the answers
Which characteristic best defines viral latency?
Which characteristic best defines viral latency?
Signup and view all the answers
How does viral persistence differ from chronic viral infections?
How does viral persistence differ from chronic viral infections?
Signup and view all the answers
What is a critical step in viral replication once a virus has entered a host cell?
What is a critical step in viral replication once a virus has entered a host cell?
Signup and view all the answers
Which virus is known for having significant dental implications due to its association with oral lesions?
Which virus is known for having significant dental implications due to its association with oral lesions?
Signup and view all the answers
How do viruses demonstrate tropism towards specific cell types?
How do viruses demonstrate tropism towards specific cell types?
Signup and view all the answers
Which classification of viruses is based on the arrangement of their structural proteins?
Which classification of viruses is based on the arrangement of their structural proteins?
Signup and view all the answers
What best defines persistent viral infections?
What best defines persistent viral infections?
Signup and view all the answers
Which type of nucleic acid can be found in viruses?
Which type of nucleic acid can be found in viruses?
Signup and view all the answers
What distinguishes an icosahedral virus structure?
What distinguishes an icosahedral virus structure?
Signup and view all the answers
Which of the following statements about viral entry into host cells is false?
Which of the following statements about viral entry into host cells is false?
Signup and view all the answers
What is the primary function of transcription in the viral replication process?
What is the primary function of transcription in the viral replication process?
Signup and view all the answers
Which of the following best describes how viruses achieve cellular tropism?
Which of the following best describes how viruses achieve cellular tropism?
Signup and view all the answers
Which process describes how viruses penetrate host cells after attachment?
Which process describes how viruses penetrate host cells after attachment?
Signup and view all the answers
Which viral classification is characterized by high mutation rates compared to DNA viruses?
Which viral classification is characterized by high mutation rates compared to DNA viruses?
Signup and view all the answers
During which phase of viral replication can the virus not be detected in the host cell, indicating a 'pause' in infectivity?
During which phase of viral replication can the virus not be detected in the host cell, indicating a 'pause' in infectivity?
Signup and view all the answers
What is a key characteristic of persistent viral infections?
What is a key characteristic of persistent viral infections?
Signup and view all the answers
Which of the following viruses is known for its significant implications in dental health?
Which of the following viruses is known for its significant implications in dental health?
Signup and view all the answers
What is the key difference between endocytosis and fusion in the context of viral penetration?
What is the key difference between endocytosis and fusion in the context of viral penetration?
Signup and view all the answers
Study Notes
Varicella-Zoster
- Caused by human herpes virus 3
- Commonly known as chickenpox and shingles
- Chickenpox usually mild and self-managed
- Chickenpox can be more serious if contracted in adulthood
- Chickenpox has a 2 week incubation period
- Symptoms include fever, rash, papules becoming vesicular and itchy, but painless
- Shingles are a reactivation of the varicella-zoster virus
- Shingles manifest as painful vesicular rash
- Shingles occur in dorsal root ganglia and trigeminal nerve
Ramsay Hunt Syndrome
- A rare form of shingles
- Affects the facial nerve
- Symptoms include vesicular rash on the tympanic membrane and auditory canal
- Causes unilateral facial palsy
Hand Foot & Mouth Disease
- Primarily caused by group A coxsackie viruses
- Symptoms include malaise and spots on buttocks, groin, hands and feet
- Transmission through air, coughing, faecal contact and contaminated objects
- Common outbreak in nurseries
Herpangina
- Symptoms include vesicles in the mouth, malaise and sore throat
- Caused by Coxsackie A virus
- Primarily occurs in summer
- Transmission through faecal-oral route or air droplets
- Self-managed
Epstein-Barr Virus (EBV)
- Also known as Human Herpesvirus 4
- Most people are infected in early childhood
- When contracted in teens or young adulthood can cause infectious mononucleosis aka glandular fever
- EBV becomes dormant and people remain infected for life
- EBV lives in latent form in B-lymphocytes
- Human are the only known host
- EBV can cause:
- Glandular fever
- Burkitt’s Lymphoma
- Nasopharyngeal carcinoma
- Oral Hairy Leukoplasia
Mumps
- Usually a childhood illness
- Causes parotitis (inflammation of the salivary glands)
- Causes painful swelling
- If contracted after puberty males can have pain and swelling of the testicle
- One in 20 females can get swelling of the ovaries
- One in 20 can have temporary hearing loss
- One in 1000 can get viral meningitis
- One in 20 can get acute pancreatitis
Measles
- Also known as measles morbillivirus
- Most highly infectious disease known
- Transmitted by air droplets and surfaces
- Causes a characteristic exanthematous rash
- Enters the body through the respiratory tract
- Associated symptoms include headache, fever, sore throat and Koplik’s spots
-
Complications include:
- Stillbirth and miscarriage in pregnancy
- Vision loss
- Subacute sclerosing panencephalitis (rare, fatal brain complication)
- Fits and seizures
- Encephalitis
Koplik’s Spots
- White spots with a red halo on the inside of the cheek
- Characteristic of measles
Herpes Simplex (HSV 1 & 2)
- HSV 1 generally causes orofacial lesions (above the belt)
- HSV 2 generally causes genital lesions (below the belt)
Viral Genome
- Contains either DNA or RNA, never both.
- Can be linear or circular, single stranded, or double stranded.
Capsid
- Protective outer layer of the virus.
- Surrounds the nucleic acid core.
- Composed of numerous subunits called capsomers.
- Provides symmetry and is made of proteins called protomers.
Envelope
- Surrounds the nucleocapsid.
- Bilayer of lipoprotein and glycoproteins.
- Viruses without an envelope are called "naked viruses."
Enzymes
- Play a crucial role in the infection process.
- Some enzymes contain their own nucleic acid polymerases that transcribe the viral genome into mRNA during replication.
Obligate Intracellular Parasites
- Viruses can only multiply within a living host cell.
Icosahedral Viruses
- Polygonal shape.
- Capsid has 12 corners, 20 facets (equilateral triangles), and 30 edges.
- Most stable type of virus.
- Found in human pathogenic viruses such as herpes.
Filamentous Viruses
- Linear, thin, thread-like or rod-shaped.
Head-Tail Viruses
- Icosahedral head.
- Filamentous body.
Viral Tropism
- Refers to the specific host cells, tissues, or organisms that a virus can infect.
- Influenced by:
- Presence of cellular receptors for viral entry.
- Availability of transcription factors for viral replication.
- Cellular receptors of proteins on the cell or viral surface.
Varicella-Zoster Virus (Human Herpesvirus 3)
- Causes chickenpox in children and shingles in adults.
Management of Varicella-Zoster Virus
- Hydration.
- Good diet.
- Non-steroidal anti-inflammatory drugs (NSAIDS) for fever relief (e.g., paracetamol, ibuprofen).
Shingles
- Reactivation of the varicella-zoster virus.
- The virus resides in the dorsal root ganglia.
- Reactivation triggered by trauma, immunosuppressant drugs, or other unknown factors.
- Dormant virus travels through nerve fibers to the skin when reactivated causing unilateral rash.
Management of Shingles
- Requires medical management.
- Can lead to Ramsay Hunt syndrome (shingles of the facial nerve) which causes:
- Unilateral facial palsy.
- Tinnitus.
- Change or loss of taste.
- Dry mouth.
- Oral manifestations.
- Potential for toothache-like pain due to hyposensitivity.
Herpangina
- Viral infection presenting on the soft palate.
- Affects children aged 3-10 years old.
- Symptoms last for up to 10 days.
- Contagious for 3-8 weeks after infection.
- Can cause difficulty swallowing.
Epstein-Barr Virus (Human Herpesvirus 4)
- Can cause various conditions, including Burkitt's lymphoma.
Virus Replication
- Viral replication begins with the attachment of the virus to the host cell.
- Following attachment, penetration occurs, allowing the virus or its genome to enter the host cell.
- Penetration can happen via endocytosis, fusion, or translocation.
- After penetration, the virus undergoes uncoating, where the lipid membrane and protein capsid surrounding the nucleic core are removed.
- The viral nucleic acid becomes free and acts as a template for mRNA synthesis.
- Transcription occurs, producing mRNA that encodes enzymes necessary for viral replication.
- Viruses take advantage of the existing cell structures to replicate themselves.
Viral Release
- Lytic replication results in the death of the host cell.
- Lysogenic replication allows the host cell to continue living and functioning normally.
Viral Persistence
- Persistent infections are characterized by the continuous presence of the virus within the host, without necessarily causing immediate death or significant damage to the host cells.
- Examples of persistent viral infections include HIV, Epstein-Barr, Human Cytomegalovirus.
Viral Latency
- Virus latency is the ability of a virus to remain dormant within a cell, characterized as the lysogenic part of the viral life cycle.
- Latent viral infections are a type of persistent infection, distinct from chronic viral infections.
Viral Tropism
- Viral tropism describes the selective ability of a virus to infect specific cells, tissues, or host species.
- Viral tropism is determined by the presence of specific receptors on the host cell that the virus can bind to.
Features of Viruses
- Viruses are infectious particles that reproduce by hijacking the machinery of a host cell.
- Viruses consist of a DNA or RNA genome enclosed within a protein shell called a capsid.
- Some viruses possess an external membrane envelope.
- Viruses exhibit diverse shapes, structures, genome types, and host preferences.
- Viruses reproduce by infecting host cells and reprogramming them to produce more viruses.
Classification of Viruses
- Viruses are classified based on their symmetry and nucleic acid type.
- Symmetry can be icosahedral, filamentous, or head-tail.
- Nucleic acid can be DNA or RNA, with variations in strandedness (single or double) and type (DNA or RNA).
Key Structures of Viruses
- The capsid encloses the viral genome, providing structural integrity.
- The nucleocapsid consists of the viral genome and associated proteins.
- The envelope, if present, is a lipid bilayer surrounding the capsid.
- Viral enzymes facilitate various steps in the replication process.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz covers important infectious diseases such as varicella-zoster, Ramsay Hunt Syndrome, and Hand Foot & Mouth Disease. It includes information on causes, symptoms, transmission, and complications associated with these conditions. Test your knowledge on these diseases and their impact on health.
