Lecture 3: DNA Viruses and Diseases
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Questions and Answers

What is a potential consequence of a pregnant woman experiencing a blood disorder that affects RBC?

  • Higher risk of abortion (correct)
  • Increased chances of arthritis
  • High likelihood of fetug's rapid RBC replication
  • Development of autoimmune diseases

Why do RBC attach to the virus mentioned?

  • To increase the severity of autoimmune reactions
  • To initiate the replication cycle
  • To facilitate the virus's rapid division (correct)
  • To enhance the symptoms of anemia

What condition can a mother with an autoimmune disorder experience during pregnancy?

  • No impact on pregnancy
  • Growth of additional blood vessels
  • Severe fatigue without symptoms
  • Mild symptoms affecting fetug's development (correct)

How does the rapid division of fetug's RBC affect the fetus?

<p>It may lead to joint pain. (A)</p> Signup and view all the answers

What is a potential impact on the fetus if a pregnant lady is immunocompromised?

<p>Complications leading to abortion (B)</p> Signup and view all the answers

What symptom might a pregnant woman with a particular blood disorder NOT experience?

<p>Absence of autoimmune reactions (C)</p> Signup and view all the answers

Which of the following is a characteristic of the herpesvirus family?

<p>It has a latent infection phase with LATs. (A)</p> Signup and view all the answers

What type of viruses does the Papillomaviridae family primarily consist of?

<p>High risk and low risk types associated with different diseases. (D)</p> Signup and view all the answers

How does the human papillomavirus (HPV) contribute to cervical neoplasia?

<p>By integrating its genome into the host genome. (B)</p> Signup and view all the answers

Which of the following statements regarding latent herpes infections is incorrect?

<p>Virus proteins accumulate continually during latency. (C)</p> Signup and view all the answers

What is the primary method of infection for herpesviruses?

<p>Endocytosis via cell receptors. (B)</p> Signup and view all the answers

What potential risk is associated with Simian virus (SV 40) concerning vaccination?

<p>It is capable of transforming host cells. (A)</p> Signup and view all the answers

Which receptor is predominantly used by herpes simplex viruses for cellular binding?

<p>Nectin and heparan sulfate. (D)</p> Signup and view all the answers

Which of the following symptoms is NOT typically associated with herpesvirus infections?

<p>Acute respiratory illness. (D)</p> Signup and view all the answers

What distinguishes high-risk strains of HPV from low-risk strains?

<p>High-risk strains can integrate into the host genome. (A)</p> Signup and view all the answers

What is the primary characteristic of parvoviruses regarding their structure?

<p>They are among the smallest viruses, ranging from 18-26 nm in diameter. (A)</p> Signup and view all the answers

Which subfamily of parvoviruses specifically infects vertebrates?

<p>Parvovirinae (D)</p> Signup and view all the answers

What is the main mode of replication for Orthopoxvirus?

<p>Cytoplasmic replication using its own enzymes (C)</p> Signup and view all the answers

What critical requirement do parvoviruses have for their replication process?

<p>Host proteins. (C)</p> Signup and view all the answers

Which clade of monkeypox caused an outbreak in 2022-2023?

<p>Clade IIb (B)</p> Signup and view all the answers

Which of the following viruses is associated with direct contact transmission in humans?

<p>Molluscum contagiosum (D)</p> Signup and view all the answers

What is the typical host cell targeted by parvovirus B19?

<p>Red blood cell precursors (A)</p> Signup and view all the answers

Which virus is recognized as the etiological agent for smallpox disease?

<p>Variola (A)</p> Signup and view all the answers

Which condition is NOT typically associated with infection by parvovirus B19?

<p>Chronic fatigue syndrome (D)</p> Signup and view all the answers

What is a key characteristic that distinguishes Orthopoxvirus from varicella-zoster infections?

<p>Type of vaccination available (D)</p> Signup and view all the answers

What is the significance of blood group P antigen in parvovirus infections?

<p>It acts as a receptor for viral attachment. (A)</p> Signup and view all the answers

Which animal is primarily associated with the transmission of Yatapoxvirus to humans?

<p>African monkeys (B)</p> Signup and view all the answers

What condition can parvovirus B19 potentially cause in pregnant women?

<p>Hydrops foetalis (D)</p> Signup and view all the answers

What is a common misconception about the correlation between smallpox and varicella-zoster vaccines?

<p>Both provide complete immunity to all poxviruses (D)</p> Signup and view all the answers

Which of the following best describes the capsid structure of parvoviruses?

<p>Naked with a simple icosahedral shape. (C)</p> Signup and view all the answers

What is a common feature of the Densovirinae subfamily of parvoviruses?

<p>They are known to infect invertebrates. (C)</p> Signup and view all the answers

Which poxvirus is responsible for conditions commonly found in pigs?

<p>Swinepox virus (D)</p> Signup and view all the answers

Which of the following statements about monkeypox is true?

<p>Most infected individuals recover without severe complications. (A)</p> Signup and view all the answers

Parvovirus B19 is most commonly associated with which of the following symptoms?

<p>Slapped cheek appearance (C)</p> Signup and view all the answers

What differentiates the infections caused by Avipoxvirus and Capripoxvirus?

<p>Species affected (birds vs. sheep) (C)</p> Signup and view all the answers

What is the potential reservoir for the virus that can transmit to humans?

<p>Nonhuman primates (D)</p> Signup and view all the answers

Which clade of Mpox is primarily linked to more serious illness and a higher mortality rate?

<p>Clade 1 (D)</p> Signup and view all the answers

What is one of the primary methods of transmission of the Mpox virus between humans?

<p>Close contact (A)</p> Signup and view all the answers

What symptom typically develops last in the progression of Mpox in humans?

<p>Rash with pustules (A)</p> Signup and view all the answers

Which antiviral drug is mentioned as a treatment option for Mpox?

<p>Cidofovir (A)</p> Signup and view all the answers

What is the initial recovery period for Mpox in humans?

<p>5 days (C)</p> Signup and view all the answers

Which of the following symptoms is not associated with Mpox?

<p>Nausea (B)</p> Signup and view all the answers

In which region does Clade 2 of Mpox primarily spread?

<p>West Africa (B)</p> Signup and view all the answers

What chance is there for Clade 2 to cause death compared to Clade 1?

<p>Less severe than Clade 1 (C)</p> Signup and view all the answers

What causes the blisters associated with Mpox?

<p>Viral replication (C)</p> Signup and view all the answers

Flashcards

dsDNA Viruses

Double-stranded DNA viruses, a significant group of viruses with DNA as their genetic material.

Herpesviridae

A family of DNA viruses that cause various diseases like chickenpox, shingles and herpes.

Latency-Associated Transcripts (LATs)

RNA that are synthesized in latent herpes infections, inhibiting apoptosis (cell death) and maintaining neuron survival.

HPV (Human Papillomavirus)

A group of DNA viruses associated with skin warts, genital warts, and cervical cancer.

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High-risk HPV

HPV types linked to cervical cancer (e.g., types 16, 18, 31).

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Low-risk HPV

HPV types linked to skin warts and less severe diseases.

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SV40 (Simian Virus 40)

A DNA virus that can cause disease in humans, in some cases, linked to polio vaccine contamination.

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Icosahedral capsid

A common viral structure characteristic—a geometrically symmetrical shell surrounding the virus’ genetic materials.

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Viral Genome Integration

Mechanism for the viral genome to be incorporated into the host genome.

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Poxviridae

A family of enveloped viruses that includes several human and animal pathogens.

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Orthopoxvirus

A genus within Poxviridae, containing viruses like smallpox and monkeypox.

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Vaccinia

A live virus used as a smallpox vaccine.

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Monkeypox (Mpox)

A viral infection similar to smallpox, mostly from animals.

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Smallpox

A highly contagious viral disease, eradicated globally.

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Avipoxvirus

A poxvirus affecting birds, like fowlpox.

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Molluscipoxvirus

Causes molluscum contagiosum (skin warts) in humans. Often spread by contact.

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Parapoxvirus

Causes orf virus/milker's nodules, primarily in animals.

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Suipoxvirus

Causes swinepox, affecting pigs.

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Yatapoxvirus

Infects monkeys and can spread to humans, causing similar lesions.

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Mpox Transmission

Mpox spreads from animals to humans and between humans through close contact.

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Mpox Symptoms

Mpox causes flu-like symptoms, itchy rash, swollen lymph nodes, fever, headache, backaches, fatigue, and muscle aches. Blisters develop, scab, and fall off.

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Mpox Reservoir

Wild animals, potentially non-human primates, are the source of Mpox.

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Clade I

Central African strain of Mpox, often more severe and leading to more deaths.

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Clade II

West African strain of Mpox, usually less severe than Clade I.

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Recovery Period

Mpox recovery typically takes 2-4 weeks, as blisters scab and fall off.

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Zoonotic Infection

A disease that can spread from animals to humans.

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Incubation Period

The time between infection and the appearance of symptoms (e.g., 2-3 weeks).

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Viral pustule

A filled blister with fluid or pus.

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Treatment Options

No specific antiviral drugs, but drugs like cidofovir and tecovirimat exist and have been repurposed.

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ssDNA viruses

Single-stranded DNA viruses, including parvoviruses.

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Parvoviruses

A group of small, naked ssDNA viruses that infect vertebrates and invertebrates.

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Parvovirus B19

A specific parvovirus that infects red blood cell precursors, potentially causing fifth disease.

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Fifth disease

A viral infection characterized by a 'slapped cheek' appearance and potentially acute arthritis, aplastic anemia, and hydrops foetalis.

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Hydrops foetalis

A potentially fatal condition affecting a fetus, possibly transmitted from a pregnant woman with parvovirus.

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Naked virus

Viruses without an outer envelope.

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Red Blood Cell Precursors

Cells that develop into functioning red blood cells in the bone marrow.

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Microtubules

Cellular structures used for transport within the cell.

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Blood group P antigen

The receptor on red blood cells to which parvovirus B19 (a specific parvovirus) attaches.

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Parvoviridae subfamilies

Parvovirinae (vertebrate viruses) and Densovirinae (invertebrate viruses).

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Rapid RBC replication

Red blood cells (RBCs) divide very quickly

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RBC precursor

An immature form of a red blood cell

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Autoimmune Anemia

Blood disorder in which the body attacks its own red blood cells

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Pregnant lady (mother) mild symptom

Pregnant women may have minor symptoms which could indicate fetal RBC division.

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Fetal RBC rapid division

Embryonic red blood cell division during pregnancy.

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Virus Transmission (fetus)

Rapid fetal RBC division could facilitate virus transmission.

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Study Notes

Lecture 3: DNA Viruses and Diseases

  • Herpesviridae (human herpesviruses, HHV) are a group of viruses causing various diseases.
  • HHV types and their associated diseases are diverse. HHV-1 and HHV-2 are associated with oral and genital herpes, respectively. HHV-3 causes chickenpox and shingles. HHV-4 (Epstein-Barr virus, EBV) is linked to infectious mononucleosis and some cancers. HHV-5 (Cytomegalovirus, CMV) can cause mild or asymptomatic infections, but can be severe in pregnant women. HHV-6 and HHV-8 cause roseola and Kaposi's sarcoma, respectively.
  • Herpesviruses have a characteristic icosahedral capsid surrounded by a tegument containing proteins and viral mRNA. They have an envelope with glycoproteins, cellular binding proteins (e.g., heparan sulfate), and main receptors (e.g., nectins).
  • Herpesvirus infections often involve endocytosis and replication in the nucleus.
  • Latent herpes infections occur when the viral genome is inactive, replicating only a few RNA (latency-associated transcripts, LATs) and not expressing viral proteins. However, latent CMV infections in memory B cells maintain viral genome copies during cell division.

Latent Herpes Infections

  • Viral genome is inactive, but a few RNA are synthesized (latency-associated transcripts, LATs).
  • No viral protein synthesis.
  • LATs inhibit apoptosis to ensure neuron survival.
  • An exception is latent CMV infection in memory B cells; virus synthesizes proteins to maintain viral genome copy number during B cell division.

Papillomaviridae (Human Papillomaviruses, HPV)

  • High-risk HPV types (16, 18, and 31) are linked to cervical neoplasia.
  • Low-risk HPV types (6 and 11) cause skin warts and infections in the vocal chords and respiratory tracts (genital warts).
  • HPV infection does not kill cells; viral genome may integrate into the host genome or exist as episomes in transformed cells.
  • High-risk E6 and E7 can transform primary human keratinocytes.

Polyomaviridae (e.g., SV 40)

  • Simian virus 40 (SV 40) was introduced to humans via a contaminated Sabin polio vaccine.
  • Propagated in African green monkey kidney cells (Vero).
  • Adheres to MHC class 1.
  • Associated with neural tumors and mesothelioma (along with asbestos) in humans.

Poxviridae

  • Brick-shaped and enveloped.
  • Biconcave capsid.
  • Replicate in the cytoplasm and carry their own enzymes for mRNA synthesis.

Additional Viral Information

  • Orthopoxviruses include vaccinia (live smallpox vaccine, eradicated globally) and variola (smallpox).
  • Clade IIb of variola causes less severe cases of monkeypox (Mpox) compared to Clade I.
  • Monkeypox (Mpox) is an orthopoxvirus.
  • Various other poxvirus types are found in a variety of animal hosts.

Lecture 4: Single-Stranded DNA Viruses

  • Parvoviridae, particularly parvoviruses, are among the smallest DNA viruses.
  • Two subgroups include parvovirinae (vertebrate) and densovirinae (invertebrate) viruses.
  • Parvoviruses carry either a + strand or - strand DNA.
  • Parvoviruses attach to erythrocyte precursor (RBC precursor cells) via blood group P antigen, enter the cell by endocytosis, and are transported to the nucleus via microtubules.
  • Replication depends on host proteins.
  • Autonomous parvoviruses, such as Parvovirus B19, infect red blood cell precursors and are associated with fifth disease (erythema infectiosum) and other conditions.

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Explore the different types of Herpesviridae and the diseases they cause. This quiz covers key features of these viruses, their transmission, and the implications of infections. Test your knowledge on HHV types, symptoms, and viral behavior.

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