Chapter 12 Viral diseases

What are the steps involved in viral infection of an animal cell in order?

The steps involved are attachment, penetration, uncoating, synthesis of viral components, assembly, and release.

What is the difference between bacteriophage and animal viral multiplication?

Bacteriophages inject only their nucleic acid into the host cell, whereas animal viruses enter as a complete virion and undergo uncoating inside the cell.

What factors influence the occurrence of viral diseases?

The occurrence of viral diseases is influenced by host immunity, viral virulence, environmental conditions, dose of virus, and portal of entry.

What are the different pathogenic properties of viruses?

Viruses cause disease through cytopathic effects, immune responses, persistent infections, and the ability to transform host cells.

What are cytopathic effects?

Cytopathic effects are visible structural changes or damage in host cells caused by viral infection.

What are syncytia?

Syncytia are multinucleated giant cells formed by the fusion of infected host cells.

What are inclusion bodies?

Inclusion bodies are intracellular accumulations of viral particles or proteins within infected cells.

What are Negri bodies?

Negri bodies are cytoplasmic inclusion bodies found in neurons that are characteristic of rabies infection.

What is contact inhibition?

Contact inhibition is the property of normal cells to stop growing when they come into contact with other cells.

What are oncogenic viruses?

Oncogenic viruses are viruses that can cause cancer and include both DNA oncogenic viruses and RNA oncogenic viruses.

What is the difference between latent viral infection and persistent viral infection?

A latent viral infection remains dormant in the host and can reactivate later, whereas a persistent viral infection continuously produces virus over time.

What are viral virulence factors?

Viral virulence factors are mechanisms that enhance a virus’s ability to infect, replicate, and evade the host immune response.

What categories of genes influence viral virulence?

The categories of genes that influence viral virulence include genes involved in viral entry, replication, and immune evasion.

What are alternative names for different viral infections?

Measles is also known as rubeola, and German measles is also known as rubella.

What causes smallpox?

Smallpox is caused by the variola virus.

What is the historical context of smallpox?

Smallpox was a highly deadly disease historically.

What was Edward Jenner's contribution to smallpox?

Edward Jenner developed the first successful vaccine for smallpox.

Is smallpox still an active threat? Why or why not?

Smallpox is not an active threat because it has been eradicated worldwide through vaccination.

What is the mode of transmission of viruses?

Viruses are transmitted through respiratory droplets, direct contact, bodily fluids, and vectors.

Is a vaccine available for smallpox?

Yes, a vaccine is available for smallpox and was used to eradicate the disease.

What causes mpox?

Mpox is caused by the monkeypox virus.

Is mpox a zoonotic disease?

Yes, mpox is a zoonotic disease.

How can mpox be prevented?

Mpox can be prevented by avoiding contact with infected animals or individuals and through vaccination.

What are warts?

Warts are benign skin growths caused by human papillomavirus.

How are warts transmitted?

Warts are transmitted through direct contact.

What causes chickenpox?

Chickenpox is caused by varicella-zoster virus.

What is Reye’s syndrome?

Reye’s syndrome is a rare condition causing swelling of the liver and brain.

What is shingles?

Shingles is the reactivation of latent varicella-zoster virus that travels along peripheral nerves to the skin, follows the distribution of cutaneous sensory nerves, and is usually limited to one side of the body.

What causes chickenpox and shingles?

Both chickenpox and shingles are caused by varicella-zoster virus.

What happens to VZV after the primary infection causing chickenpox?

After primary infection, varicella-zoster virus remains dormant in sensory nerve ganglia in the host body.

What is the mode of transmission for varicella-zoster virus?

Varicella-zoster virus is transmitted through respiratory droplets and direct contact with lesions.

Does everyone with a chickenpox infection in their childhood develop shingles later in life?

Not everyone who has chickenpox develops shingles later in life.

What are the predisposing conditions for developing shingles?

Predisposing conditions include aging and immunosuppression.

What are the signs and symptoms of chickenpox and shingles?

Chickenpox presents with fever and a vesicular rash, while shingles presents with a painful localized rash.

What causes measles (rubeola)?

Measles is caused by the measles virus.

How contagious is measles?

Measles is highly contagious.

Who are the susceptible groups for measles?

Susceptible groups include unvaccinated individuals and immunocompromised individuals.

What is the mode of transmission for measles?

Measles is transmitted through respiratory droplets and airborne spread.

What are the signs and symptoms of measles?

Measles presents with fever, cough, conjunctivitis, Koplik’s spots, and a rash.

What is immune amnesia?

Immune amnesia is the loss of immune memory.

What viral infection causes immune amnesia?

Immune amnesia is caused by measles infection.

What are Koplik’s spots?

Koplik’s spots are small white lesions on the buccal mucosa characteristic of measles.

What is the prevention for measles?

Measles is prevented by the MMR vaccination.

What is German measles?

German measles is also known as rubella.

What causes German measles?

German measles is caused by the rubella virus.

What is the mode of transmission for rubella?

Rubella is transmitted through respiratory droplets.

What is congenital rubella syndrome?

Congenital rubella syndrome occurs when the virus infects a fetus causing developmental defects.

What are the signs and symptoms of rubella?

Rubella presents with rash, fever, and lymphadenopathy.

What are the prevention strategies for rubella?

Rubella is prevented through the MMR vaccine.

What causes poliomyelitis?

Poliomyelitis is caused by poliovirus.

How is poliomyelitis transmitted?

Poliomyelitis is transmitted through the fecal-oral route.

What are the symptoms of poliomyelitis?

Symptoms range from mild illness to paralysis.

What is an iron lung?

An iron lung is a device used to assist breathing in paralyzed patients.

What are the two types of vaccines?

The two types of vaccines are live attenuated vaccines and inactivated vaccines.

What causes rabies?

Rabies is caused by the rabies virus.

What are the different susceptible hosts for rabies?

Susceptible hosts include mammals such as dogs, bats, raccoons, and humans.

What is the mode of transmission of rabies?

Rabies is transmitted through the bite of an infected animal via saliva.

What is the pathology of rabies infection?

Rabies causes infection of the central nervous system leading to encephalitis.

What are some viral infections that can be transmitted from mother to fetus?

Examples include rubella, cytomegalovirus, and Zika virus.

What are the different ways that Zika virus can be transmitted?

Zika virus is transmitted through mosquito bites, sexual contact, and from mother to fetus.

What causes arboviral encephalitis?

Arboviral encephalitis is caused by viruses transmitted by arthropods such as mosquitoes.

What does the EBV cause?

Epstein-Barr virus causes infectious mononucleosis.

What diseases are associated with EBV infection?

Epstein-Barr virus is associated with infectious mononucleosis and certain cancers.

What are some upper and lower respiratory tract viral infections?

Upper respiratory tract infections include the common cold, and lower respiratory tract infections include influenza and pneumonia.

What does HIV target?

HIV targets CD4 T-helper cells.

What can untreated HIV lead to?

Untreated HIV can lead to AIDS.

What is the mode of transmission of HIV?

HIV is transmitted through blood, sexual contact, shared needles, and from mother to child.

What are the different stages of HIV infection?

The stages of HIV infection are the acute stage, the latency stage, and AIDS.

What is the most severe phase of HIV infection?

The most severe phase is AIDS, which leads to immune system failure and opportunistic infections.

What are prions?

Prions are infectious proteins that lack nucleic acids.

How are prions different from viruses?

Prions differ from viruses in that they lack genetic material.

What happens to the brain during a prion infection?

Prion infections cause spongiform degeneration of the brain.

What are some prion diseases discussed in class?

Examples include Creutzfeldt-Jakob disease and mad cow disease.