UNIT 5 MOD A - LAST EXAM

What are the minimum components of a virus?

• Nucleic acid genome (either DNA or RNA)

• Protein capsid (shell surrounding the genome)

What additional components may be present in some viruses (but not all)?

• Envelope (lipid membrane)

• Glycoprotein spikes

• Viral enzymes (polymerases, replicases, reverse transcriptase)

Where do enveloped viruses obtain their membrane (envelope)?

• From the host cell membrane during viral release

In viral replication, what occurs during Step 1: Adsorption (attachment)?

The virus binds to specific receptors on the surface of a susceptible host cell

In viral replication, what happens during Step 2: Penetration (entry and uncoating)?

The virus enters the host cell, and the capsid is removed to release the viral nucleic acid

In viral replication, what occurs during Step 3: Synthesis?

The host cell machinery is used to produce viral nucleic acid and viral proteins

In viral replication, what happens during Step 4: Assembly?

Newly synthesized viral components are assembled into complete virions.

In viral replication, what occurs during Step 5: Release?

Newly formed viruses exit the host cell, either by budding (enveloped viruses) or cell lysis

How are complete virus particles (virions) put together?

Assembly, during which newly synthesized viral nucleic acid and capsid proteins self-assemble into intact infectious particles.

Define cytopathic effect (CPE):

Virus‑induced damage that alters the microscopic appearance of host cells

Define oncogenicity:

The ability of a virus to induce cancer

Which type of cancer is associated with Epstein‑Barr virus (EBV)?

Burkitt lymphoma

Which cancer is associated with Human herpesvirus 8 (KSHV)?

Kaposi sarcoma

What type of cancer is linked to Hepatitis B virus (HBV) infection?

Hepatocellular carcinoma

Which cancers are associated with certain papillomaviruses (HPV)?

Cervical cancer and penile cancer

What type of cancer is associated with HTLV‑1?

Leukemia

What cancer is associated with Hepatitis C virus (HCV)?

Liver cancer

Define teratogenic:

Capable of causing birth defects by crossing the placenta

Which teratogenic virus is responsible for causing congenital infection when transmitted from mother to fetus and can lead to birth defects?

HIV

Which teratogenic virus is associated with congenital rubella syndrome and birth defects when infection occurs during pregnancy?

Rubella

Which teratogenic virus commonly causes congenital infections and severe complications in fetuses and newborns?

Cytomegalovirus (CMV)

In virology, what is a latent viral infection (as discussed in relation to the lytic cycle and viruses in general)?

The virus enters a dormant phase inside host cells, produces no symptoms, and may reactivate at a later time.

What type of virus causes Smallpox (Variola)—DNA or RNA?

Enveloped DNA virus

What type of skin lesions are produced during Smallpox (Variola) infection?

Eruptive skin pustules called pox (pocks).

How was Smallpox (Variola) eradicated worldwide?

Through global vaccination using the vaccinia virus as part of a WHO effort.

What does it mean when a disease is said to be eradicated?

The disease has been eliminated worldwide, with no naturally occurring cases remaining.

What type of viruses are herpesviruses, and what common clinical feature do they tend to cause?

Herpesviruses are enveloped DNA viruses that tend to cause a rash that spreads or “creeps.”

What does HSV stand for, and what infections does it cause?

Herpes simplex virus, which causes oral and genital herpes.

What does VZV stand for, and what diseases does it cause?

Varicella‑zoster virus, which causes chickenpox and shingles.

What does CMV stand for, and what infection does it cause?

Cytomegalovirus, which causes cytomegalovirus infection.

What does EBV stand for, and what disease does it cause?

Epstein‑Barr virus, which causes infectious mononucleosis.

What do HHV‑6 and HHV‑7 cause?

Roseola.

What does KSHV stand for, and what condition is it associated with?

Kaposi sarcoma–associated herpesvirus, which causes Kaposi sarcoma.

Herpesviruses are very common, and most people encounter at least some of them in their lifetime. For which group of people are these infections more likely to cause serious illness?

Immunocompromised individuals, especially those with AIDS.

Herpes Simplex Virus 1 (HSV-1) is usually characterized by lesions on what part(s) of the body?

Oropharynx, lips, mouth (cold sores)

Herpes Simplex Virus 2 (HSV-2) is usually characterized by lesions on what part(s) of the body?

Genitalia, perineum, buttocks

What systemic symptoms can occur during an HSV‑2 infection?

Painful vesicles

Which genitourinary (pee + reproduction) symptoms may appear in HSV‑2 infections

Dysuria (painful urination) and cervicitis (inflamed cervix)

What happens to HSV‑2 lesions before they heal

They ulcerate prior to healing

How is neonatal herpes acquired

It is acquired during vaginal delivery from an infected mother

Which herpesvirus type is most commonly implicated in neonatal herpes

HSV‑2 is most common

Varicella‑Zoster Virus (VZV) is a member of which virus family

It is a member of the herpesviruses

What disease is caused by Herpes varicella

Chickenpox

What disease is caused by Herpes zoster as a recurrent infection

Shingles

How can varicella be transmitted from person to person

• Respiratory droplets

• Fluid from skin lesions

How long is the incubation period for varicella

10–20 days

When is a person with varicella considered contagious

1–2 days before the rash appears

What systemic symptom is associated with vcv (Varicella‑Zoster Virus)

Fever

What type of rash is associated with varicella

Abundant vesicular rash

What happens to varicella lesions as they resolve

Crusting and healing of lesions

Shingles (herpes zoster) occurs when the dormant virus reemerges.  In what cells does this virus exist in a latent form?

Sensory neuron ganglia

What condition may cause the herpes zoster virus to become active and lead to shingles

Immunosuppression

What medical condition may trigger herpes zoster (shingles) reactivation

Cancer

What event may trigger herpes zoster to become active

Surgery

What type of medical treatment may cause herpes zoster reactivation

X‑ray treatments

What type of therapy may cause herpes zoster to become active

Drug therapy

What cellular changes are characteristic of CMV (Cytomegalovirus) infection

Cells become enlarged (giant) with nuclear and cytoplasmic inclusions

How common is CMV (Cytomegalovirus) in humans

It is one of the most common human infections

How is CMV (Cytomegalovirus) spread through the upper body

• Saliva

• Respiratory mucus

Which bodily fluids involved in infants and children can spread CMV (Cytomegalovirus)

• Milk

• Urine

Which reproductive secretions can transmit CMV (Cytomegalovirus)

• Semen

• Cervical secretions

Because CMV (Cytomegalovirus) can remain latent, many healthy adults are asymptomatic carriers

True

What populations are at an increased risk for severe, disseminated CMV (Cytomegalovirus) infection?

• Fetuses

• Newborns

• Immunodeficient adults

• Organ transplant patient

What lymphatic disease is caused by Epstein‑Barr Virus

Mononucleosis

By midlife, what do most people show regarding EBV (Epstein–Barr virus)

Serological evidence of infection

What complication of EBV (Epstein–Barr virus) infection primarily affects central African children ages 4–8

Burkitt lymphoma

Why are central African children more susceptible to EBV (Epstein–Barr virus) ‑induced Burkitt lymphoma

Chronic coinfection with malaria weakens the immune system, increasing susceptibility to EBV‑induced B‑cell malignancy

Which hepatitis virus is a DNA virus

Hepatitis B (HBV)

Which hepatitis viruses are RNA viruses

Hepatitis A (HAV) and Hepatitis C (HCV)

What do HAV, HBV, and HCV all cause

Hepatitis

What is the endemic status of HAV, HBV, and HCV in the U.S.

All are endemic in the United States

What is a typical incubation period for HAV, HBV, and HCV

Approximately one month

How can HAV, HBV, and HCV be differentiated

By diagnostic testing

Hepatitis viruses target which cells

Hepatocytes (liver cells)

What can happen when hepatocytes are damaged

Bilirubin can accumulate

What condition results from bilirubin buildup causing yellow skin

Jaundice

Which hepatitis viruses have vaccines available for prevention?

• Hepatitis A

• Hepatitis B

Which hepatitis virus has a relatively short duration with mild jaundice, and is transmitted through the fecal-oral route?

Hepatitis A

Who is especially vulnerable to HBV due to sexual exposure

People with multiple sexual partners

Which behavior significantly elevates the risk of HBV (Hep B Virus) transmission

Injection drug use

What type of exposure can lead to HBV infection

Exposure to infected blood

Which work environments place individuals at higher risk for HBV

Occupations involving potential blood exposure

Chronic HBV infection increases the risk for developing what?

Hepatocellular carcinoma

There are a number of ways to treat HBV infections, including treating the symptoms, antivirals, and recombinant interferon.  How can a patient be provided passive artificial immunity to HBV?

Hepatitis B immune globulin (HBIG)

Hepatitis C, is referred to as the “silent epidemic”.  Why?

Often asymptomatic for years

How did blood transfusions before 1985 contribute to HCV (Hepatitis C virus) spread

no HCV screening existed, so transfusions were a major route of HCV transmission

What behavior is a major driver of HCV (Hepatitis C virus) transmission

Sharing needles

Which type of exposure can easily transmit HCV

Direct contact with infected blood from someone infected w/ HCV (Hepatitis C virus)

What condition can HPV (Human papillomavirus) infection lead to

Genital warts (sexually transmitted)

Which HPV (Human Papillomavirus) strains have been identified as the major cancer‑associated types

HPV‑16 and HPV‑18

These high‑risk HPV strains are most strongly linked to which cancers

Cervical cancer and penile cancer

In addition to genital areas, warts caused by various strains of HPV can be found on any mucous membrane or skin surface.  What are some treatment options for removal of warts?

• Podophyllin

• Cauterization

• Freezing

• Laser surgery

What other ways can warts be transmissible?

• Direct contact

• Fomites

• Autoinoculation

The Influenza virus has three distinct types, Influenza A, Influenza B, and Influenza C.  Which of these three is primarily responsible for seasonal outbreaks associated with influenza?

• Influenza A

What role does hemagglutinin play during influenza infection

Attachment to host cells and viral entry

How does neuraminidase assist the influenza virus

It enables viral release and breaks down mucus

Define antigenic shift:

Exchange of viral genes from animal influenza strains

Define antigenic drift:

Gradual mutations over time

What animal reservoir(s) harbor the influenza virus and contribute to constant antigenic shifting?

Birds and pigs

What is the primary way influenza moves between people

Respiratory droplets