Medical Bacteriology Exam 3

Viruses belonging to which of the following groups are likely to establish latent infections?

Herpesviruses

What viral protein of the Ebola virus interferes with the immune process?

the VP35 protein suppresses the host immune response by blocking RIG-I-like receptor signaling, which normally detects viral RNA and triggers interferon production which allows Ebola to evade innate immunity, allowing uncontrolled replication and severe disease

Small viruses are in the same size range as which of the following?

Eukaryotic ribosomes

What is the route of entry for adenovirus?

Respiratory tract (via inhalation) because adenoviruses cause respiratory infections

What is the route for coronavirus?

Respiratory tract (via inhalation) because coronavirus causes respiratory illnesses such as the common cold or SARS

What is the route of entry for hepadnavirus?

Parenteral (through blood, sexual contact, mother-to-child) because hepadnavirus (Hepatitis B) causes illness through bloodborne and sexual transmission

What is the route of entry for Paramyxovirus?

Through the respiratory tract (via inhalation) because the paramyxovirus causes measles and mumps through airborne droplets 

What is the route of entry for Poxvirus?

The skin (through abrasions or direct contact)

• an example is smallpox (variola) which enters through the skin via lesions or mucosa

Which of the following licensed virus vaccines is a subunit vaccine prepared using recombinant DNA technology?

Papilloma

Which of the following viruses is the most common cause of neonatal infections in the United States?

Cytomegalovirus

Which of the following poxviruses infects only humans?

molluscum contagiosum

A 37-year-old emergency room nurse is vaccinated for smallpox because of the bioterrorism threat. Twelve days later, she has a major complication from the vaccine. Vaccinia immune globulin therapy is considered. For which of the following conditions is treatment with vaccinia immune globulin of NO benefit?

Postvaccinial encephalitis 

The eradication of smallpox was facilitated by several features of the virus. Which one of the following contributed least to eradication?

It multiplies in the cytoplasm of infected cells

Vaccination with the vaccinia (smallpox) vaccine protects against infections by the following poxviruses except:

Molluscum contagiosum

Which of the following descriptions of or statements about Lassa fever is correct?

It occurs from contact with the house rat Mastomys natalensis

Yellow fever occurs in which region or regions of the world?

Africa and South America

African hemorrhagic fevers, Marburg and Ebola, are severe diseases often ending in death. Which of the following is most accurate about Ebola virus?

It is spread by contact with blood or other body fluids 

Which of the following diseases occurring in the United States lacks a known vector?

Hantavirus pulmonary syndrome 

Cellular oncogenes represent activated genes involved in cancer. A second class of cancer genes is involved in cancer development only when both alleles of such a gene are inactivated. The second class of genes is called:

Tumor suppressor genes

What are the causative viral agents of human cervical cancer?

Human papillomavirus (HPV) is the primary cause of most cervical cancers by encoding oncoproteins (E6 and E7) that inactivate tumor suppressor genes p53 and Rb, leading to uncontrolled cell growth.

__________ encode an enzyme called reverse transcriptase

Retroviruses

What is the function of reverse transcriptase in retroviruses?

Convert their RNA genetic material into DNA.

o   This process is crucial because once the viral RNA is reverse-transcribed into DNA, the resulting viral DNA is integrated into the host cell's chromosome (becoming a provirus), where it can remain dormant or become active to produce new viruses.

·       Retroviruses (like HIV) use reverse transcriptase to synthesize DNA from their RNA genome.

·       This DNA is then inserted into the host genome, allowing the virus to persist and replicate using the host's cellular machinery.

Human papillomavirus can cause cancer in humans and is most commonly associated with

Anogenital cancers

Which of the following best describes available HPV vaccines?

Noninfectious subunit

What are the symptoms typical of influenza

Fever, respiratory symptoms (i.e cough, sore throat, nasal congestion), general malaise, muscle aches (myalgia), headache - which is associated with the acute phase of influenza infection and are part of what makes the flu distinct from a common cold 

The type-specific antigen (A, B, or C) of influenza viruses is found on which viral constituent?

Nucleocapsid

Which of the following statements concerning antigenic drift in influenza viruses is correct?

It results in point shifts that cause different viruses to be made to combat the different changes.

What are the principal reservoir types for the antigenic shift variants of influenza virus?

Birds (especially aquatic birds = swans, ducks, geese), pigs, humans 

What occurs when two different influenza A strains infect the same host (often pigs or birds), allowing genetic reassortment of HA and NA segments, causing new subtypes that can jump to humans and cause pandemics.

Antigenic shift 

What subtype of influenza A caused the spanish flu and in what year?

H1N1 in the year 1918 (deadliest pandemic during WW1)

What subtype of influenza A caused the Asian flu and in what year?

H2N2 and in the year 1957 - caused by antigenic shift introducing a new HA and NA combination

H3N2 caused what flu in the year 1968?

The Hong Kong Flu (another antigenic shift event leading to a global outbreak)

What strain appeared in 1997 that jumped directly from birds to humans, raising pandemic concerns?

H5N1 (causing the Hong Kong outbreak)

Which of the following infectious agents is most likely to cause a pandemic?

Influenza A virus 

A 4-year-old boy develops an acute febrile illness. His pediatrician diagnoses mumps. The organ most commonly exhibiting signs of mumps is the

Parotid glands

A 2-month-old infant developed a respiratory illness that the pediatrician diagnosed as bronchiolitis. The most likely cause of the disease is

Respiratory syncytial virus

Several paramyxoviruses can cause pneumonia in infants or children. For which of the following paramyxoviruses is there an effective vaccine available that would prevent pneumonia?

Measles virus (is a live attenuated vaccine)

Which of the following paramyxoviruses has an HN surface glycoprotein lacking hemagglutinin activity?

Respiratory syncytial virus 

Which one of the following is the best evidence on which to base a decisive diagnosis of acute mumps disease?

A fourfold rise in antibody titer to mumps antigen

Which of the following statements is more likely to be true of measles (rubeola) than German measles (rubella)?

Koplik spots are present 

A previously healthy 3-year-old boy develops a classic viral childhood illness. Which of the following primary viral infections of childhood is usually symptomatic?

Varicella-zoster virus (VZV)

Herpes zoster is likely to respond to which drugs?

Acyclovir by inhibiting DNA polymerase (Herpes is a DNA virus)

Which of the following viruses causes a mononucleosis-like syndrome and is excreted in the urine?

cytomegalovirus

Which of the following tumors is caused by a virus other than Epstein-Barr virus?

Kaposi sarcoma

The most common congenital infection is caused by

cytomegalovirus

Viruses in general have a size equivalent to this part of a eukaryotic cell

Ribosome

Mutagenic viruses often are characterized by having which of the following

reverse transcriptase

Cowpox vaccination works against smallpox because

The viral infective genome part is mostly constant

Influenza group

Orthomyxovirus (a negative sense ssRNA virus and Helical shape)

What groups of influenza causes epidemics?

Influenza A and B (because they cause seasonal epidemics)

Why is influenza A the most dangerous?

Because it has 15 HA (hemagglutinin) and 9 NA (neuraminidase) subtypes and can reassort genes two strains infect the same host (i.e. bird + human virus)

What is the difference between an epidemic and a pandemic?

epidemic = localized, regular (10-20% population infected yearly)

pandemic = global, rare, and caused by major antigenic changes (shift)

What are the characteristics of influenza B?

• Only infects humans 

• little diversity because there is only one form of HA and NA

• Lacks and M2 protein

• is NOT inhibited by antiviral drugs: amantidine and rimantidine

• Only mutates through antigenic drift 

Lab Diagnosis of HIV is NOT possible using which of the following

Detectable plasma DNA

The antiviral therapeutic agent ______ inhibits ____ by inhibiting uncoating

amantiadine and influenza

The antiviral therapeutic agent ______ inhibits ____ by inhibiting DNA polymerase

acyclovir and Herpes simple/Zoster

The antiviral therapeutic agent ______ inhibits ____ by inhibiting DNA polymerase

gangcyclovir and cytomegalovirus (CMV)

The antiviral therapeutic agent ______ inhibits ____ by inhibiting viral enzyme

Ribavirin and Respiratory syncytial

The antiviral therapeutic agent ______ inhibits ____ by inhibiting reverse transcriptase

Azidothymidine and HIV

The antiviral therapeutic agent ______ inhibits ____ by inhibiting protein synthesis

interferon and cytomegalovirus (CMV)

RNA viruses start out as single-stranded RNA (ssRNA) in the _____

cytoplasm

What are the naked Icosehedral +ssRNA viruses?

Calici

Hepe

Reo (a ds RNA virus)

Picorna 

Hepatitis E virus group?

Hepe a naked +ssRNA virus that is icosehedral in shape

Hepatitis A virus and polio group?

Picorna, a naked +ssRNA virus (icosehedral in shape)

What are the enveloped +sense ssRNA viruses (icosehedral)?

Corona

Retro

Flavi

Toga

What are the helical, enveloped, -sense ssRNA virus?

Bunya

Arena

Delta

Paramyxo

Rabdo

Orthomyxo

Filo

Measles (Rubeolla), RSV, and parainfluenza group?

Paramyxo

DNA viruses tend to have ______ shape as well as ___ sense and are double stranded within the _____

icosehedral, positive, NUCLEUS

What are the naked, icosehedral, positive sense dsDNA viruses?

Parvo (ssDNA that is helical shaped)

Adeno

Papilloma

Polyoma

What are the enveloped, icosehedral, positive sense dsDNA viruses?

Hepadna

Herpex

Pox (located in the cytoplasm)

Which of the following viruses causes a maculopapular rash and is highly contagious, with a single serotype and no animal reservoir?

Measles (Rubeola) virus

Which herpesvirus is associated with oral hairy leukoplakia and Burkitt’s lymphoma?

HHV-4

Which of the following is true about Rubella?

It is associated with congenital defects if infection occurs early in pregnancy

_HHV-1___ corresponds to a specific virus, which is ____

Herpes Simplex Virus (HSV-1)

__HHV-2__ corresponds to a specific virus, which is ____

Herpes Simplex virus 2 (HSV-2)

__HHV-3__ corresponds to a specific virus, which is ____

Varicella Zoster Virus (VZV)

HHV-4 corresponds to a specific virus, which is ____

Epstein Barr Virus (EBV)

HHV-5 corresponds to a specific virus, which is ____

Cytomegalovirus (CMV)

HHV-6/7 corresponds to a specific virus, which is ____

Roseola Virus

HHV-8 corresponds to a specific virus, which is ____

Kaposi’s Sarcoma-associated Herpesvirus

Which of the following statements about HIV latency is TRUE?

HIV persists in long-lived resting CD4+ memory T cells

Which of the following is a valid concern related to vaccine safety as discussed in the PowerPoint?

Thimerosal, a preservative containing mercury, was removed from most pediatric vaccines.

Which of the following detection methods is correctly matched with what it detects?

Western Blot → Detects viral protein

Which of the following vaccine types is correctly matched with its description?

Recombinant vaccine → Contains viral subunits produced by engineered cells

Which antiviral drug is correctly matched with its mechanism of action?

Amantadine → Inhibits viral uncoating

Which of the following statements is true?

Live attenuated vaccines contain weakened viruses that can still replicate.

Which of the following best describes the RNA World hypothesis?

RNA was likely the first genetic material, and its high mutation rate helps it adapt quickly