MLT-240 Quiz 5 Ch. 29-Virology

What is the correct sequence of viral infection of naked viruses? Select one: a.Attachment, penetration, replication, cell lysis b.Penetration, attachment, replication, cell lysis c.Replication, penetration, attachment, cell lysis d.Penetration, replication, attachment, cell lysis

a. Attachment, penetration, replication, cell lysis The virus first attaches to the host cell through interaction with viral adhesions and host cell receptor molecules. Next, the genome penetrates into the host cell. Once in the host cell, the virus uses the host cell machinery to replicate itself. Once replication is complete and the new viruses are assembled, the cell is lysed to release the new viruses.

Presence of this HBV serologic marker indicates a person is highly infectious. a. HBs antigen b. HBc antigen c. Anti-HBs d. Anti-HBc

a. HBs antigen When HBV is replicating, significant amounts of HBs is produced. Presence of this antigen in serum indicates a highly infectious state. Presence of HBe antigen is also an indicator of infectivity; however, due to a mutation some HBVs do not produce HBe.

What virus causes immune suppression in the host by targeting and destroying the host's CD4+ T cells? a. HIV b. Hepatitis B c. Epstein-Barr d. CMV

a. HIV HIV is known to destroy CD4+ T cells. Hepatitis B causes disease in liver cells, not white blood cells. The EBV and CMV show depressed T-cell or antibody responses to other unassociated antigens.

Which virus has been linked to Kaposi sarcoma? a. Human herpesvirus 8 b. CMV c. Herpes simplex d. Epstein-Barr

a. Human herpesvirus 8 Human herpesvirus 8, also referred to as Kaposi sarcoma virus, is associated the Kaposi sarcoma. This cancer occurs primarily in immunosuppressed individuals, such as those suffering from acquired immunodeficiency syndrome (AIDS). Before the AIDS epidemic, the cancer was seen most frequently in persons over 60 years of age.

Which of the following is the best description of a primary cell culture? a. It is a culture where tissue is removed from an animal, arranged in a monolayer, and in which very little cell division occurs. b. It is a culture which contains cells that can divide, but passage is limited to 50 generations. c. It contains cells with a variable number of chromosomes and can be subcultured indefinitely. d. This describes the only cells the specimen will be plated on.

a. It is a culture where tissue is removed from an animal, arranged in a monolayer, and in which very little cell division occurs. Primary cell cultures are obtained from tissue removed from an animal. The tissue is finely minced and then treated with an enzyme such as trypsin to disperse further individual cells. The cells are then seeded onto a surface to form a monolayer. With primary cell lines, only minimal cell division occurs.

What infectious agent causes Creutzfeldt-Jakob disease, Kuru, and "mad cow" disease? a. Prion b. Bacteria c. Virus d. Parasite

a. Prion Prions, proteinaceous infectious particles, cause a group of disease in mammals called TSEs. Examples of TSEs include Kuru and Creutzfeldt-Jakob disease in humans, scrapie in sheep, bovine spongiform encephalopathy (BSE, or mad cow disease) in cattle, and chronic wasting disease in elk.

What is the most common virus isolated from infants with lower respiratory infections and causes croup, bronchitis, bronchiolitis, and interstitial pneumonia? a. RSV b. Adenovirus c. Rotavirus d. Norovirus

a. RSV RSV is the most common virus isolated from infants with lower respiratory tract infections and causes croup, bronchitis, bronchiolitis, and interstitial pneumonia.

What virus is the most common cause of viral gastroenteritis in infants and children? a. Rotavirus b. Influenza virus c. Enterovirus d. RSV

a. Rotavirus Rotaviruses are the most common cause of viral gastroenteritis in infants and children.

What virus causes Hantavirus pulmonary syndrome? a. Sin Nombre virus b. Dobrava virus c. Junin d. Lassa

a. Sin Nombre virus The virus found in mice and caused an outbreak in the four-corner states of the US was characterized as a new Hantavirus; it was named Sin Nombre ("no name") virus. The disease caused by this virus is now known as Hantavirus pulmonary syndrome.

What requirements do viruses have for replication? a. They must be inside a living cell. b. They must be in an environment where all the necessary amino acids are present. c. They can use a dead cell to replicate. d. They require dead, decaying flesh so that all amino acids and enzymes are present.

a. They must be inside a living cell. Viruses are obligate intracellular parasites, meaning they must be inside a living cell to replicate. They are not capable of self-replication but force the host cell to carry out the replication process.

Severe acute respiratory syndrome (SARS) is caused by a a. coronavirus. b. picornavirus. c. enterovirus. d. paramyxovirus.

a. coronavirus. SARS is caused by coronaviruses. SARS is characterized by high fever, pneumonia, and a mortality rate of about 10%. Besides SARS, coronaviruses cause about 15% of all coldlike infections and a small number of cases of gastroenteritis.

The classic example of a bite-wound infection is a. rabies. b. varicella zoster. c. infectious mononucleosus. d. Ebola virus.

a. rabies. Rabies is produced as a result of a bite from a rabid animal. S. aureus can produce severe skin infections, but it is usually not the result of a bite. The plague is an arthropod-transmitted disease. Ebola virus is transmitted by blood and body fluid contact.

What virus causes immune suppression in the host by targeting and destroying the host's CD4+ T cells? Select one: a.HIV b.Hepatitis B c.Epstein-Barr d.CMV

a.HIV HIV is known to destroy CD4+ T cells. Hepatitis B causes disease in liver cells, not white blood cells. The EBV and CMV show depressed T-cell or antibody responses to other unassociated antigens.

What viral genus causes rabies? Select one: a.Lyssavirus b.Lassa virus c.Marburg virus d.Calicivirus

a.Lyssavirus Rabies is caused by several strains of viruses belonging to the genus Lyssavirus.

What virus is the most common cause of viral gastroenteritis in infants and children? Select one: a.Rotavirus b.Influenza virus c.Enterovirus d.RSV

a.Rotavirus Rotaviruses are the most common cause of viral gastroenteritis in infants and children.

Complications of Epstein-Barr virus (EBV) infection include all the following, except Select one: a.acute glomerulonephritis. b.Reye's syndrome. c.thrombocytopenia purpura with hemolytic anemia. d.splenic hemorrhage and rupture.

a.acute glomerulonephritis. Complications of EBV infections are splenic hemorrhage and rupture, hepatitis, thrombocytopenia purpura with hemolytic anemia, Reye's syndrome, encephalitis, and other neurologic syndromes.

Which serologic marker would be expected to be found in the serum of someone successfully vaccinated against hepatitis B virus (HBV)? a. Anti-HBe b. Anti-HBs c. Anti-HBc d. Anti-HDV

b. Anti-HBs The vaccine for HBV is HBs antigen. Successful vaccination leads to formation of anti-HBs. Presence of this antibody indicates immunity to HBV infection.

How is hepatitis B transmitted? a. Contaminated food and water b. Blood and body fluids c. Respiratory droplets d. Airborne

b. Blood and body fluids The HBV was discovered as early as 1965 and was originally named Australian antigen, because it was first diagnosed in an Australian man. The blood of an infected patient is infectious; the disease can also be sexually transmitted.

Which hepatitis virus is spread by the fecal-oral route? a. Hepatitis B b. Hepatitis A c. Hepatitis C d. Hepatitis D

b. Hepatitis A The hepatitis A virus is generally spread by the fecal-oral route and by food handlers and children.

Which of the following describes a diploid cell culture that is not a primary culture? a. It is a culture where tissue is removed from an animal, forms a monolayer, and very little cell division occurs. b. It is a culture of cells that can divide, but passage is limited to about 50 generations. c. Cells often have variable numbers of chromosomes and can be subcultured indefinitely. d. This describes the only cells the specimen will be plated on.

b. It is a culture of cells that can divide, but passage is limited to about 50 generations. Diploid cell cultures can divide, but passage is limited to about 50 generations. With increasing passage, diploid cells become more insensitive to viral infection.

What virus is the most common cause of arboviral encephalitis in the world? a. Ebola virus b. Japanese encephalitis (JE) virus c. Venezuelan equine encephalitis virus d. Eastern equine encephalitis virus

b. Japanese encephalitis (JE) virus JE virus is a major cause of encephalitis in Asia and is the most common cause of arboviral encephalitis in the world.

Which of the following describes cytopathic effects seen in viral culture? a. The way viruses kill the infected host cell b. The visual changes produced in an infected cell by a virus c. The tears that the virus puts in an infected host cell's membrane d. The way the virus lyses the infected cell after all the new virus particles are formed and ready to be released.

b. The visual changes produced in an infected cell by a virus Many viruses produce characteristic visual changes in infected cells, referred to as cytopathic effect.

Adenoviruses produce all the following types of infections, except a. acute hemorrhagic cystitis. b. meningitis. c. acute respiratory distress. d. epidemic keratoconjunctivitis.

b. meningitis. Although half of all adenovirus infections are asymptomatic, the virus causes about 10% of all pneumonia and 5% to 15% of all gastroenteritis in children. The virus causes upper respiratory tract infections, acute respiratory distress, epidemic keratoconjunctivitis, acute hemorrhagic cystitis, and pharyngoconjunctival fever.

How is hepatitis B transmitted? Select one: a.Contaminated food and water b.Blood and body fluids c.Respiratory droplets d.Airborne

b.Blood and body fluids The HBV was discovered as early as 1965 and was originally named Australian antigen, because it was first diagnosed in an Australian man. The blood of an infected patient is infectious; the disease can also be sexually transmitted.

Which cancer is associated with EBV? Select one: a.Hepatocellular carcinoma b.Burkitt's lymphoma c.Non-Hodgkin's lymphoma d.T-cell leukemia

b.Burkitt's lymphoma EBV has been associated with some cancers, including Burkitt's lymphoma and nasopharyngeal carcinoma. Burkitt's lymphoma is a malignant disease of the lymphoid tissue seen most commonly in African children.

What is the composition of viral transport media? Select one: a.Amies medium with charcoal b.Isotonic buffered saline with protein c.Cary-Blair d.Cooked meat broth

b.Isotonic buffered saline with protein Several viral transport systems are commercially available. Most transport media consist of buffered isotonic solution with a protein, such as albumin, gelatin, or serum, to protect less stable viruses

What is a prion? a. Protein subunit of a viral capsid b. Uncovered infectious RNA molecule c. A proteinaceous infectious particle d. A lipopolysaccharide infectious particle

c. A proteinaceous infectious particle Prions, proteinaceous infectious particles, cause a group of diseases in mammals called transmissible spongiform encephalopathies (TSEs).

Which of the following is the description of continuous cell cultures? a. It is a culture where tissue is removed from an animal, forms a monolayer, and in which very little cell division occurs. b. It is a cell culture that can divide, but passage is limited to 50 generations. c. Cells often have variable numbers of chromosomes and can be subcultured indefinitely. d. This describes the only cells the specimen will be plated on.

c. Cells often have variable numbers of chromosomes and can be subcultured indefinitely. Continuous cell cultures have variable numbers of chromosomes and are capable of indefinite passage. Continuous cell lines are heteroploid, meaning they have an abnormal and a variable number of chromosomes that are not a multiple of the normal haploid number.

What disease does the varicella zoster virus (VZV) cause? a. Mumps b. Genital warts c. Chickenpox d. Rubella

c. Chickenpox VZV, in the genus Varicellovirus, spreads by droplet inhalation or direct contact with infectious lesions. The virus causes two different clinical manifestations: varicella (chickenpox) and zoster (shingles).

Which hepatitis virus commonly leads to chronic hepatitis and cirrhosis, often requiring a liver transplant, and causes a high risk for development of liver cancer? a. Hepatitis A b. Hepatitis D c. Hepatitis C d. Hepatitis E

c. Hepatitis C Many patients with hepatitis C virus infection are asymptomatic. However, even asymptomatic cases can progress to chronic hepatitis and cirrhosis, ultimately requiring a liver transplant. Both hepatitis B and hepatitis C viruses have been associated with liver cancer.

Which virus is a bloodborne pathogen? a. Hepatitis A virus b. Rabies virus c. Hepatitis C virus d. Norovirus

c. Hepatitis C virus Hepatitis C is spread through blood and blood products. Hepatitis A virus is spread the fecal-oral route.

What is the most common flavivirus infection in the United States? a. West Nile virus b. Eastern equine encephalitis virus c. St. Louis encephalitis (SLE) d. Rocky Mountain spotted fever

c. St. Louis encephalitis (SLE) In the United States, the most common flavivirus is SLE. Since the mid-1970s, an average of about 100 cases of SLE has been reported annually in the United States.

The cytopathic effect demonstrating intranuclear inclusions is associated with a. influenza virus. b. respiratory syncytial virus (RSV). c. cytomegalovirus (CMV). d. rotavirus.

c. cytomegalovirus (CMV). Intranuclear inclusion with a perinuclear halo is referred to as owl's eye and is a characteristic cytopathic effect associated with CMV. CMV normally produces mild or asymptomatic primary infections in immunocompetent adults.

All the following methods are used by the laboratory to diagnose viral infections, except a. nucleic acid amplification. b. direct detection. c. growth on artificial media. d. serologic assays

c. growth on artificial media. The laboratory uses three major methods to diagnose viral infections: direct detection of the virus in the clinical specimens (antigen detection or nucleic acid amplification), isolation of the virus in cell monolayers, and serologic assays to detect viral antibodies.

What is an unsuitable storage temperature for viruses because it allows the development of ice crystals? Select one: a.4° C b.-10° C c.-20° C d.-70° C

c.-20° C Specimens for viral isolation should not be stored at ?2-20° C. This temperature facilitates the formation of ice crystals, which disrupts the host cells and results in significant loss of viral viability.

What disease does the varicella zoster virus (VZV) cause? Select one: a.Mumps b.Genital warts c.Chickenpox d.Rubella

c.Chickenpox VZV, in the genus Varicellovirus, spreads by droplet inhalation or direct contact with infectious lesions. The virus causes two different clinical manifestations: varicella (chickenpox) and zoster (shingles).

What virus causes genital herpes? Select one: a.Human herpesvirus 6 b.CMV c.Herpes simplex virus type 2 d.Human herpesvirus

c.Herpes simplex virus type 2 Genital herpes are usually caused by HSV-2, although HSV-1 can cause as many as one third of the infections.

When is the best time to collect a specimen for culture from a patient suspected of having a viral disease? Select one: a.1 week after onset of symptoms b.5 days after onset of symptoms c.Less than 3 days after onset of symptoms d.2 weeks after onset of symptoms

c.Less than 3 days after onset of symptoms Viral shedding is usually greatest during the early stages of infection, so the best specimens are those collected as early as possible. The sensitivity of viral culture may decrease rapidly 3 days after onset of symptoms.

What virus is the major cause of the common cold? Select one: a.Rotavirus b.RSV c.Rhinovirus d.Norovirus

c.Rhinovirus Rhinoviruses are the major cause of the common cold.

What is the most common flavivirus infection in the United States? Select one: a.West Nile virus b.Eastern equine encephalitis virus c.St. Louis encephalitis (SLE) d.Rocky Mountain spotted fever

c.St. Louis encephalitis (SLE) In the United States, the most common flavivirus is SLE. Since the mid-1970s, an average of about 100 cases of SLE has been reported annually in the United States.

What type of genome do herpesviruses have? Select one: a.ssDNA b.ssRNA c.dsDNA d.Both dsDNA and ssRNA

c.dsDNA The herpesviruses have a genome of linear dsDNA, an icosahedral capsid, an amorphous integument surrounding the capsid, and an outer envelope.

The genome of a virus is composed of? a. single-stranded DNA. b. RNA. c. double-stranded DNA. d. Any of the above

d. Any of the above At a minimum, viruses contain a viral genome of either RNA or DNA and a protein coat—the capsid. The genome can be either double-stranded (ds) or single-stranded (ss).

All of the following are identifiable viral agents of gastroenteritis, except a. Norwalk. b. rotavirus. c. enteric adenoviruses. d. CMV.

d. CMV. The most important identifiable agents of viral gastroenteritis are human rotaviruses, enteric adenoviruses, caliciviruses, Norwalk virus, and Norwalk-like viruses.

What type of cancer is associated with human papilloma virus (HPV)? a. Lung b. Ovarian c. Skin d. Cervical

d. Cervical Although associated with the common wart, some HPV types are associated with cancer, including cervical cancer.

Which one of the following viruses causes a viral hemorrhagic fever? a. Sin Nombre virus b. Venezuelan equine encephalitis virus c. Rhabdovirus d. Ebola virus

d. Ebola virus Causes of viral hemorrhagic fever include Ebola, Marburg, dengue, Lassa, and several others. These agents are found primarily in the tropics and can have a significant mortality rate.

What virus causes the measles? a. Mumps b. RSV c. Herpes virus 6 d. Rubeola virus

d. Rubeola virus The measles (rubeola) virus is an enveloped virus classified in the genus Morbillivirus.

What are giant multinucleated cells formed from cell fusion as a result of viral infection? a. Giant cells b. Macrophages c. Glial cells d. Syncytia

d. Syncytia Syncytia are giant multinucleated cells formed from cell fusion as a result of virus infection. RSV can produce a classic syncytial formation in HEp2 cells or monkey kidney cells.

Poliovirus is transmitted primarily by a. aerosol. b. blood. c. urine. d. fecal-oral.

d. fecal-oral. Poliovirus, a member of the enteroviruses, is transmitted by the fecal-oral route. Polio is rare in most countries due to effective vaccination programs.

The noroviruses are most noted for producing a. upper respiratory tract infections. b. lower respiratory tract infections. c. meningitis. d. gastroenteritis.

d. gastroenteritis. Noroviruses and sapoviruses are members of the family Caliciviridae and cause gastroenteritis in humans. Noroviruses are the most common cause of infectious gastroenteritis in the United States.

Symptomatic congenital infection with CMV includes all the following symptoms, except a. hepatosplenomegaly. b. microcephaly. c. chorioretinitis. d. meningitis.

d. meningitis. Congenital infections and infections in immunocompromised patients are often symptomatic and can be serious. Symptomatic congenital infection is characterized by petechiae, hepatosplenomegaly, microcephaly, and chorioretinitis.

Infection with CMV in nonimmune pregnant women can cause a. misshapen limbs. b. congenital heart defects. c. liver problems. d. microencephalopathy.

d. microencephalopathy. CMV, a herpesvirus, can be found in almost all body fluids. The virus can cross the placenta and may be transfused in blood and blood products. Nonpregnant women should be concerned about potential damage to the fetus, such as cerebral malformation (microencephalopathy) and necrosis of brain tissue.

The most common route of infection of laboratory workers with HBV and HIV is a. mucous membranes. b. inhalation. c. ingestion. d. needlestick.

d. needlestick. HBV and HIV are bloodborne pathogens that are transmitted through exposure to blood and body fluids. Although infection through the mucous membranes has occurred, the most common route of infection of health care workers is through needlesticks where the organisms are introduced into the bloodstream.

What type of cancer is associated with human papilloma virus (HPV)? Select one: a.Lung b.Ovarian c.Skin d.Cervical

d.Cervical Although associated with the common wart, some HPV types are associated with cancer, including cervical cancer.

Which one of the following viruses causes a viral hemorrhagic fever? Select one: a.Sin Nombre virus b.Venezuelan equine encephalitis virus c.Rhabdovirus d.Ebola virus

d.Ebola virus Causes of viral hemorrhagic fever include Ebola, Marburg, dengue, Lassa, and several others. These agents are found primarily in the tropics and can have a significant mortality rate

Which of the following is true of the virus that causes AIDS? Select one: a.dsDNA genome b.Present in a number of animal reservoirs c.Preferentially infects liver tissue d.Human retrovirus

d.Human retrovirus Human immunodeficiency virus (HIV) causes AIDS. The viral genome is ssRNA and replicates using an RNA-DNA hybrid. Replication relies on the enzyme reverse transcriptase, making the virus a member of the human retroviruses.

What virus causes the measles? Select one: a.Mumps b.RSV c.Herpes virus 6 d.Rubeola virus

d.Rubeola virus The measles (rubeola) virus is an enveloped virus classified in the genus Morbillivirus.

The most common route of infection of laboratory workers with HBV and HIV is Select one: a.mucous membranes. b.inhalation. c.ingestion. d.needlestick.

d.needlestick. HBV and HIV are bloodborne pathogens that are transmitted through exposure to blood and body fluids. Although infection through the mucous membranes has occurred, the most common route of infection of health care workers is through needlesticks where the organisms are introduced into the bloodstream.