Chapter 13: Virus and Prions Flashcards

Question

Describe the chemical and physical structure of both an enveloped and a non-enveloped virus.

Answer 1

ENVELOPED: in some viruses, the capsid is covered by an envelope, which chemically, usually consists of some combination of lipids, proteins, and carbs. In most cases, the envelop contains proteins determined by the viral nucleic acid and materials derived from normal host cell componants. Structurally, the enveloped virus consists of the nucleic acid>>Capsomeres>> Envelop>>Spikes(on some enveloped viruses). NONENVELOPED are viruses whose capsids are not covered by an envelope. The capsid protect the viruses from nuclease enzymes in biological fluids and promotes the viruses attachment to susceptible host cells.

Answer 2

A group of viruses sharing the same genetic info and ecological niche

Answer 3

A complete, fully developed viral particle complete, infective form of a virus outside a host cell, with a core of RNA or DNA and a capsid.

Answer 4

A clearing in a bacterial lawn resulting from lysis by phage

Answer 5

Bacteriophages can be grown either in suspensions of bacteria in liquid media or in bacterial cultures on solid media. A viral plaque is a visible structure formed within a cell culture, such as bacterial cultures within some nutrient medium (e.g. agar). The bacteriophage viruses replicate and spread, thus generating regions of cell destructions known as plaques

Answer 6

Common name: common cold virus Genus: Rhinovirus Family: Picornaviridae

Answer 7

-DNA, enveloped -Transmitted through infected secretion (ex. Through sexual contact) -Hallmark characteristic of latency -Recurrence or reactivation -Dx: viral cell culture*- most accurate, takes weeks, antigen testing, nucleic acid amplification test (NAAT)- PCR

Answer 8

-The initial infection occurs in 3-5 yrs children and symptoms include cold sores or fever blisters. The virus then moves up the trigeminal nerve where it remains latent in the sensor ganglia of the nerve -Becomes latent in trigeminal nerve (along cheek)- symptoms go away -in herpesviridae family

Answer 9

-Genital herpes -Transmission: sexual and perinatal -Men more symptoms than women -Dx: PCR (NAAT)- if thought to spread to CNS, brain scan; DFA test- rapid antigen; viral culture -Herpes Encephalitis (Rare) -Latency in sacral nerves -Acyclovir lessens symptoms -Neonatal Herpes -Acquired during passage of fetus through birth canal or transplacental (congenital) -TORCH test panel for pregnant antibodies to HSV in mom’s serum; PCR test -Chicken pox (Herpes Varicella) -Signs and symptoms: fever, itchy vesicular rash -Dx: rash- vesicles- viral cultures, antibody Titer, PCR test if believed to have spread to CNS, serological test for IgM (acute) and IgG (chronic infection)- indirect ELISA or IFA test -Very contagious -Transmission: droplets, close contact, perinatal -Treatment: Acyclovir- not a cure -Latency in nerve cells -Prevention: vaccine -Is the result of an initial infection w/ herpes varicella (DNA, enveloped) -Causes pus-filled vesicles confined to face, through trunk -Herpes zoster- shingles -Signs and symptoms: burning, stinging, vesicular rash- one side of body -Transmission: same as chickenpox -Dx: same as chicken pox -Treatment: Acyclovir- not a cure -Prevention; Shingrix vaccine -Reactivation of latent varicella-zoster virus due to stress, lower immunity -Postherpetic neuralgia (chronic pain) -Herpes Zoster Ophthalmicus -Cytomegalovirus (HHV5)- cells swell -Immunocompromised susceptible -Latent in white blood cells -Transmission: saliva and bodily fluids; congenital route- virus cross placenta and affect fetus -Dx: viral cells culture- CPE- inclusions- granules containing viral infection, serology (quickest) for antigen-urine or antibody- blood serum, PCR -Treatment: Acyclovir -CMV diseases -Congenital Cytomegaly- may result in still born- TORCH test on mother -Retinitis- va impairment -Immunocompromised- AIDS pt’s -Pneumonia - apart of herpesviridae

Answer 10

-Epstein-Barr virus -Transmission: saliva -Signs and symptoms: swollen lymph nodes, fatigue, swollen spleen, sore throat, photophobia, malaise, fever -Dx: monoslide test- heterophile antibodies: serology- screening test, specific antibody to Epstein-Barr virus required (IgM or IgG), DNA Assays available- reference lab -self-limiting, supportive therapy- steroids- reduce inflammation -Atypical lymphocytes- infects B-cells, becomes latent -apart of Herpesviridae family

Answer 11

Fever, hepatomegaly (enlarged liver), abdominal pain, rash, fever, joint pain/inflammation, low WBC count

Answer 12

-in Hepadnaviridae family -pathogen: orthohepadnavirus -double stranded, Enveloped, DNA virus, spikes -Transmission: blood/body fluids, sexual, perinatal, parenteral- puncture -instead of replicating its DNA directly, it passes through an intermediate RNA stage resembling a retrovirus. -Carriers- secondary test- test (+) for surface antigen (HBsAg) -Also make antibodies to the virus -Dx: cannot be cultured, serological testing- detect HBsAg or antibodies to virus -Dane particle (complete HBV)- virion- complete viral infection particle -Envelope- where Hep B surface antigen is located (HBsAg) -Incubation period: 26 days -Chronic liver damage - could develop cirrhosis or liver cancer -Could be latency- liver cells -Could persist -Treatment: antiviral agents: Alpha interferon -Given in combo w/ other antivirals -Severe: liver transplant -Prevention: vaccine- actual virus is not used in this vaccine -produced by S. cerevisiae that carries hepatitis-virus gene on plasmid -has reverse transcriptase -complication: cancer -signs and symptoms: yellowing of the eyes, abdominal pain, and dark urine

Answer 13

-of Picornaviridae family- RNA -single-stranded RNS, nonenveloped -Transmission: direct contact/droplets; indirect contact- fomite -Dx: signs and symptoms, viral culture -Replicated in nasal cavity -Signs and symptoms: runny nose and eyes, no fever, cough -Treatment: otc med: aspirin; rest, fluids -prevention: handwashing, social distancing

Answer 14

-Single-stranded RNA, enveloped - of Coronaviridae family -Colds -SARS -MERS-CoV -Covid-19 (SARS-CoV-2) -cytopathic effects: syncytia, cilia shrinkage, altered junctions between cells -High mutation rate -Signs and symptoms range from minor to life-threatening -Transmission primarily droplets or aerosols -Dx: rapid antigen or antibody tests; PCR test amplifies and detects viral RNA -Treatment: Predesivir or Convalescent Plasma -Prevention: vaccine- RNA based- can still get the disease, but symptoms less severe; masks -Transmission: droplets -RNA core -Hollow cylinder capsid -S-protein for attachment

Answer 15

-of Flaviviridae family -single-stranded RNA, enveloped -Incubation period- 22 days -Transmission: same as HBV, more often through parenteral routes (IV drug use); rare- blood transfusion -Chronic liver damage- cirrhosis (worse w/ Hep C) -Necrosis -Signs and symptoms: same as Hep B -Dx: PCR for viral RNA (antibodies for HCV) -Treatment: drug combinations (Peginterferon), liver transplant -Prevention: no vaccine (due to rapid mutation), PPE -Can be cured when viral RNA antibodies not found by medicine standards -Viral persistence

Answer 16

-“Transmission”: Coninfected w/ Hep B -single-stranded RNA, enveloped -Similar to HBV in Transmission -Prevention: Hep B vaccine- some protection -family: Deltaviridae -Enveloped, RNA virus -genus: delta virus -treatment: Pegylated interferon alpha

Answer 17

-Orthomyxoviridae -A: found in different animals, including ducks, chickens, pigs, whales, horses, and seals -Transmission: droplets, close contact (direct), indirect contract- fomites -Common Nov.-March -HA spike (hemagglutinin spike for attachment to host) -NA spike (neuraminidase (breaks down mucin (in mucous)) spike for viral assembly and release) -Variation in H and N antigens -Mutation of spikes- cannot get immunity from getting disease -Orthomyxoviruses -Influenza virus- RNA, enveloped -The 3 types of influenza: A, B, and C -Are distinguished by their matrix protein -Orthomyxoirus Viral Genome -An antigen drift occurs when the genome gradually changes to avoid host antibody -An Antigenic shift occurs when influenza A acquires a new HA or NA gene; major genetic reassortment among different strains -c: cause a mild respiratory illness and are not thought to cause epidemics

Answer 18

-Lab dx: antigen detection- nasal washes/nasal swabs, viral culture, NAAT (PCR) -Oseltamivir (neuraminidase inhibitors), Zanamivir (neuraminidase inhibitors- stop virus from getting assembled and released), newer antiviral agents -Prevention: vaccine -Signs and symptoms: fever and symptoms of common cold -Envelope hemagglutinin spikes (H spike- cause RBCs to clump, and allows for attachment (HA spike)) -seasonal epidemics

Answer 19

-Lentivirus includes -Human Immunodeficiency Virus destroys helper CD4 T cells -Use reverse transcriptase to produce DNA from viral genome -HIV attachment and replication in T cell -Transmission: blood and body fluids, sexual, perinatal (across placenta or through birth canal), blood transfusion (uncommon) -Multiplication of a Retrovirus 1) Attachment via glycoprotein spikes 2) Then enters through diffusion 3) Uncoating 4) Reverse transcriptase- enzyme? 5) Latency as a provirus -Latency: genome of virus in chromosome 6) Biosynthesis- replicate 7) budding -Stages of HIV infection -Phase 1: swollen lymph nodes (3 yrs into disease) -Phase 2: fever, swollen lymph nodes, counts increasing in helper T cell? -Phase 3: (8-10) CD4 count: low, susceptible to opportunistic infection: ex. TB, pneumonia -Dx methods -HIV antibodies by ELISA and Western blotting -ELISA for detection of P24 (protein coat) antigen -ctyopathic effects: destruction of T cells

Answer 20

-Fusion inhibitors- block entry -Reverse Transcriptase inhibitor- AZT -Integrase inhibitor -Protease inhibitor- block maturation

Answer 21

-Combos of nucleoside reverse transcriptase inhibitors -Non-nucleoside reverse transicpase inbitor of protease inhibitor

Answer 22

-Treatments of viral infections -Nucleoside analogs -Acyclovir: herpes virus -(HAART) Zidovudine (AZT): HIV -Other Antivirals -Enzyme inhibitors- neuraminidase inhibitors: influenza, AIDS (RT inhibitors, protease inhibitors, integrase inhibitors, AIDS- fusion inhibitor) -Alpha-interferon: viral hepatitis

Answer 23

-Prions-infectious proteins that are self-replicating -Proteinaceous infectious particles -Inherited and transmissible by ingestion (of meat- deer, food), corneal transplants, and surgical instruments for brain and eye surgery -causes spongiform encephalopathies (brain becomes spongy-like, holes; no treatments, results in death (ex. Mad cow disease/bovine spongiform disease) in animals and humans -eliminated by incineration

Answer 24

Changes shaped- pleaded- abnormal- scrapie protein PrPSc

Answer 25

-Signs and Symptoms: Memory loss, impaired sensed, rhythmic muscle contractions -Prion-caused disease in humans -eventually causes dementia and death

Answer 26

1) In living animals- animals are infected with virus and observed. 2) In embryonated eggs- Hole is drilled in the shell of the embryonated egg and a viral suspension is injected in the fluid of the egg. Viral growth is indicated by the death of the embryo or embryo cell damage. 3) In cell cultures- cells grown in culture media in the lab

Answer 27

-Western blotting- virus's reaction to antibodies -PCR -RFLP (restriction fragment length polymorphisms

Answer 28

1) Attachment: Phage attaches to host cell 2) Penetration: Phage penetrates host cell and injects its DNA 3) Biosynthesis: Phage DNA directs synthesis of viral components by the host cell 4) Maturation: Viral components are assembled into virions 5) Release: Host cell lyses and new visions are released

Answer 29

Describe the lysogenic cycle of bacteriophage lambda 1) Phage attaches to host cell and injects DNA 2) Phage DNA circularizes and enters lysogenic cycle. 3) Phage DNA integrates within the bacterial chromosome by recombination, becoming a prophage. 4) Lysogenic bacterium reproduces normally. 5) Many cell divisions. 6) Occasionally, the prophage may excise from the bacterial chromosome by another recombination event, initiating a lytic cycle

Answer 30

DNA: 1) Attachment- virion attaches to host cell. 2) Entry and Uncoating- virion enters cell, and its DNA is uncoated. 3) A portion of viral DNA is transcribed, producing mRNA that encodes early viral proteins. 4) Biosynthesis- Viral DNA is replicated, and some viral proteins are made. 5) Late translation: Capside proteins are synthesized. 6) Maturation- virions mature. 7) Release- virions are released. RNA: 1) Attachment 2) Entry and uncoating- ssRNA: + or sense strand, ssRNA: - or antisense strand, dsRNA: + or sense strand with - or antisense strand 3) RNA replication by viral RNA-dependent RNA polymerase. 4) Translation and synthesis of viral proteins 5) Maturation and release.

Answer 31

-pathogen: rubivirus -family: matonaviridae -transmission: respiratory route, aerosol -signs and symptoms: red rash (less extensive than measles, and shorter recovery time) light fever, -prevention: vaccine -treatment: none -complications: rare but can cause encephalitis in adults

Answer 32

-pathogen: Orthopneumovirus -Pneumoviridae family -single-stranded RNA, enveloped -causes cell fusion when grown in cell culture -signs and symptoms: mild cold-like symptoms, but can cause life-threatening pneumonia in very young infants or older adults, coughing, wheezing, fever only in cases of bacterial complications -sometimes implicated in cases of otitis media -dx: serological tests and rt-PCR- samples of respiratory secretions to detect both antibodies and the virus -treatment: Riboviran and Palivizumab -transmission: direct contact and droplets -prevention: vaccine for older adults and and very young infants, handwashing

Answer 33

-prevention: vaccine- 15mo old -pathogen: orthorubulavirus -family: paramyxoviridae -single-stranded RNA, enveloped -targets parotid glands -signs and symptoms: painful swelling of one of both parotid glands, fever, pain when swallowing -transmission: saliva, respiratory secretions -viremia (presence of virus in the blood) begins several days before onset of mumps symptoms and before the virus appears in saliva -complications: hearing loss, meningitis, inflammation of ovaries or testes, pancreatitis -treatment: rest, advil or Tylenol for pain

Answer 34

-pathogen: morbilivirus -family: Paramyxoviridae -single-stranded RNA, enveloped -cytopathic effects: cell fusion -complications: rare form of encephalitis- acute sclerosing panencephalitis (SSPE), middle ear infections, pneumonia, and secondary bacterial infections. -once acquired, immunity is lifelong -prevention: vaccine -transmission: respiratory route -signs and symptoms: macular lesions appear on the skin, and Koplik’s spots appear on the oral mucosa. -treatment: otc fever reducers

Answer 35

-pathogen: orthopoxvirus -family: poxviridae -double-stranded DNA, enveloped -first disease to be artificially induced and first to be eradicated from human pop -transmission: aerosol -signs and symptoms: pustules that may be nearly confluent on skin -treatment: none

Answer 36

-Pathogen: varicellovirus -prevention: vaccine -transmission: aerosol -treatment: acyclovir -signs and symptoms: fever, blisters, red spots, fatigue, itching

Answer 37

-single-stranded RNA, noneveloped -prevention: vaccine -people can be carriers w/o developing illness -pathogen: hepatovirus -grown in cell culture -viremia eventually occurs and spreads to liver, kidneys, spleen -transmission: fecal-oral -signs and symptoms: yellowing of skin and eyes, dark urine, enlarged, tender liver -treatment: self-eliminating

Answer 38

-pathogen: orthohepevirus -transmission: fecal-oral -does not cause chronic liver disease, but is responsible for mortality rate in excess of 20% during pregnancy -lack of appetite, nausea, and jaundice -prevention: vaccine, handwashing -treatment: none

Answer 39

-double-stranded DNA, nonenveloped -family: reoviridae -signs and symptoms: low grade fever, diarrhea, vomitting -transmission: fecal-oral -prevention: vaccine, handwashing -treatment: none

Answer 40

Antigenic drift refers to the gradual accumulation of small mutations in the genes encoding the surface proteins (hemagglutinin (HA) and neuraminidase (NA)) of influenza viruses, leading to minor changes in the virus's structure.

Answer 41

Antigenic shift is a more dramatic change that occurs when influenza A viruses swap their genetic material, resulting in new combinations of HA and/or NA proteins that the population has not seen before.

Answer 42

-transmission: fecal-oral (from food and water) or aerosols (from vomiting) -prevention: handwashing -signs and symptoms: diarrhea, vomiting -dx: PCR -treatment: none

Answer 43

-reservoir: humans -signs and symptoms: fatigue, fever, muscle weakness -complications: paralysis, death -transmission: fecal-oral -prevention: vaccine -treatment: NSAIDS relieves pain

Answer 44

-pathogen: lyssavirus -family: filoviridae -signs and symptoms: fever, headache, excess salivation, muscle spasms, paralysis, and mental confusion. -prevention: vaccine -transmission: saliva of infected animals -treatment: blood transfusions and antivirals

Answer 45

-common herpesvirus that infects humans and other primates. -transmission: direct contact, sexual activity, mother-to-child (cross placenta, or during birthing process), blood transfusion -prevention: none -signs and symptoms: -healthy adults: Fever Sore throat Fatigue Muscle aches Swollen lymph nodes -newborns: Hearing loss Vision problems Developmental delays Seizures Liver and spleen enlargement Pneumonia -immunocompromised: High fever Seizures Brain inflammation Retinitis (inflammation of the retina) Lung disease Gastrointestinal problems -treatment: ganciclovir or valganciclovir