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89 Cards in this Set
- Front
- Back
What are viruses?
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Viruses are Strict Intracellular Parasites that:
- Replicate only within a host cell - Cannot synthesize their own ATP - Multiply by entering host cell, uses the host’s machinery to synthesize their own components. . |
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What are the 5 characteristics of a virus?
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1. Smallest of infectious agents
20-300 nm in diameter 2. Not seen with light microscope Most important – Single type of nucleic acid 3. Virion= complete viral particle. DNA or RNA, not both. 4. Protein coat = Lipoprotein envelope. 5. “Naked virus” No envelope |
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Can you recall the parts of the structure of a virus?
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1. Nucleoprotein: Nucleic Acid (DNA or RNA)
2. Capsid= complete shell Capsid also called “protein coat” 3. 2 typical shapes: icosahedral or helical |
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Can you recall the structure of the Icosahedral Adenovirus?
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Adenovirus
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Do you remember the structure of the Icosahedral Herpes virus?
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Herpes virus
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Name a helical virus that contains a lipidmembrane and glycoprotein.
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Ebola Virus
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Name a helical virus that has a Tabacco Mosaic.
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Rabies virus
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Can you recall what the Virus infectious cycle looks like?
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Name the 6 stages of the Virus infectious cycle.
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1. Attachment
2. Absorption/ Penetration 3. Uncoating 4. Synthesis 5. Assembly Release |
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How are virus transmitted?
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Transmitted person to person
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When does viral disease dissipate?
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Viral Disease dissipates after immune response.
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Name a condition due to viral infections that causes a marked increase in lymphocytes?
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Lymphocytosis
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What are the steps of replication in viral DNA?
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1. In the Nucleus
2. Usually icosahedral symmetry 3. Usually double stranded DNA |
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How do viruses replicate in RNA?
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1. in the Cytoplasm
(Exception Retroviruses in nucleus) 2. Usually helical symmetry 3.Usually single strand RNA 4. Enveloped |
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Name 3 Viral infection sites.
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1. Respiratory
2. Enteric 3. Urinary Tract |
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The following organisms are suspected in what type of infections? (slide # 12 in viruses handout)
Adenovirus, flu, Paraflu,RSV, Rhinovirus |
Respiratory
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The following organisms are suspected in what type of infections?
Rotavirus, Enterovirus, Enteric (40,41), Aseptic meningitis, Adenovirus |
Enteric
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The following organisms are suspected in what type of infections?
CMV, Mumps, Rubella, Measles, Adenovirus |
Urinary Tract
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Name 3 other viral infection sites.
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1. Skin, Mucous Membrane, Lesions
2. Sterile Fluids 3. Blood |
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Name the infection site associated with the following organisms.
Enterovirus, HSV, VZV, CMV |
Skin, mucous membranes and lesions.
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Name the infection site associated with the following organisms.
Enterovirus, HSV, flu, CMV |
Sterile fluids
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Name the infection site associated with the following organisms.
CMV, HSV, VZV, Enterovirus, Adenovirus |
Blood
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Name 5 methods of viral detection.
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1. Culture:
- conventional tube cultures - shell vials 2. Rapid Direct Antigen Immunofluorescence 3. Cytomegalovirus antigenemia 4. Serology 5. Nucleic Acid Sequencing- PCR |
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Define Cytopathic effects or (CPE).
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Characteristic changes to cell morphology caused by the viral particle releasing the host cell.
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How are cytopathic effects detected?
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Simply, what is seen in the tissue cells under light microscope
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What is required for detection of Cytopathic effects?
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Depends on virus and cell line inoculated, specimen source, and rate of growth
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What does rounding, syncytia or none mean in identifying cytopathic effects?
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Rounding = ?
Syncytia = when cells fuse together to make one large cell. None = no changes to the cells due to the virus. |
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What is Confirmation? (slide # 16 in the handout)
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Confirmation: fix a scraping from culture tube on a slide, stain with a monoclonal Ab (IFA).
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What type of stain is this and what type of virus?
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Immunoflouresce Parainfluenzae
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What type of staining is this and what is the name of the organism?
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CMV
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What type of staining is this and what is the name of the organism?
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VZV
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What type of staining is this and what is the name of the organism?
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immunoflouresence and HSV
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Name 3 DNA viruses.
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1. Adenoviridae
2. Herpesviridae - HSV, VZV, CMV, EBV 3. Papovaviridae - Papillomavirus |
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Name 3 characteristics of the Adenoviridae virus.
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1. - double stranded DNA
2. - lacks envelope 3. - 60-90 nm, icosahedral symmetry |
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What is the pathogenesis/clinical findings of Adenoviridae?
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- Infect the eye, respiratory, GI, & urinary tracts
- Predominantly in winter - Transmission- close physical contact. |
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What diseases are caused by Adenoviridae? (slide # 20)
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Diseases:
conjunctivitis, upper/lower respiratory infections and gastroenteritis |
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How can Adenoviridae be recovered?
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May be recovered from stool, body fluids, rectal and conjunctival swabs.
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Which virus has the ability to establish lifelong persistent infections.
- undergo periodic reactivation. |
Herpesviridae or Herpes Virus
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HSV 1 & 2, VZV, CMV, EBV are all different types of which virus?
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Herpes viruses- 120-200 nm in diameter, icosahedral, enveloped and double stranded DNA. (slide # 21)
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non-genital route
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HSV 1
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Transmitted sexually
Mother infects newborn during birth |
HSV 2
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Both infect epithelial cells and establish latent infections. Most frequently isolated virus in lab.
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HSV 1 & 2
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chicken pox is caused by...?
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Varicella Zoster virus
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Shingles is caused by....?
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Herpes Zoster
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What is this disease called?
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Chicken pox or Varicella Zoster Virus
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What is this disease called?
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Shingles or Herpes Zoster
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These two viruses may be confused with HSV- both recovered from skin lesions.
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1. Varicella Zoster virus: chicken pox
2. Herpes Zoster: shingles (slide # 23) |
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This Virus:
1. Replicates in respiratory tract, salivary glands, and kidneys. 2. life-threatening infections in immunocompromised. 3. Widespread in humans and animals by close contact with a carrier. 4. Can be spread through the placenta, blood transfusions, organ transplantation, and breast milk. |
Cytomegalovirus (CMV)
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This virus:
1.Causes acute infectious mononucleosis 2. Contributes to Burkitt's lymphoma and nasopharyngeal carcinoma 3. Extremely difficult to isolate 4. Diagnosed by serological IgM and IgG tests |
Ebstein-Barr virus (EBV)
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This virus:
1. 45-55 nm, icosahedral symmetry, no envelope, double stranded 2. All papovaviruses may be considered DNA tumor producing viruses 3. Causes human warts and certain serotypes of cervical cancer |
Papovaviridae (HPV)
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1. Picornavirus: Enterovirus, Rhinovirus & Hepatovirus (Hepatitis A)
2. Orthomyxoviridae: Influenza A & B 3. Paramyxoviridae: Parainfluenza, RSV, Mumps, Measles 4. Retroviridae: HIV 1 & 2 Hantavirus |
RNA viruses
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27 nm, icosahedral, single stranded
Lack envelope 5 genera: 3 discussed: Enterovirus, Rhinovirus, and Hepatovirus Enterovirus: poliovirus, coxsackievirus, echoviruses, entero viruses 68,70,71 |
Picornaviruses
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Polioviruses 1-3:
1. Enter through mouth, replicate in oral pharynx or small intestine. 2. Isolated from stool. Exposure to one of four: 1. Asymptomatic infection 2. Mild illness 3. Aseptic meningitis 4. Paralytic polio |
Pathogenesis/Clinical Findings: Enterovirus.
(Iron Lung= Enterovirus) |
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1. Divided into group A & B
2. Recovered from blood in early stages as well as throat; for up to 6 weeks Group A: herpangina; hand, foot, and mouth disease & acute hemorrhagic conjunctivitis Group B: Myocarditis, pericarditis, and meningoencephalitis |
Coxsackie viruses
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Enteric Cytopathogenic Human Orphan viruses
Cause transitory enteric infections Recovered from humans only (monkey cell culture) Cause aseptic meningitis, febrile illnesses with/without rashes, common cold |
Echoviruse
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Isolated from nose, throat, and rarely, feces
Cause URI- including common cold |
Rhinovirus
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80-120 nm, possess helical symmetry, single-stranded segmented genome, has an envelope
Influenza viruses: responsible for respiratory disease-not stomach flu |
Orthomyxoviridae
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1889 H2N2 strain
1901 H3N8 strain 1918 H1N1 strain “Spanish Flu” high morbidity and morality 1947 H1N1 strain 1957 H2N2 strain “Asian flu” high morbidity low mortality |
Influenza viruses Global Pandemics
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1968 H3N2 strain
“Hong Kong flu” high morbidity low mortality 1977 H1N1 strain 1997 H5N1 strain right now an avian influenza pandemic Experts fear a human pandemic 2009 H1N1 strain |
Influenza viruses Global Pandemics
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epidemic respiratory infections that occur during low temperatures and humidity in winter
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Influenza A & B: (slide # 36)
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chills, headache, dry cough followed by fever, muscle aches, malaise, and anorexia
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Symptoms of Influenzae A & B
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Periodically undergoes minor and major changes in its outer glycoprotein hemagglutinin and neuraminidase.
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Influenzae viruses
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antigenic drift that results in intermittent pandemics
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Influenzae: Minor mutations.
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antigenic shift that results in yearly epidemics
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Influenzae: Major Mutations
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Composed of Parainfluenza types 1, 2, and 3, mumps, measles, and respiratory syncytial virus
150-300 nm, single-stranded RNA, helical symmetry, and an envelope |
Paramyxoviridae
(slide # 38) |
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Cause severe respiratory infection
Transmission- direct contact, aerosol droplets or fomites Primary infection most severe Pathogenesis similar to influenza |
Parainfluenza
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1. Circulates in fall and winter
2. Causes severe lower respiratory infections in young children. 3. Spread from secretions by close contact 4. Enters nasal or conjunctival route |
Respiratory Syncytial Virus (RSV)
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Parotitis, may involve other organs
Transmission similar to parainfluenza Vaccine is available |
Mumps
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1. Spread by aerosol route
2. Epidemics occur in late winter & spring in temperate climates 3. Systemic infection characterized by rash 4. Vaccine is available |
Measles
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contain reverse transcriptase or RNA-dependent DNA polymerase
HIV-1 & HIV-2 100 nm, icosahedral symmetry and an envelope |
Retroviridae
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1. Causes hemorrhagic fever and pulmonary syndrome
2. Genus of the family Bunyaviridae |
Hantavirus
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1. 27-32 nm, single-stranded, spherical
=symmetry & no envelope 2. Produces sporadic, epidemic infectious = hepatitis 3. Transmitted by contaminated food/water: = fecal-oral route |
Hepatitis A: RNA
(slide # 44) |
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1. Produces acute/chronic hepatitis
- Etiological agent in hepatocellular carcinoma. 2. - 42 nm, double-stranded DNA, and an envelope - Envelope contains lipid and HBsAG- plays a role in serological identification. 3. Transmitted by parenteral, transfusion, sexual intercourse, and needles (acupuncture/tattoos) |
Hepatitis B: (DNA hepadnavirus)
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What are 4 Hepatitis B clinical findings?
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Jaundice, nausea, vomiting, fever
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What are 2 Hepatitis B laboratory findings?
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1. Serological tests used to diagnose
2. Recovery is generally unsuccessful |
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1. Small pox
2. Does not cause chicken pox 3. DNA virus that reproduces in cytoplasm |
Poxviridae
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There are 5 differential characteristics between "smallpox" and "chickenpox."
What are they? |
1.Smallpox = Orthpoxviridae
Chickenpox = Herpesviridae 2.Smallpox = Synchronous lesions Chickenpox = Asynchronous lesions 3. Smallpox = Deep lesions Chickenpox = Superficial lesions 4. Smallpox = Centrifugal spread Chickenpox = Centripetal spread 5. Smallpox = Prominent on face and palms Chickenpox = Prominent in chest |
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Rabies
Migrates over nerves Fatal encephalitis |
Rhabdoviridae
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Arthropods – mosquito
Equine encephalitis WEE- Western EE EEE- Eastern EE VEE- Venezuelan EE Rubivirus Rubella-" German measles””3-day measles” - human |
Arboviruses- RNA
(slide # 50) |
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Mosquito
St. Louis Encephalitis Yellow fever Panama canal Africa – 90% current Dengue fever “Break bone fever” West Nile virus Came to USA 1999 |
Flaviviridae
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Fever and encephalitis
California encephalitis Rift Valley Fever Hantavirus Pulmonary Syndrome four corners -1993 Hanta virus - Asia Hemorrhagic fever with renal failure |
Bunyaviridae
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Enterovirus
1. Poliovirus March of Dimes Salk – formalin-killed virus Sabin – oral vaccine, attenuated virus 2. Coxsackie Virus Respiratory, rashes 3. Echovirus Aseptic meningitis 4. Rhinovirus Common cold |
Picornaviridae
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What virus causes:
1. Common cold 2. Severe Acute Respiratory Syndrome (SARS) |
Coronaviridae
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Name 2 RNA "cold" viruses.
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Rhinovirus
and Coronaviridae |
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Which viruses cause common colds?
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Rhinovirus and
Coronaviridae (slide # 54) |
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Name 3 RNA viruses that cause Diarrhea?
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1. Norwalk virus
2. Norovirus 3. Rotavirus |
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Caused Diarrhea on cruise ships and in Superdome after hurricane Katrina.
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Norovirus
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Acute infectious diarrhea
Leading cause of infant mortality world wide |
Rotavirus
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What disease do the following viruses cause?
Filoviridae: -Ebola virus -Marburg virus Arenaviridae: -Lassa Fever virus |
Hemorrhagic fever
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