Microbiology - Block 1 - Part 1

davidwurbel7's version from 2015-06-01 13:11

Flow Chart

Question Answer
RNA>Positive (+) Sense>Naked>CCalici
RNA>Positive (+) Sense>Naked>HHepe
RNA>Positive (+) Sense>Naked>RReo
RNA>Positive (+) Sense>Naked>PPicorno
RNA>Positive (+) Sense>Enveloped>CCorona
RNA>Positive (+) Sense>Enveloped>FFlavi
RNA>Positive (+) Sense>Enveloped>TToga
RNA>Positive (+) Sense>Enveloped>RRetro
RNA>Negative (-) Sense>Enveloped>BBunya
RNA>Negative (-) Sense>Enveloped>AArena
RNA>Negative (-) Sense>Enveloped>DDelta
RNA>Negative (-) Sense>Enveloped>PParamyxo
RNA>Negative (-) Sense>Enveloped>RRhado
RNA>Negative (-) Sense>Enveloped>OOrthomyxo
RNA>Negative (-) Sense>Enveloped>FFilo
Parvo B19Parvo
JC, BKPolyoma
HSV, VZV, CMV, EBV, HHV6 & 8Herpes
Hep BHepadna
Small pox, Molluscum contagiousumPox
Norwalk (Noro)Calici
Hep EHepe
Polio, Entero, Rhino, Coxsackie, Hep A,Picorno
Coronavirus, SARS?Corona
HepC+ Arbo (Dengue, Yellow Fever)Flavi
Rubella+ Arbo (West Nile, EEV,WEEVToga
Hep D virusDelta
Measles, Mumps, RSV, ParainfluenzaParamyxo


Question Answer
Viral envelope the coats the virion is derived fromHost Cellular Membrane
What step in the viral infection cycle determines what cell type the virus infectsAttachment
What is tropismSpecific Cell Type Infected
Early genes are required for production ofNonstructural Proteins
Late genes are required for production ofStructural Proteins
Nonstructural proteins areEnzymes
Structural proteins areCapsid and Glycoproteins
Pulls off host membrane to become enveloped virionBudding
Lysis of host cell resulting in non-enveloped (naked) virionLytic
Virus that undergoes budding is an ________ virionEnveloped
Virus that undergoes lytic phase is a ________ virionNon-enveloped (Naked)
Virions in the bloodViremia
Viremia is required for development ofVaccine
Bacteria in the bloodBactermia
Substance that stops translation in the infected cellInterferon
A giant multi-nucleated cell formed by fusion of a virally infected cell with a new cellSyncytia
An intracellular compartment composed of manipulated membrane and new viral components that stains denselyInclusion Bodies
Microbes that cause congenital if acquired in uteroTORCHeS Complex
Formation of cancer cellsOngogenic
Direct destruction of cellsLytic or acute
(Insert each of the TORCHeS complex)

Types of Infections

Question Answer
viral infection remains constant – N.A. and virions are presentChronic Persistent
viral remains “silent” and hides out in cell. – N.A. only are presentChronic Latent
Type of infection in which virus is cleared due to immune responsesTransient
Type of infection in which virus is not cleared; immune response may be fully activeChronic
Chronic infection in which infectious virus is continuously presentPersistent
Chronic infection in which the virus genome is present in cells but not infectious virionsLatent
Chronic infection in which a latent infection that reactivates and yields infectious virus before becoming latent (non-replicating) againRecurrent
A chronic persistent infection with a prolonged incubation period of months to years and in which the disease symptoms progressively worsen to deathSlow Viral


Question Answer
The paramount cell of the immune responseCD4 Helper T Cell 1
NK cell detects viral infected cells by absence ofMHC I
First response to infectionInterferon-alpha
Second response to infectionNK Cells

Naked DNA Viruses

Question Answer
Naked icosahedral dsDNA, Low Risk- Types 1, 4, 6, 11, High risk - 16 and 18; Pathogenesis proteins alter cell cycle control E6 inhibits p53 and E7 inhibits Rb. Diagnosis Warts - hyperkeratosis Cervical – Koilocytic cells on Pap smearHPV
Naked dsDNA. Ubiquitous but only cause disease in immuno-compromised.Human Polyomaviruses
Naked dsDNA. Causes PML in immune-compromised JCV
Naked dsDNA. Causes renal disease in immune-compromisedBKV
Speech, vision, coordination, mental status, or a combination of these functions is impaired, followed by paralysis of the arms and legs and finally deathPML
Renal dysfunction, Painful urination, Lower back pain, HematuriaBKV Hemorrhagic Cystitis
Naked dsDNA with fiber spikes Fibers are cytotoxic. Basophilic intranuclear inclusions. Transmission through poorly chlorinated swimming pool and fomites Children (pools) and military. Pharyngoconjuctivits is unique Live vaccine (4/7/21) for militaryAdenovirus
Smallest Naked ssDNA virusParvovirus B19
Targets erythroid cells leading to anemiaParvovirus B19
Slapped-cheek rash in children, Acute polyarthritis in adults, Aplastic crisis in patients with chronic hemolytic anemia, Hydrops fetalis in pregnant womenParvovirus B19
Transmitted by respiratory droplets with vertical transmission (mother -> fetus)Parvovirus B19
At risk elementary school age children, pregnant women, people with chronic anemiaParvovirus B19
Replicates in erythroid precursor cells and disrupts erythropoiesisParvovirus B19
Erythematous macular rash may spread to exposed skin, arms, legs & trunk in lacy pattern & subsides after initial cheek rashParvovirus B19

Enveloped DNA Viruses

Question Answer
Large dsDNA enveloped linear with Icosohedral capsidHerpes Family
Establish lytic, persistent, latent and recurrent infectionsHerpes Family
Establishes latency in trigeminal gangliaHSV 1
Establishes latency in sacral gangliaHSV 2
Painful vesicular lesions with fever and general malaiseHSV 1 and 2
Treatment with AcyclovirHSV 1 and 2
Cowdry type A inclusion bodies in the nuclear membraneHSV 1 and 2
Fever and headache; Destruction of the temporal lobe (Usually left); Erythrocytes in the cerebrospinal fluid; Seizures; Focal neurologic abnormalities (personality changes)Herpes Meningo-Encephalitis
Most common cause of infectious corneal blindness in USAHerpetic Keratitis HSV-1
Establishes infection through cuts in the skin of the fingers; Occurs in nurses or physicians and thumb-sucking childrenHerpetic Whitlow
The body establishes infection through cuts or abrasions in the skin usually around the ear and jaw; Sometimes acquired during wrestling or rugbyHerpes Gladiatorum
Lab diagnosis cowdry nuclear inclusion plus syncytiaHSV 1 and 2
Establishes latency in the dorsal root gangliaVaricella-Zoster (VZV)
Secondary infection in a "belt" around lower chest/abdomen with extremeVaricella-Zoster (VZV)
Live attenuated vaccine containing a large doseVaricella-Zoster (VZV)
Painful, vesicular lesions over the trunk and scalpVaricella-Zoster (VZV)
Usually seen 5-9 years. Highly infectious. Initial infection via direct contact or aerosols. Common in childhood ~60% sero-positive by 18yrsChicken Pox
Usually seen > 60 years; Re-activation of dormant VZV virus; Associated with age-related immunosuppression; Rash is localized to thoracic dermatome; Extreme pain due to nerve damage before and during and afterShingles
Vesicle progression - Asynchronistic puritic rash -> macular > papular > vesicles > pustules > crustChicken Pox
Aspirin should not be given to children with chicken pox due to the possibility ofReye Syndrome
Enveloped dsDNA that targets muco-epithelial and B cellsEBV
Establishes latent infection B cells and can immortalize B cellsEBV
Lymphocytosis and Atypical Lymphocytic Downey cells (T cells)EBV
Heterophile positive infectious mononucleosisEBV
Fever and general malaise; Sore throat with white patches; Swollen lymph nodes; Hepato-splenomegaly; Rash can be seen sometimes on the trunk; Heterophile Positive infectious mononucleousEBV
Monospot/Heterophilic Antibody Test in which heterophile antibodies agglutinates with horse RBC (Indicative, but can be leukemia, lymphoma)EBV
Anti-VCA (Viral Capsid Antigen) IgM is definitive forEVB (Initial)
Anti-EBNA (Ebstein Barr Nuclear Antigen)IgG indicates past infection but not activeEVB (Past Infection)
Complications include Oral hairy leukoplakia, CNS lymphoma, Hodgkins lymphoma, Burkitt Lymphoma (Central Africa), Nasopharyngeal cancer (China)EBV
Complication of EBV commonly seen in AIDS patientsKaposi Sarcoma Herpes Virus KSHV / HHV-8
Enveloped dsDNA that targets mononuclear (T cell, macrophage) with possible transmission from mom to fetus and also from transplantationCytomegalovirus CMV
The C in TORCHeSCytomegalovirus CMV
Most common in utero infection in USCID = Cytomegalo-Inclusion Disease
Petachiae; Jaundice; Hepato-splenomegaly; Thrombocytopenia; “Blue berry muffin baby”Cytomegalovirus CMV
Diagnosis by observation of Owl eye intranuclear inclusion with halo with giant cytoplasm PCRCytomegalovirus CMV
Treatment for CMVGancicylovir
Fever and general malaise; Sore throat with white patches; Hepato-splenomegaly, Heterophile Negative infectious mononucleosisCytomegalovirus CMV
Heterophile Negative infectious mononucleosisCytomegalovirus CMV
Usually <2 year old; Sudden high fever with “fits”; Lacy rose-red uniform maculo-papular rash 2 days after disappearance of feverRoseola infantum
Enveloped Complex dsDNA; Linear dsDNA; Large Enveloped Complex; Replicates in cytoplasmSmall Pox
Fever and general malaise followed by; Painful maculo-papular lesionsSmall Pox
Guarnieri bodies intracytosplamic inclusionsSmall Pox
Attenuated vaccinia strainSmall Pox
Rash begins in the mouth and spreads to the face, arms & legs, hands & feet and can cover the entire body with in 24 hrs; Rash is synchronousSmall Pox
Enveloped complex DNA virus; Very common and benign in children; Increasing in sexually active & immunocompromised personsMolluscum Contagiosum
Raised nodular to wart-like tumors on the skin; Umblicated nodules (2-10 mm) have a central caseous plug that can be squeezed out; Occur in cluster of 5-20 nodules; In immunocompromised can be in clusters of 100sMolluscum Contagiosum
Molluscum bodies - Abundant eosinophilic cytoplasm (accumulated virions), and a small peripheral nucleusMolluscum Contagiosum

RNA Viruses

Question Answer
An RNA with the same base sequence as the mRNA; Equivalent to “sense” RNAPositive (+) Polarity
An RNA with sequence that is complementary to the mRNA; Equivalent to “anti-sense” RNANegative (-) Polarity
(+)RNA serves as template for synthesis of (-)RNARNA dependent RNA polymerase (RDRP)
Example of +ssRNA virusRhino Virus
Example of -ssRNA virusInfluenza
The virion particle carries its own RNA dependent RNA polymerase to be able to convert (-) RNA strand to (+)strand mRNA-ssRNA virus

Naked +RNA Viruses

Question Answer
dsRNA Naked double capsidRotavirus
Transmission is fecal-oral; Infantile gastroenteritis (watery diarrhea); Most common cause of diarrhea in <2yrs old; Affects 18 millions infants & children & about 1 million deaths (w/o vaccine)Rotavirus
Two vaccines in the form of VP7 Subunit and attenuated vaccine, Both vaccines are oral vaccinesRotavirus
Presents in infants & small children (< 5 years old); Gastroenteritis- vomiting and watery diarrhea, low grade fever with abdominal pain; No blood or leukocytes in stool (differential for bacterial infection); Loss of fluids and electrolytes can cause severe dehydrationHyperactive bowel sounds, Sunken eyes, Decreased skin turgor, Dry mucosa, Abnormal tachycardia, Decreased urine outputRotavirus
Prevention: Good hand-washing practicesRotavirus
Naked ss (+) RNANorwalk (Noro) Virus
Transmission is fecal-oral; Affects all ages usually cruise ships and restaurantsNorwalk (Noro) Virus
Presents as acute gastroenteritisNorwalk (Noro) Virus
Naked, icosahedral capsid and single-stranded (+) RNA genomePicornaviridae Family
Family of viruses that includes rhinovirus and enteroviruses (Poliovirus, Coxsackie A virus, Coxsackie B virus, Echovirus and Hepatitis A virus)Picornaviridae Family
Single stranded RNA genome of positive polarity (+ssRNA)Rhino Virus
Most common cause of the coldRhino Virus
Targets respiratory epithelial cells with no treatment or vaccineRhinovirus
Point mutations in the genome of the virus that cause a change in the protein capsid (antigen) that the immune system cannot recognizeAntigenic Drift
Clinical presentation Incubation period - 2-3 days; Symptoms usually last approximately a week; Sneezing & rhinorrhea (runny nose) (clear); Mucus secretion; Nasal obstruction; Mild sore throat, Cough, Headache; Fever is usually low grade, if any.Rhinovirus
Naked ss(+)RNA; Acid stable thus can survive in the GI tract; Associated with a seasonal incidence (summer/autumn); Transmitted primarily by the fecal-oral route or respiratory droplets; Controlled primarily through hand-washingEnterovirus
(Insert Presentation 9, slide 12)
Question Answer
Targets respiratory and/or GI epithelial (tropism is serotype specific)Enterovirus
Aseptic or “sterile” meningitisEnterovirus
Picornaviridae; sub-group Enterovirus; Naked ss (+) RNA; Travels to CNS; asymmetric atropy; Salk inactivated IPV (USA); Sabin oral attenuated OPV (WHO), Transmission by fecal-contaminated water common sourcePoliovirus
(Insert Presentation 9, slides 18 and 19)
Question Answer
Acute hemorrhagic conjunctivitis- pain, edema, photophobia, foreign body sensation, fever, malaise, and headacheCoxsackie A
Fever, lesion on mouth and tongue FIRST. Then appears on the hands & feet 1-2 days later. Complication: dehydrationCoxsackievirus A
Pleurodynia (feeling of tightness around the chest), Myocarditis & pericarditis, PancreatitisCoxsackie B
Fever, chest pain, cyanosis ; Myocardial cell necrosis and damage to conduction bundle EKG changes and arrhythmia. Myocardium becomes flabby > Heart failure > death; Biopsy of the myocardium is done when viral myocarditis is suspected - Reveals lymphocytic (T cells) infiltrate (diagnostic) and Necrosis of myocardial cellsCoxsackie B Myocarditis
Common cause of aseptic meningitisEchovirus
"O" of the TORCHeSOther (Enterovirus)