– RNA viruses – Flashcards
Unlock all answers in this set
Unlock answers| negative sense RNA viruses |
all are helical all are enveloped, ether sensitive all carry RdRp in particle transcription first step mRNA complementary to genome |
| examples of one rna segment - sense rna viruses |
rhabdoviridae paramyxoviridae filoviridae |
| example of two rna segment - sense rna viruses |
| arenaviridae |
| examples of three rna segment - sense rna viruses |
| bunyaviridae |
| examples of eight rna segment - sense rna viruses |
| orthomyxoviridae |
| what does negative sense RNA viruses carry |
carry a RNA genome with no open reading frame virus particle carries a RdRp |
| Rabies (rhabdoviridae) structure and biology |
- RNA non-segmented, bullet shaped particle multiples in muscle cells at the NMJ enters the peripheral nervous system total neuronal dissemination posterior horns of spinal cord, cortex, midbrain, basal ganglia, and medulla damaged from CNS throught automonic nerves reaches salivary gland no viremia |
| where does rabies replicate exclusively |
| gray matter |
| where is the virus found in the highest concentration |
| in the hippocampus |
| rabies epidemiology and disease |
slow virus, only one serotype bite of a rabid animal not transmitted by mosquitoes 1-3 months of incubation period fever, headache, nausea, vomiting, pain at bite site, confusion, hallucination CNS disease almost always fatal encephalitis |
| rabies encephalitis |
hyperexcitability aggression convulsion hydrophobia (swallowing leads to pain) gradually spreading pareses coma, death |
| detection of rabies encephalitis |
no viremia negribodies- cytoplasmic inclusion bodies in hippocampus and spinal cord (pathognonomic) immunoflourescent examination of infected brain of rabid animal for viral antigen |
| vaccine for rabies encephalitis |
killed virus vaccine for high risk people (animal handlers) rabies IgG and killed vaccine to people bitten by rabid animals long incubation period after infection, allows vaccination effective domestic cats, and dogs to be vaccinated |
| vaccine for rabies |
killed virus vaccine for high risk people (animal handlers) rabies IgG and killed vaccine to people bitten by rabid animals long incubation period after infection, allows vaccination effective domestic cats and dogs to be vaccinated |
| paramyxoviridae |
eneveloped, one segement of -RNA antigentically stable, single serotype HN F protein production of protease by host |
| f protein |
mediates membrane fusion initiaties virus infection+spread of virus to cells
|
| how is f protein synthesized |
| as an inactive precursor |
| how is f protein activated |
| by cleavage of (F1, F2) S-S link |
| what do all paramyxoviruses possess |
fusion activity cause syncytia formation |
| parainfluenza 1 |
major cause acute croup (laryngotracheobronchitis) in infants URI in adults and children occurs during fall months |
| parainfluenza-2 |
URI occasionally LRI |
| parainfluenza 3 |
| second major viral cause of sever LRI in children, pneumonia, and brochiolotis |
| respiratory syncytial virus (RSV) |
number one cause of LRI and bronchiolitis, pneumonia in infants below 2 years important cause of otitis media no viremia no hemagglutinin or neuraminidase activities posses F protein, and a G protein ribavirin nasal spray |
| mumps |
transmission by large droplets (sneezing) virus in saliva and urine acute contagious disease |
| where does mumps initial replicate? |
| respiratory mucosa |
| where does viremia in mumps disseminates? |
| parotid gland |
| what can mumps cause |
pancreatitis nonsuppurative enlargement of parotid gland, testis, ovaries asceptic meningitis meningoencephalitis |
| what is orchitis |
| inflammation of testis |
| what is oophoritis |
| inflammation of ovaries |
| what is the only host for mumps |
| humans |
| measles pathogenesis |
droplet infection oropharynx replication in respiratory tract regional lymph nodes primary viremia virus spread to reticuloendothelial system virus replication viremia II dissememination to skin, urinary tract and CNS |
| where does the rash for measles appear |
first on the face and then descends to trunk and extremities disappears in the same sequence |
| respiratory symptoms of measles |
coryza, hacking cough, conjunctivitis multinucleated giant cells koplik's spots |
| kopliks spots |
small, bluish white ulceration on the buccal mucosa oppostie to lower molars contain viral antigens in cytoplasm and nucleus multinucleated cells |
| sequence of events during measle infection |
viremia respiratory symptoms kopliks spots rashes encephalitis SSPE |
| complications of measles infection |
interstitial giant cell pneumonia acute postinfectious encephalitis subacute sclerosing panencephalitis (SSPE) |
| interstitial giant cell pneumonia |
leukocyte infilteration of bronchial and alveolar walls fusion of epithelial cells syncytia |
| acute postinfectious encephalitis |
one week after appearance of rash autoimmune reaction against brain tissue meningeal irritation CSF contains measles antibodies |
| subacute sclerosing panencephalitis |
generally affects children develops many years after measles infection viral inclusion in brain cells measles RNA found no infectious virions produced CSF contains measles antibodies |
| filoviridae |
marburg, ebola viruses one - sense RNA segment monkeys can function as reservoirs highly virulent viruses (P4 pathogen) transmitted by contact and respiratory route cause African Hemmorrhagic Fevers hemorrhage in many body orificies |
| Arenaviridae (ROBO) |
two segments of - RNA also ambisense coding strategy helical nucleocapsid |
| Lymphocytic Chorimeningitis (LCMV) |
persistent infection in mice arenavirus viremia vertical spread to offsprings aseptic meningitis in humans |
| Lassa Fever |
extremely virulent P4 west africa viremia ribavirin treatment |
| how is Lassa Fever transmitted |
mice airborne or excrement of mice |
| what type of infection is Lassa Fever |
| persistent |
| what does Lassa Fever cause |
vomiting/Diarrhea carditis hepatitis encephalopathy |
| argentine hemmorrhagic fever |
junin virus viremia mouse transmission |
| bolivian hemorrhagic fever |
machupo virus viremia, transmitted by mouse |
| bunyaviridae |
contains 3 - sense RNA segments most of the members are transmitted by insects helical nucleocapsid, enveloped most of them are insect transmitted |
| examples of bunyaviridae |
la crosse encephalitis virus california encephalitis virus rift valley fever crimean congo hemorrhagic fever hantaan virus |
| hantaan virus |
hemorrhagic fever with renal syndrome hantavirus pulmonary syndrome (HVPS) transmitted by deer mouse respiratory route of transmission no insect vector virus excreted in urine and feces viremia, no man to man transmission ribavirin treatment |
| orthomyxoviridae (influenza) |
enveloped, - sense RNA, segmented 8 RNAs in Flu A ; B 7 RNAs if Flu C two glycoproteins: HA, NA nucleocapsid protein (N), matrix protein (M) subtypes of influenza based on variation in HA ( 3 types), NA (2 types) |
| which flu has no NA |
| Flu C |
| what is responsible for antigenic variation in influenza |
| NA and HA |
| what is the basis for A, B, C classification for the Flu |
nucleocapsid protein matrix protein |
| hemagglutinin |
oligomerized to trimers cleaved into HA1 HA2 by extracellular proteases held by disulfide bonds has a globular and stalk part |
| why is cleavage important in hemagglutinin |
| important for infectivity (fusion) not binding to cells |
| what is the purpose of the globular part of HA |
| neutralizing antibodies, antigenic variation |
| what is the purpose of the stalk part of HA |
membrane anchor part responsible for fusion activity |
| where are the extracellular proteases that cleave HA found |
| respiratory tract |
| NA |
tetramer on surface of envelope removes sialic acid residues on glycoproteins facilitates release of viral particle |
| antigenic drift |
minor change in HA/NA genes occurs slowly over years few nucleotide alterations by error prone viral polymerase can occur both in flu A and B |
| antigenic shift |
major change in HA/NA occurs rapidly within a given season genome reassortment (animal/human) only in Flu A no flu B or C viruses that infects animals |
| influenza replication |
sialic acid receptor for HA virus uncoats in the cytoplasm nucleocapsid reaches the nucleus viral RNA polymerase cus the host nascent mRNA at the 5' end 5' RNA pieces are used as primers for Flu transcription (mRNA synthesis) cap snatching, cannibalization mechanism only rna virus with a nuclear replicative cycle and splicing during transcription |
| what inhbits flu transcription |
| AcD |
| how is the flu spread |
| aerosal (droplets) |
| what are some symptoms of flu |
chills, headache, dry cough, muscle pain, malaise, anorexia, coryza myocarditis, encephalitis |
| what bacteria is the respiratory tract now suspectible to with the flu |
| H. influenzae, S. pneumonia, and S. aureus |
| what affects the spread of influenza virus |
| anti-NA antibodies |
| how is influenza treated |
amantadine/rimantidine neuraminidase inhibitors |
| amantadine/rimantidine |
anti flu a block viral uncoating in the cytoplasm, probably through M2 protein resistant mutants map M2 protein |
| when do you use neuramindase inhibitors |
| against both flu a and flu b |
| reyes syndrome |
acute encephalopathy of children and adolescents progressive mental retardation fatty degeneratio of Liver influenza A, B, and VZV association exacerbated by salicylates |
| Guillain-Barre Syndrome |
an immune complex disease CNS disorder, acute demyelinating neuropathy associated with swine influenza vaccination inflammation of peripheral nerves leading to paralysis associated with complicated CMV, EBV infection hepatitis may also occur |
| reoviridae |
non-enveloped, icosahedral nucleocapsid 10 segments of dsRNA dsRNA specific RNA polymerase mostly infect animals model system cause respiratory and gastrointestinal infection in rodents no known human disease |
| rotavirus a |
11 dsRNA segments oral fecal route of transmission number one cause of infantile diarrhea rotovirus b causese diarrhea in adults |
| colorado tick fever virus |
12 dsRNA segments transmittd by Ticks causes rashes and similar clinical picture as that of rocky mountain spotted fever |
