RNA (-) Viruses I Flashcards
What is the viral classification of the orthomyxovirus family?
RNA Neg SS enveloped viruses
All RNA (-) viruses bring their own
Polymerase
Orthomyxoviruses replicate in the
Nucleus
The most common cause of the flu is influenza strains
A, B, and C
Has 8 segments, meaning there is 8 places where it can mutate
Influenza
A major example of orthomyxovirus is
Influenza
Point mutations in the viral genome leading to changes in the hemagglutinin (HA) and neuraminidase (NA) molecules
Antigenic drift
What are the two major classes of influenza mutation?
Antigenic rift and antigenic shift
When segments are shared to form a new species
Antigenic Shift
Cause segment changes and Pandemics (global scale)
Antigenic shift
Influenza that causes epidemics and pandemics
Influenza A (via antigenic shift)
Influenza that causes epidemics via antigenic drift
Influenza B
A glycoprotein that binds to sialic acid found in membranes in Upper respiratory and RBCs causing them to clump
Hemeagglutinin (HA)
Define the cell tropism, i.e. cells that can be affected by influenza
HA antigens H1, H2, and H3
HA molecule will bind to sialic acid on the cell membrane. Then the virus is endocytosed into the cell. However, before uncoating, the pH must be changed by
M2 protein
Inhibit the M2 protein and thus prevent uncoating of the influenza virus
Amantadine and Rimantadine
Amantadine and rimantadine do allow increased
Dopamine release
Molecule that allowes the virus to break free from the sialic acid once it is inside the cell
Neuraminidase (NA)
NA inhibitors blocking release of virus
Oseltamivir/Anamivir (Tamiflu)
There are two types of influenza vaccine, what are they?
Killed (IM) and Live attenuated (nasal)
A common comorbidity with influenza is pneumonia caused by
Staph aureus
Caused by aspirin treatment and causing encephalitis, and hepatomegaly. Will uncouple mitochondria proton gradient along the electron transport chain in the hepatic cells
Reyes syndrome
Don’t give kids with the flu aspirin because it can cause
Reyes syndrome
What is the viral classification of the parmyxovirus family
SS Negative Sense RNA
All negative sense RNA viruses replicate in the cytoplasm. The only exception is
Orthomyxovirus
What is the live attenuated vaccine for paramyxovirus?
MMR (Measles and Mumps are paramyxovirus and Rubella is different)
What are the 4 C’s to diagnose measles?
Cough, Conjunctivitis, Coryza, Koplic sign
Blueish spots on a red background near the molars on the mucosa caused by measles
Koplic Spots
Measles comes with a fever of
104 degrees
Maculopapular rash late, starts on the head and works down. This is a clinical manifestation of
Measles
Another type of rash seen with measles is
Confluence rash
One complication of measles is
Pneumonia
If you see subacute sclerosing pan enchephalitis, look for
Anti-measles antibodies in the CSF
One virulence factor of measles is
HA
In measles, cause multinucleated giant cells found in lymphoid tissue
-Causes red inclusion bodies
Fusion proteins
What can we give to patients with measles to reduce mortality and complications?
Vitamin A
Replicates in the salivary glands
Mumps
Has the clinical manifestation of orchitis with impaired fertility and testicular atrophy
Mumps
Meningitis can also happen with
Mumps
What are the three virulence factors of mumps?
Fusion protein, HA, and NA
In babies, Mumps can cause
Respiratory Syncytial Virus (RSV)
Attaches to G protein to infect respiratory epithelial cells
Mumps
Most commonly in infants, and shows bronchiolitis and penumonia
Mumps
Causes the virulence factors to stick together in Mumps
Fusion protein
Can be used to treat mumps in adults
Ribavirion
Monoclonal IgG antibody against mumps
Palivisumab
What are the three forms of paramyxovirus?
Measles, Mumps, and Parainfluenza
Causes a seal park cough (croup)
Parainfluenza
What are the three virulence factors of parainfluenza?
NA, HA, and Fusion protein
What is the radiographic sign on x-ray that a patient has parainfluenza?
Steeple radiographic sign
What is the viral classification of the rhabdovirus?
Encapsulated Negative Sense RNA virus
The capsule for rhabdovirus looks
Bullet shaped
What is the shape of the nucleocapsid for rhabdovirus?
Helical nucleocapsid
Glycoprotein that binds to nicotinic acetocholine receptors in the membrane in the NMJ junction and will replicate there
Rhabdovirus
Intitially, rhabdovirus infects the synaptic receptors in the
Motor end plate
A popular form of rhabdovirus is
Rabies
Moves in a retrograde fashion
Rabies
Rabies replicates in
Motor neurons (dorsal roots)
Shows the clinical symptoms of encephalopathy and fever
Rabies
Diagnosis is clinical and can be confirmed with negri bodies, eosinophilic cytoplasmic inclusions found in hippocampus or cerebellum
Rabies
A characteristic feature of rabies is
Negri bodies
Shows eosiniphilic negri bodies
Rabies
Rabies infects the pyramidal cells of the
Hippocampus
Hold negri bodies together
Perkinje cells
Has an antidote w/ passive preformed antibodies IgG prior to symptoms and killed vaccine
Rabies
You should give a killed vaccine treatment even if you simply wake up with a
Bat in the room
What is the viral classification of Ebola (Filovirus)?
Enveloped Negative sense SS helical RNA virus
The RNA in ebola is
Helical RNA
A key clinical manifestation of filovirus infection is
Hemorrhagic fever and petechial rash
The end organ failure seen in filovirus infection is the death of the
Kidneys and Liver
A fatal infection
Filovirus (Ebola)
Characterized by extreme blood loss and shock
Ebola (filovirus)
What are the vectors for filovirus?
Monkeys or fruit bats
What is the viral classification of Bunyavirus?
Enveloped negative sense RNA virus
The bunya virus obtains the envelope from the
Golgi body of host cells
What is the segmentation classification of the Bunyavirus?
Segmented w/ 3 circular segments
A moquito virus that falls under bunyavirus
Arborvirus
What are the two main types of Bunyavirus?
Arborvirus and Hantavirus
Transmitted through rodents, Deer mouse urine and pellets
-Can cause death
Hantavirus
Causes pulmonary edema via capillary leak and prerenal azotemia
Hantavirus
Another major clinical manifestation of hantavirus is
Hemorrhagic fever
Rift valley fever and California encephalitis are two forms of bunyavirus that are from the
Ades mosquito
A major neurological symptom of Rift Valley Fever or California encephalitis is
Seizures
What is the viral classification of the arena virus?
Enveloped SS NEG Sense RNA virus
Has the capacity to encode both RNA negatively and RNA positively
Arena virus
What is the caspid shape of the arena virus?
Helical caspid
What is the segmentation classification of the arena virus?
Segmented virus, only 2 can reassort
Shows a characteristic granular sandy outer caspid on EM
Arena Virus
How is the arena virus transmitted in humans?
Rodent transmission
A form of the arena virus characterized by febrile aseptic meningitides
Lymphocytic Choriomeningitis Virus (LCV)
Inactivated by heating, low pH, irradiation and detergents, just really know it’s capable of being inactivated
Arena virus
What is the viral classification of the Reovirus?
Naked, double stranded RNA virus
How many segments are there to the Reovirus?
11 segments
What is the major form of Reovirus?
Rotavirus
Rotavirus causes toxic mediated
Secretory diarrhea
The secretory diarrhea in rotavirus is caused by
NSP4
The secretory diarrhea seen in rotavirus is due to the increased permeability to
Chloride ions
The classic outbreak of rotavirus is in the
Winter
The population most at risk for Rotavirus is
Children
The #1 cause of severe diarrhea in young children
Rotavirus
