Respiratory VIruses Flashcards
what kind of viruses does Rhinovirus replicate like
Poliovirus (Picornavirus)
Types of Influenza virus
A, B, and C
what type of influenza Virus is the most common and associated with the greatest concern
Type A influenza
comparison of Inflenza viruses frequency of isolation
A then B then C
Comparison of Influenza viruses severity of disease
A then B then C
What Influenza viruses have an Animal REservoir
A
how many Genome RNA segments are in each Influenza Virus
A:8
B: 8
C: 7
What type of Virus is Influenza
Orthomyxoviridae
Genome of Influenza
8 segments (-)ssRNA
Virion of Influenza
Enveloped
Proteins of Influenza
HA - Hemagglutinin, cell Attachment NA - Neuraminidase, viral budding and release M1 - matrix M2 - Ion Channel PB1, PB2, PA - TRanscription complex
what proteins on Influenza lead to an immune response
HA and NA
How is INfluenza identified
by surface antigens HA and NA
types of HA and NA
16 HA
9 NA
what is the major determinant if Influenza infects birds or human
HA specifically the Sialic Acid Linkage
alpha 2, 3: Avian
Alpha 2, 6: Human
What part of Influenza is the major determinant for human to human transmission
HA
where Does Influenza Virus type A tend to live
water birds in the GI tract as an illness
Roll of HA protein in INfluenza Virus
Attachment brings cell and Virus membranes into proximity
what triggers a confirmational change in HA protein
after cell attachment by pH change in endosome
confirmationchange in HA protein leads to
membrane fusion
the enternce pattern of Influenza serves as a model for
all enveloped viruses enternce patterns
where does Transcription and replication take place for influenza
In the Nucleus
how does the genome of Influenza leave the nucleus
The protected genome (RNP core) escapes nucleus and buds from cell surface
what Influenza protein is critical to budding
NA
How does Influenza travel
by Aerosol, both large and small drops
what size of particle is most infectious
less then 10 microns
Incubation time for Influenza
1-4 days
how long is Influenza Contagious
Day before symptom onset to 5 days later
Children are infectious for longer
what is the EID50 for Influenza
as low as .3 to 6 (People are better for relicating than eggs)
Response to Influenza virus
Interferon response then nasal wash neutralizing antibody serum antineurimidase antibody Serum Neuratralizing antibody takes about 2 weeks for these to become a big thing
what kind of disease is Influenza timing wise
Seasonal (interpandemic) flu
Syptoms of Influenza
Fever, Malaise, Nonproductive cough, sore throat for 3-7 days after symtpoms develop
what type of Influenza strains are around rn
H3N2, H1N1
Contagiousness of Influenza Virus
Reproductive number between 1 and 2
Complications associated wth Influenza virus
Viral Pneumonia
Bacterial pneumonia
Reye syndrom (Type B + aspirin)
Otitis Media
What kind of Vaccine is the Influenza Vaccine
Atenuated Live vaccine
why do we need new vaccine for Influenza each year
Virus Mutations cause an antigenic shift
lead time for Influenza Vaccine
Long lead time( due to reproduction needs and eggs take time to make)
what is contained in the Influenza vaccine
H3N2, H1N1, and Type B strain
how is the Type A strain of Influenza vaccine generated
through reassortment via coinfection with PR8 strain
Treating Influenza Virus
Antiviral treatment
Zanamivir or oseltamivir (tamiflue)
Supportive care
what antiviral treatments are there for Influenza Virus
Amantidine, rimantidine
how antiviral treatments fight Influenza virus
Blocks entry
Inhibits M2 activity
problem with antiviral treatment
Development of resistance common
how does Zanamivir or oseltamivir (tamiflu) work
Blocks release of budding virions - easier to be targetted by antibodies
resistance of influenze to Tamiflu
resistance is not common
The 4 Influenza Pandemics
1918 Spanish Flu
1957 Asian Flu
1968 Hong Kong Flu
2009-2010 N1N1
Strain of Influenza for the Spanish FLu
H1N1 strain
deaths from the Spanish flu
20-40 million
where was the Spanish flu Virulent
In healthy adults
what did the Spanish flu cause in lethal cases
Cytokine storm
strain for the Asian flu
H2N2
who did the Asian Flu kill
6 Million deaths, mostly elder and young children
strain for the Hong Kong Flu
H3N2
Deaths of the Hong Kong Flu
2 million
deaths from the 2009-2010 H1N1 Flu
8k-18k deaths
where does inlfuenza pandemics arise from
arise from avian strains
how did people get the Spanish flu
Avian H1N1 flu somehow jumped from birds to people
how did people begin to Asian Influenza
H1N1 in humans went through a reassortment with Avian H2N2 so that it could then infect humans. HANA genes and PB1 genes came from the avian part and the rest from the human part
how did people then get the Hong Kong Influenza
Human H2N2 from the asian influenza went through reassortment with H3 avian virus to make H3N2
what generally is the lead in for a Influenza pandemic
jump from bird strain to human or a reassortment of the human strain with a bird strain
types of Avian Influenza
highly Pathogenic
Low Pathogenic
strains for highly Pathogenic Avian Influenza
H5 or H7 strains
who did the highly Pathogenic Avian Influenza kill
Lethal in greater the 75% of 6-8 week old susceptible chicks
how does highly Pathogenic Avian Influenza replicate throughout the entire body
HPAI strains have multi-basic residues at HA cleavage site allowing for replication
symptoms of highly Pathogenic Avian Influenza
Skin lesions, necrotic and swollen combs, systemic infection
Symptoms of Low PAthogenic Avian Influenza
Asymptomatic to slight respiratory infection
no lesions
what can H5 and H7 strains of Avian Influenza mutate into
HPAI strains
Dutch research into the avian influenza cuased great controversy becasue
Using the H5N1 strain, high mortality rate in people, beggging the question if H5N1 could adapt to Humans
how did the Dutch researchers see if H5N1 could kill
PAssaged virus in ferrets to model human
what hapened once H5N1 virus began replicating in ferrets
after 10 generations, virus was capable of airborn transmission between animals
how did H5N1 begin to become airborne
5 mutation in 2 genes in HA that alter sialic aid binding
how is Adenovirus characterized
by serotype
serotype of Adenovirus is assocated with
with diferent diseases
what types of Adenovirus are most frequently studied
2 and 5
Adenovirus is what type of virus
Adenoviridae
Genome of Adenovirus
dsDNA
Virion of Adenovirus
Non-enveloped
Proteins in adenovirus
Fiber : cell attachment
Penton base: cell entry
Hexon: Capsid
entry of Ednovirus
Entry via coxackie-adenovirus receptor(CAR)
how does the Capsid for adenovirus disassemble
pH triggers
where does Adenovirus go once the capsid has disassembled
moves to the nucleus via microtubules
3 phases of Gene expression for Adenovirus
Immediate - earlly
Early
Late
what part of the genome is involved in the immediate early part of adenovirus
E1A portion of the Genome
what regulated the E1A prtion of Adenovirus genome
2 transcriptional regulators from the cell and virus
importance of the Immediate-early stage of adenovirus
necessary to reach the early stage
Genes involved in the gene expression stage for Adenovirus
5: E1B, E2, E3, E4, and L1
what occures in the Early gene expression phase of Adenovirus
DNA replication and post transcriptional events
what occures in the late gene expression phase of Adenovirus
Take over of cellular mRNA synthesis
where is Genome replication began for Adneovirus
on either end becuase of identical end sequences
what direction does replication occur for Adenovirus
in the 5’ to 3’ direction, and one strand is displaced
what happens to the displaced strand with Adenovirus
circularizes to allow template copy to be made
what protein is used to PRime genome replication in adenovirus
protein pTP (this unusual priming strategy
What does Adenovirus need to complete replication
a replicating cell
When does DNA replication occure
during the S phase
problem with needing a replicating cell for Adenovirus to continue replicating
not all cells are actively replicating
How does Adenovirus force a cell to express genes from S phase
E1A inactivated pRb, which leads to S phase gene expresion
E1B inactivates p53 leading to S phase and preventing apoptosis
the method in which Adenovirus brings about S phase is similar to what and may lead to what
Oncogenic processes and may lead to oncogenic tumors
what does the E3 gene of Adenovirus produce
Proteins important to host immune evasion
how does the E3 gene act to evade host immune system
Blocks MHC class I expression reducing CTL cell killing
Blocks TNF induced apoptosis
Blocks IFN-alpha and IFN-beta action keeping protein translation active
What disease does Adenovirus cause
Acute respiratory disease
Respiratory infection is how common from virus
5-10% of all viral infections
when do most adenovirus respiratory infection occur
before the age of 14
symptoms of adenovirus
same as common cold (Nasal congestion, inflammation, cough)
Adenovirus serotypes associated with Adenovirus REspiratory disease with symptoms the same as the common cold
1, 2, 5, and 6
Symptoms of Acute respiratory disease from Adenovirus
Severe pneumonia
risk factor for acute respiratory disease
Seen in military recruits due to crowded conditions and fatigue
serotypes for acute respiratory disease
4 and 7
Prevention of Acute REspiratory disease from adenovirus
vaccine for military personnel 17-50 yeras old
What does Adenovirus cause
Respiratory infections
Acute respiratory disease
Use of Adenovirus in research
often used as a vector in gene therapy research
Rhinovirus is the frequent cause of what
mild upper respiratory infection
diversity of Rhinovirus
large antigenic diversity (100 serotypes)
why is there no vaccine for Rhinovirus
too many serotypes
Rhinovirus reservoir
Humans the only reservoir
How does Rhinovirus attach
intercellular adhesion molecule 1 (ICAM-1) or the very low density lipoprotein (VLDL) receptor
Incubation period of RHinovirus
1-4 days
duration of virus shedding of Rhinovirus
3 weeks after illness
Illness legnth with Rhinovirus
2-3 days
Symptoms ofood Rhinovirus
Red nose (hyperemic), blood vessel dilation Nasal discharge that becomes mucopurulent (neutrophils) Epithelial damage likely due to the immune response
Prevention of Rhinovirus
No vaccine: too many serotypes
No antivirals: resistant mutants
What type of Virus is Ebola
Filovirus
Gnome ofebola
RNA
Virion of ebola
Enveloped
Nucleocapsid of Ebola
Helical nucleocapside, with polymorphic particles
Transmission of Ebola
Primarily body fluid
also maybe inhalation
symptoms of Ebola
Viral hemorrhagic fever
Fever, headache, vomiting, diarrhea, bleeding
Incubation period of ebola
2-21 days
Treatment of ebola
Supportive care
Experimental treatments
Vaccine - ChAd3-ZEBOV, VSV-EBOV, others…
