Respiratory Viruses And Covid 19 Flashcards
Rhinitis
Colds
Swelling redness runny nose not major issues
Rhinitis are caused by
Corona viruses and rhinoviruses
Hantavirus
Sporadic outbreaks in the US
Spread of mice
Outbreaks all related to increases in rodent populations
Fatality rate of 33%
Measles
Caused by paramyxovoridae
sSRNA enveloped virus
Why is one of the most contagious disease ever discovered
Measles
Can be detected in the air and on fomites in an area where an infected person has coughed up to two hours later
Symptoms of measles
Fever watery eyes dry cough etc
White spots in mouth called kopliks spots
Begins on face then spreads
Fever spikes
Complications of measles
Ear infections
Diabetes
Pneumonia
Enchaphlitis (swelling of the brain)
Subacute sclerosis from oananchalitis (Dawson’s disease) chronic progressive brain inflammation
Measles numbers after vaccination
From 200,000 cases 1963 to about 200 in 2002
Current day: 23 separate outbreaks. Why?
Influenza
Second most common virus after rhinovirus
Most major are from GROUP A
cases increasing drastically in morbidity
Influenza is what kind of cell
Single stranded RNA virus
Influenza goes from RNA to what
sSRNA to mRNA
(No DNA) step unlike HIV
How many genes does influenza have
10
How many RNA strands with regions that code for different protiens on each strand for influenza
8
What does it mean that influenza has no proofreading enzymes
Mistakes approximately made once every 10,000 nucleotide so the degree of mutation is very high
2 major antigens in influence surface
Hemagglutinin
Neuraminidase
Hemaggkutinin
Binds to host cell receptors for docking (influenza)
Neuraminidase
Digests away mucus in surface respiratory cells (influenza)
We name strains of influenza protiens based on what
Different forms of hemagglutinin and neuraminidase
Antigenic drift
Mutations lead to changes in surface antigens because of natural mutation
Why would u want a high rate of mutation for an antibody binding site
If you can change the structure of site for antibody binding then the body needs to learn all over again how to fight a new structure
Antigenic shift
Viruses are sloppy, you get mix ups of RNA inside viruses so it’s swapping whole RNA strands (each with 1 or more genes) with other viruses
So you can get human influenza with a duck antigen
Antigenic shift consequences
Any prior immunity is lost
Vaccines may be in effective
Major flu pandemics start this way (swine flu, bird flu)
Influenza vaccine information
Vaccine is determined each summer based on observed strains from the year before the strains are prevelanr in other countries
How does influenza virus bind and infect
Virus binds to ciliates cells lining the respiratory system
Dry cold air disrepute mucus and cell structure underneath, making the respiratory mucosa more susceptibility to viral infection
Two previous recent outbreaks due to coronavirus
SARS (2002-2003) ASIA
MERS (2012-2019) Saudi Arabia
Super her fatality rate even if infections numbers are not super high
What kind of cell is coronavirus
Large enveloped RNA virus rhat infect birds and a wide range of mammals including humans
Large so it engulfs the cell
Enveloped so it doesnt survive well outside of body (dries out)
RNA so it has a higher probability to infect new host species because of it exceptionally shorter generation time and faster revolutionary rate
What is SARS
severe acute respiratory syndrome
Caused by a coronavirus
Enveloped
SARS pandemic season
Flu season like winter (when people are more vulnerable)
First SARS patient
45 year old man in China
International outbreak of SARS
Medical doctor brought it to hotel of dozens of people
By the end of that month 156 patient had SARS
What does SARS do in the body
In addition to flu like symptoms, it causes muscle pain, labored breathing,
Where does SARS 1 come from
Palm civets
Primary method of transmission for SARS 1
Respiratory droplets
Some limited evidence of fomite transfer
Small number from sewage transport
Method of SARS
virus enters the body through the respiratory tract
Infects the epithelial cells of the airway and lungs by binding to the ACE 2 receptor and entering the cytoplasm of the cell
Pneumonia results leading to inflammation alveolar collapse recruitment of macrophages and formation of syncytia
As it proliferate the virus also affects immune cells and can be carried immune organs including the spleen lymph nodes and other lymphoid tissue
MERS
Middle East respiratory syndrome
Single stranded RNA viruses
Enveloped
Clinical features of MERS
rapidly progress and leads more to organ failure
Mkre white color in lung images
More collapsed alveoli
Transmission of MERS
camels to humans direct or indirect contact
Possibly came from Bats
Mechanism of MERS
Used DPP4 which is common amongst a wide range of organisms
Pneumonia results leading to inflammation, alveolar collapse, recruitment of macrophages and neutrophils
How to be eligible for SARS and MERS testing
Exposure to infection as well as symptoms
Tests for SARS and MERS
Antibody tests
Nucleic acid tests
Lymphocyte count can help predict patient outcomes
Steps of outbreak containment
Public alert issued on personal protection. Addition of SARS as notable disease Suspension of schools Limitation on travel Isolation of residents Home quarantining Body temp checks
How does SARS covid 2 infect a cell
- Virus enters through nasal passages
- The spike protein attaches to cell receptors —angiotensin converting enzyme 2 (ACE2)
- Viral membrane fuses with the cell membrane
- RNA genome is released into the cell
- Cell replicates virus using its RNA genome
What are the differences between DNA and RNA viruses
Do you know viruses are mostly double stranded while RNA bars are single-stranded. RNA mutation rate is higher than the DNA mutation rate. DNA replication takes place in the nucleus well RNA replication takes place in the cytoplasm. DNA viruses are stable while our new viruses are unstable
