FINAL - Covid-19 Virus notes Flashcards
What kind of virus is covid?
A medium-sized enveloped positive stranded RNA virus.
The host-derived membrane of the virus is studded with glycoprotein spikes that surround the viral genome, which is encased in a nucleocapsid.
HOw does the infection of the host occur with coronavirus?
The Spike proteins mediate receptor binding and fusion with the host cell membrane. Infection of host cells occurs via binding of the viral spike protein to angiotensin-converting enzyme 2 (ACE2) receptors.
Describe the course of the infection with coronavirus?
When viral spike proteins enable host cell entry via binding to angiotensin-converting enzyme 2 (ACE2) receptors and viral replication begins, infection of nasal and bronchial epithelial cells and pneumocytes generally occur early in infection . Later in infection acceleration of viral replication and compromise of epithelial-endothelial barrier integrity results in a dysregulated inflammatory response and a hypercoagulable state. Dysregulation of the renin-angiotensin-aldosterone system may also contribute to infection-related tissue damage.
Describe the most commone variant of covid right now?
OMICRON
How many confirmed cases of covid have their been internationally? How many deaths?
776 million with over 7 million deaths
These numbers do not accurately reflect the actual total of COVID-19 cases worldwide. Only a fraction of acute infections are diagnosed and reported.
How is covid-19 transmitted?
The COVID-19 virus is transmitted primarily via person-to-person contact by both symptomatic and asymptomatic individuals. This occurs through close contact (within 6 feet or 2 metres) via respiratory droplets. Potential routes of transmission include respiratory secretions from coughing, sneezing, and talking if it is inhaled or makes direct contact with mucous membranes.
Transmission risk is greatest if contact is prolonged for 15 minutes or more.
What increases the risk of transmission of covid-19?
Transmission risk is greatest if contact is prolonged for 15 minutes or more. The risk of transmission after contact with an individual with COVID-19 increases with the closeness and duration of contact. It appears highest with prolonged contact in indoor settings. Transmissibility, incubation period and infectivity varies depending on the virus variants and the individual’s immunity. The viral attack rate among household contacts for Omicron variants is estimated at 43%.
Describe other transmission routes aside from person to person?
Further routes of transmission such as aerosols and via contact with fomites are possible; however, these are not the primary routes of transmission. Although not a primary route of transmission, SARS-CoV-2 can also be transmitted longer distances through the airborne route via inhalation of particles that remain in the air over time and distance. This risk is enhanced in small, poorly ventilated spaces.
How is Covid infection spread via asymptomatic individuals?
As previously mentioned, COVID infection via asymptomatic individuals is possible. Viral shedding in the upper respiratory tract begins about 2-3 days prior to symptom onset. Asymptomatic carriers can transmit virus 1-3 days before developing symptoms. Peak viral load occurs around the time of symptom onset. The infectivity period can be affected by disease severity, pre-existing immunity through vaccination, or prior infection.
Is covid-19 seasonal yet?
The seasonality of COVID infections has not been established but COVID-19 activity is expected to be elevated in fall and winter months (associated with more indoor congregation for activities in colder months). Immunization programs have been targeted for fall, with release of updated vaccines each year, to coincide with influenza vaccination campaigns for ease of program administration and in hopes of optimizing vaccine uptake, which has waned over recent years.
What is the clinical presentation of Covid-19
Infection with SARS-CoV-2 often presents quite similarly to other viral influenza-like illnesses. It is also possible that those who are infected may present with little to no symptoms at all. For this reason, testing is encouraged to determine whether or not symptoms are due to COVID-19 infection and to guide further management. Criteria for testing and isolation vary from jurisdiction to jurisdiction.
What is the gold standard testing for Covid-19?
Molecular testing
Is a reactive result on a RAT considered diagnostic of Covid?
Yes!
A reactive result on a rapid antigen test should be considered a positive diagnosis; a negative result may mean that the person has tested too soon or insufficient sample, and retesting daily for 3-5 consecutive days when symptoms are present can be helpful. Swabbing the cheeks and back of the throat before the nasopharynx is recommended for rapid self-testing.
When do patients become symptomatic after exposure to covid?
Patients may become symptomatic anywhere from 1-14 days after exposure to the virus, but typically symptoms appear between 3-7 days
What symptoms can Covid-19 show?
-Sore throat
- Runny nose
- Sneezing
- New or worsening cough
- shortness of breath or difficulty breathing
- Temperature equal to or more than 38degree C
- Feeling feverish
- Chills
- Fatigue or weakenss
- Muscle or body aches
- New loss of smell or taste
- Headache
- Abdominal pain, diarrhea, nausea, and vomiting
- Feeling very unwell