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Recent Outbreaks - Coggle Diagram
Recent Outbreaks
Zika Virus
Flaviviridae family
+ve ssRNA
- Vector borne, vertical transmission, sexual
Disease: Zika congenital syndrome, Zika fever, Guillain-Barre syndrome
Ebola Virus
Filoviridae family
-ve ssRNA
- Encodes 7 proteins
- 5 species recognised
- Zoonotic disease (bats-human)
- Symptoms: Fever, sore throat, vomit, diarrhoea, rash
- Fatality - 50-90%
- Spread via bodily fluid contact
Outbreaks in urban Africa (Not West), lack of infrastructure
- Transport to medical centres were slow
- Initial symptoms mistakes for malaria/ Lassa fever
- 700 health carers died in first year
Vaccines & Therapeutics
Recombinant vesicular stomatitis vaccine
- Chimpanzee adenovirus type 3
Coronavirus
Coronaviridae Family
+ve sense ssRNA
- Helical, spike proteins
Transmission: Zoonotic, aerosolised droplets, fomites
4 Common human types:
- α coronaviruses: 229E and NL63
- β coronaviruses: OC34 and HKU1
3 Recently emerged coronaviruses:
- β human coronaviruses:
SARS-CoV
MERS-CoV
SARS-CoV-2
Clinical manifestations of SARS:
- 2-10: High fever, myalgia
- 8-12: Cough, shortness of breath
- 3rd phase: Progressive hypoxia, may need intubation
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Covid-19
Mostly asymptomatic
- Risk factors: Older age, high BMI
Coronavirus Cont.
SARS-CoV Immune Evasion
- Replication inside double membrane vesicles
- By detection of infection, there is already lots of virally infected cells
- Strong immune response may cause ARDS
Acute Respiratory Distress Syndrome (ARDS)
- Early infection: Infects monocytes
- Late infection: Oedema in alveoli reduce gas exchange
Mechanisms of Pathophysiology
Many symptoms:
- Direct damage to cells
- Thromboinflammation
- Dysregulated immune response
SARS-CoV-2 Variants
From random mutations in replication
- D614G mutation increases spike density/ infectivity
Attachment
- SARS-CoV use (ACE2) as receptor
- MERS-CoV use DPP4 and sialoglycosides
- HCoV-229E uses APN
Covid-19: Diagnosis
RT PCR to detect multiple viral RNA regions
- Lateral flow tests detect viral antigens
Prevention
Face masks, social distancing, contact tracing, self-isolation
- 150 vaccines developing globally, target spike proteins
Therapeutic Targets
- Attachments and Entry
- Uncoating
- Transcription/ Translation
- Genome replication
- Assembly
- Release
Covid-19: Therapeutics
- Antivirals target virus
- Protease inhibitors
- Antibody therapies
.
Immunomodulators target immune systems
Therapeutics to treat complications in infection
- Anticoagulants to prevent blood clots
- Vit D deficiency leads to worse outcomes