Lecture 15 Flaschards Flashcards
The SARS (2002-2003) epidemic was effectively ended by ___ ___ only!
case tracking
Describe the first recorded infection of SARS
Chinese public servant in Foshan was the index case (patient 0).
Where was the initial outbreak of the SARS epidemic?
Food industry workers in Guangdong province (farmers, market vendors, chefs)»_space; healthcare workers.
What was the first superspreader event in the SARS epidemic?
Zhou Zuofen a fishmonger: Led to infection of 30 nurses and doctors at Sun Yet-Sen Memorial Hospital, Guangzhou. Virus spread to nearby hospitals.
What was the first international super spreading event?
Physical at SYSMH who ate at a restaurant in Guangzhou then stayed in Hong Kong’s Metropole Hotel (Room 911)
Describe the case tracking of the first international sueprspreading event of SARS?
The physical guest spread SARS to 23 guests in hotel Metropole and other parts of Hong Kong.
Another Metropole guest went back to Canada and spread SARS to family in Toronto and a local hospital there.
Another Metropole guest spread it to Singapore.
Another spread it to Vietnam
Another spread it to Hong Kong and infected 99 people.
Where was a substantial amount of virus found at the Metropole hotel?
The hotel registration desk accounted for 4000 of 8000 total global case.
What were the potential reservoirs of the SARS (2002-2003) epidemic?
More than 1/3 of the early cases before Feb. 1 2003 were in food handlers.
Shenzhen live animal market; 3 samplings; 9 species; 25 animals.
Masked Palm Civets 6/6 virus isolation or PCR pos (nasal/fecal)
Raccoon dog (virus isolation)
Chinese ferret badger/
What was the actual reservoirs of the SARS (2002-2003) epidemic?
Local reservoir of Horshoe bats
What was the vector of the SARS (2002-2003) epidemic?
Virus survives in
stool and urine for at least 2 days
diaorrehal stool for up to 4 days
dried at room temp for at least 2 days
Acetone fixed slides
At -4 degrees C and -80 degrees C at least 21 days with minimal reduction.
On paper or plastered wall > 36 hours
On plastic surface and stainless steel > 72 hours
When does virus (SARS) typically not survive?
Commonly used disinfectants
Temp 56 degrees C for 30 min in blood serum.
Fixed in infected cells after -20 degrees C acetone fixation (freeze/ thaw).
What are super spreading hubs for potent virus spread within a population?
A hospital may be a really potent hub for deep local transmission of a virus that still lurks under the radar. Social crossroads: Broad status of social contacts (doctors, nurses, patients, visitors, deliveries, contractors, diagnostic services).
Hospitals are ___ rich
fomite
Where did one measles outbreak occur?
Disneyland in 12/2014-2/2015
What does mitigation mean in the context of outbreaks of viruses?
Non-pharmaceutical interventions may manage outbreak slow the spread but not completely stop it.
Aim is to flatten the curve
Provide time for medical countermeasures.
What are some examples of various types of mitigation strategies to combat
Self:
-hand hygiene
-wearing PPE/masks
- self-quarantine
Community:
- Physical distancing
Closing schools/cancelling mass gatherings
-Surface cleaning (families) environmental measures
- CCC (Japan) avoid closed areas crowds close contact)
Drastic:
-Quarantine entire city
- Travel ban
Middle Path: South Korea
Mass screenings and localized quarantine. Alerts on movements of infected individuals contact tracing
Singapore: Financial support on those who self quarantine/large fines on those who failed to.
What happens if mitigation strategies are inadequate in strictness or duration?
Premature relaxation of distancing rules can lead to resurgence after initial surge. Transmission may also rebound quickly (exponential system).
Why are suppression strategies employed?
Optimal mitigation policies may reduce peak healthcare demand by 2/3 and deaths by 1/2 but still result in hundreds of thousands of deaths and overwhelmed health systems.
What are suppression strategies?
This means to reverse epidemic growth.
Need to be marinated to the end otherwise 2nd wave.
-slaughtering animals
-lockdown (temporary)
-test, track/trace, isolate
What are some examples of cycles of culling and then regeneration in response to some outbreaks?
-Swine flu/bird flue (Asia) H5N1 bird flu/Hong Kong > all chickens in Hong Kong eliminated the virus
-Nipah (Malaysia pigs) > 1 million pigs destroyed.
-ASFV (Europe/Asia, pigs).
-FMDV (Europe, cattle, sheep, goats).
H 5N1 is continually taking shots at sustained human to human transmission. Repopulating the global outcry flock reloads the gun.
Describe medical countermeasures.
Final SARS eradication:
Rapid quarantine proved to be remarkably effective strategy for SARS 1 (b/c it did not yet show highly efficient human-human transmission) fairly gradual increase in number of cases and because there was to a substantial pre-symptomatic/asymptomatic contagious transmission period.
-For HIV, influenza, quarantine has not been an super effective strategy. Incubation times/clincally latent virus and higher transmissibility respectively is why.
- For these viruses, sensitive/rapid diagnostics or immunization strategy.
What are the main key points of lecture 15?
1) Epidemiological investigation: Investing an outbreak SARS 1
Index Case
Reservoir
2) Real time investigation SARS 1
Deducing vector (fomites)
Deducing transmission modes
Real time data including geographical and temporal changes in R0.
Super spreading
Asymptotic transmission.
