Activity 4 The SARS Outbreak at Amoy Gardens
Most dangerous community outbreak 41% of the cases are from block E
蘋果日報 SARS cases in Amoy Gardens rise drastically in just one week Why?
Amoy Gardens A majority of victims found In Wings 7 and 8: This is the infection pattern of the virus! Source: SARS Expert Committee
淘大居民遷度假村隔離 方便入屋找尋病毒來源 Mar 31-The HongKong Department of Health imposed quarantine on Block E. The residents were later moved to an isolation camp, while the investigation team entered the buildings to find out the cause of the outbreak.
As shown in the video, all the Amoy Gardens Block E residents were moved to an isolation camp … • You are the investigators trying to find out how the SARS virus is transmitted in Block E. Action now!
Let’s recall the knowledge about transmission of diseases first … The way that viruses spread depends on the type of virus. They can spread through: • Carrier organisms – e.g. mosquitoes, fleas, rats, cockroaches • Air and water – by droplets or dust • Direct transfer of body fluids – e.g. sweat, blood saliva and semen • Surfaces on which body fluids have dried – door handles, lift buttons etc.
Let’s start the investigation! • In the video, the investigators said “Search every inch of the building for clues…” Do you have any ideas in mind of what to search for? • What samples could you collect?
air 蘋果日報 Sewage system Tips 1: List all the possibilities and collect samples. What’s next?
air virus found clean 蘋果日報 蘋果日報 Sewage system clean virus found virus found Rat Cockroach Water tank Tips 2: Now we have known which samples contain virus, then?
Sewage system 蘋果日報 Rat Cockroach Match the infection pattern? Additional Information: Some Residents suffer from diarrhoea (腹瀉) Match the infection pattern? Match the infection pattern? Tips 3: more than one sample contains virus, We have to figure out which samples match the infection pattern. But how?
Step by step Analysis Rats, Cockroaches, Sewage system Which one?
Sewage system 蘋果日報 Rat Cockroach Residents suffer diarrhoea Infection patterns match! Do not match the infection pattern Analysis result: Sewage system is the most possible cause for SARS to spread through the building!
Let’s read the summary of WHO’s report about their investigation in Amoy Gardens The sewage system of Amoy Gardens is presented in the picture
WHO’s report on Amoy Gardens “Super spreader” suffered from diarrhoea and passed the virus into the sewage system
WHO’s report on Amoy Gardens “Super spreader” suffered from diarrhoea and passed the virus into the sewage system • Virus survives longer periods in sewage • U-trap of floor drains dried up providing a pathway for the droplets containing Virus into the bathroom • Exhaust fan on, door closed • creates low air pressure in bathroom
WHO’s report on Amoy Gardens “Super spreader” suffered from diarrhoea and passed the virus into the sewage system • Virus survives longer periods in sewage • U-trap of floor drains dried up providing a pathway for the droplets containing Virus into the bathroom • Exhaust fan on, door closed • causes low pressure in bathroom • The exhaust fan sucks contaminated droplets to the light well (天井) • The viruses are carried to higher levels by the warm humid air
So….. What can you do to reduce the risk of spreading or contacting virus?
Examples • Cover your mouth or nose when you sneeze or cough. • Wash your hands with soap frequently, especially after going to the bathroom or preparing food. Dry with hot air or paper towel • Avoid contact with the body fluids of others.
After the investigation, you should be aware thatcareful analysisand logical argumentsare very important for scientific investigation.