# 8035
Now that Hong Kong’s first (imported) case of H7N9 has been identified, the job of contacting and testing all of her close contacts over the past two weeks becomes paramount for public health officials. Since she is in critical condition, and on an ECMO (Extracorporeal Membrane Oxygenation) machine since November 30th, getting detailed information about her contacts has proven difficult.
So far, 200 people have been contacted, and 17 close contacts have been tested (all negative for now). Those with negative results will be moved from hospital isolation and quarantined at a holiday resort while they are kept under observation. This from RTHK.
Bird flu contacts test negative for H7N9
03-12-2013
The government says 17 people who had close contact with the first Hong Kong person to come down with H7N9 bird flu have all tested negative for the virus.
This includes an Indonesian friend who travelled to Shenzhen with the women, who remains in a critical condition in hospital.
All 10 members of a family whom the sick Indonesian domestic helper worked for and six people who shared the same ward with her in Tuen Mun Hospital have also tested negative.
The Health Secretary, Ko Wing-man says these people have been moved out of hospital isolation wards and will be sent to the Lady McLehose Holiday Village for continued observation.
Although they are often used interchangeably in the press, here is how the CDC defines Quarantine and Isolation:
The CDC applies the term "quarantine" to more than just people. It also refers to any situation in which a building, conveyance, cargo, or animal might be thought to have been exposed to a dangerous contagious disease agent and is closed off or kept apart from others to prevent disease spread.
The Centers for Disease Control and Prevention (CDC) is the U.S. government agency responsible for identifying, tracking, and controlling the spread of disease. With the help of the CDC, state and local health departments have created emergency preparedness and response plans. In addition to early detection, rapid diagnosis, and treatment with antibiotics or antivirals, these plans use two main traditional strategies—quarantine and isolation—to contain the spread of illness. These are common health care practices to control the spread of a contagious disease by limiting people's exposure to it.
The difference between quarantine and isolation can be summed up like this:
- Isolation applies to persons who are known to be ill with a contagious disease.
- Quarantine applies to those who have been exposed to a contagious disease but who may or may not become ill.
Hong Kong has a good deal of experience with both isolation and quarantine procedures, as they were employed extensively more than a decade ago for the SARS epidemic. During that outbreak, 1,750 Hong Kong residents were infected, 286 died, and thousands were quarantined to prevent its spread (see SARS and Remembrance).
Since a negative quick test is no guarantee that someone who has been exposed isn’t infected (this patient tested negative twice while hospitalized before testing positive on Dec 2nd), it is prudent to try to quarantine those who have been exposed until infection can be ruled out. Since hospital isolation is overkill for asymptomatic (and likely uninfected) individuals, other arrangements that are reasonably palatable to those quarantined are desirable.
To that end, Hong Kong’s CHP has reserved cabins at the Lady McLehose Holiday Village to house those under observation. The facility is described on Gov HK website as:
Located within Sai Kung Country Parks at Pak Tam, Sai Kung, the Lady MacLehose Holiday Village has an air of tranquility and presents a charming view of the woody hillsides. Each bungalow, which can accommodate 3 to 15 persons, is self-contained with a sitting room, bedroom(s) and a toilet with shower facilities. The Camp has a capacity of 280 campers. Hirers please note that Camp facilities, such as bungalows, recreational facilities, canteen, etc., are located on different spots of a slope and connected by pavements.
This arrangement is similar to what we’ve seen elsewhere, including Singapore (see MERS: Singapore MOH Puts Quarantine Chalets On Standby). Earlier this year, in EID Journal: A Brief History Of Quarantine, I wrote about the use of quarantine and isolation with the 2003 SARS outbreak:
During the 2003 SARS epidemic, Isolation was used in the United States for patients who were ill, but since transmission of the virus was very limited here, quarantine was not recommended for those exposed (cite).
In other countries, where transmission risks were greater, quarantines were used – quite successfully – in order to contain the virus.
- Singapore was one of the first countries to mandate quarantines when more than 800 family members of SARS patients were ordered to stay in their homes.
- Hong Kong sealed part of the Amoy Gardens Apartment complex after scores of cases erupted there, and later moved all remaining residents to two holiday camps where they were quarantined.
- And Toronto, Canada closed schools and quarantined thousands in their bid to contain the virus (see The SARS Experience In Ontario, Canada).
While we don’t know how many mild or asymptomatic cases of H7N9 may have occurred, so far the number of severe cases detected by Chinese public health authorities suggests the virus hasn’t yet gained the ability to spread easily and efficiently among humans.
We have seen evidence of a few small clusters, and research over the summer suggests that the virus may not have that far to evolve to pose a pandemic threat (see Nature: Receptor Binding Of H7N9).
So public health interventions – such as quarantining those with likely exposure until infection can be ruled out – is a prudent and necessary step.
