We now know that the incubation period for plague is 1-7 days, and that untreated people can be sick and spreading the bacterial infection up to around 35-37 days in some cases. So whilst the Venetians didn’t know the cause of the plague their observations and adjustments to time scales of quarantine were actually very effective in preventing the transmission of the infection from approaching boats… not so much by land though as originally “quarantena” only applied to shipping.
Apparently the principal of quarantine is even mentioned in the Bible!; I kid you not… in the Book of Leviticus 13:4 there is mention about isolating a person with a white spot for 7-14 days to ensure it doesn’t spread. Obviously this makes me think “I wonder what the disease they were worried about was”; bubonic plague, smallpox, leprosy?? I digress…
I find quarantining those with leprosy particularly tragic as infection with leprosy resulted in people being cast out from society and forced to live in isolated communities. The irony is that leprosy isn’t actually that infectious, and only really affects a minority of people with specific genetic predisposition, so people with leprosy weren’t that much of a risk to the rest of population, but “fear of disease” is a powerful motivator and often leads to unacceptable behaviour (don’t worry, I’m not going to get on my Covid-19 soap box here!)
So quarantine has been around for a long time, but should we still be quarantining people with infections for 40 days?
How long should someone be quarantined for?
Whilst the term quarantine strictly speaking means 40 days we are no longer so rigid about this. We still use the word quarantine to describe a period of “enforced” isolation but the time period is now more flexible.
Nowadays the time period in which a person might be able to spread an infectious disease is used to determine the length of quarantine, and this varies between different infections. The time also does not necessarily start at day 0 if the incubation period has a minimum time* e.g. the earliest someone exposed to chicken pox can become infectious is known to be 10 days, and they are infectious up to 21 days after exposure so the quarantine period is for between day 10 and day 21, not from day 1 of exposure.
These are some of the more important quarantine periods in current clinical practice:
- Covid-19 = 14 days
- *Chicken pox (Varicella Zoster) = between day 10 and day 21
- *Measles = between day 7 and day 18
- Influenza = 7 days (14 days if immunodeficient)
- Viral gastroenteritis = 72 hours
- Viral Haemorrhagic Fever e.g. Ebola = 21 days
What should you do during quarantine?
It is important to remember that you might be infectious during this period, even if you feel well. The critical things to do are:
- Minimise contact with other people as much as possible, especially close physical contact e.g. kissing, and stay at home or wherever you are meant to be; if you need something from the shops ask someone else to get it for you
- Pay close attention to hygiene, especially with hand washing, and don’t prepare food for anyone else in the house
- If you have diarrhoea try to have a separate toilet to others within your household and clean it regularly with disinfectant
- Be last in the shower or bath or use a separate one if able
- Don’t share things like toothbrushes, water bottles or drinking glasses unless they have been cleaned between times
- Stay active and busy…play games and don’t get bored (is it inappropriate to recommend Pandemic Legacy?!)
- Use common sense about how you might spread something…
Do we quarantine patients in hospital?
In the past I would have said we didn’t quarantine patients in hospital, but with Covid-19 this has actually changed. Hospitals are now asking patients who have an operation or procedure planned, to quarantine themselves at home for 14 days before their admission in order to prevent them bringing the SARS Cov2 virus back into the hospital. But hey, at least they are not insisting on 40 days!
In normal infection control practice we don’t tend to use the term quarantine, we use the “jargon” source isolation and protective isolation:
- Source isolation protects staff and other patients from acquiring infections
- Protective isolation prevents vulnerable patients from catching infections
Patients with transmissible infectious diseases should be nursed in single occupancy rooms (side rooms) with en-suite toilet and separate hand hygiene facilities. The door should remain closed at all times. Some patients need to be nursed in negative pressured rooms, which draw air into the room thereby preventing airborne microorganisms exiting to other clinical areas. Source isolation is the closest we come to quarantine in our normal day-to-day infection control practice.
Patients who are immunodeficient should be nursed in single occupancy rooms (side rooms) with en-suite toilet and separate hand hygiene facilities. The door should remain closed at all times. Some patients will need to be nursed in positive pressured rooms, which push air out of the room thereby preventing airborne microorganisms entering the room and exposing the patient.
Protective isolation is not quarantine, it is actually the opposite. We are not isolating someone who has been exposed or has an infection but rather anyone who is particularly at risk of acquiring an infection or getting very sick with it; they are being protected.
So here you have it. “Quarantine” is a 14th century term that has become part of everyday chatter, but like many old terms it’s meaning has been changed slightly. Now when we say quarantine we don’t mean stay on you boat for 40 days, but rather (where have you been on holiday!?) keep in source isolation for a more specific defined period of time. But the purpose is the same; do not spread infections to other people. It appears those Old Venetians knew what they were doing after all… Venice… is that on a list of “non-quarantine travel”? Apparently it is, but given the way cases are increasing it may not be by the time you read this!