#15,538
Two days ago Danish authorities reported that they'd discovered a `new strain' of COVID-19 in minks and humans (see Denmark Orders Culling Of All Mink Following Discovery Of Mutated Coronavirus) which they feared might allow it to evade current vaccines.
Reports of `mutations' are a dime a dozen with viruses (see The `M' Word), and most of the time, they are overblown by the press and end up having little or no impact on the function of a virus.
When viruses jump species, however, they can sometimes develop more focused `host adaptations'. We see this demonstrated in the classic serial passage experiment (see below), which can often - over as few as a dozen serial passages - produce a `better' host adapted virus.
Over time, the passaged virus tends to adapt to the new host (assuming there are no species barriers to prevent it), sometimes increasing replication, virulence, and/or transmissibility.
This is why so much emphasis was placed early in the COVID-19 pandemic on finding out what species - other than humans - might be suitable hosts for the virus (see Susceptibility of Ferrets, Cats, Dogs & Other Domestic Animals to SARS-CoV-2).
While dogs and cats were found to be only mildly susceptible - and SARS-CoV-2 replicated poorly in dogs, pigs, chickens, and ducks - ferrets, and farmed mink have proven excellent intermediate hosts for the virus.
And when you have the virus spreading through literally millions of highly susceptible farmed mink, you essentially have an uncontrolled serial passage experiment on steroids.
While the extent of the threat this new `mutated' coronavirus poses remains far from clear - today Danish authorities ordered a month-long lockdown and testing of more than a quarter of a million residents in a bid to control the spread of this recently discovered strain.
The (translated) details of this lockdown, and the steps the Danish government has ordered to try to contain this new variant, come from the official https://coronasmitte.dk/ website.
I'll have a brief postscript when you return.
In order to reduce the development of infection in Hjørring, Frederikshavn, Brønderslev, Jammer Bay, Vesthimmerland, Thisted and Læsø municipalities, where a number of citizens are infected with mink virus variants, a number of local restrictions and measures are implemented in the municipalities in question.
Measures to reduce infection development in North Jutland
To reduce the development of infection in Hjørring, Frederikshavn, Brønderslev, Jammerbugt, Vesthimmerland, Thisted and Læsø municipalities, where a number of citizens are infected with mink virus variants, a number of local restrictions and measures are implemented in the municipalities in question.
It has been decided that all mink herds in Denmark must be slaughtered. The restrictions and measures must be seen in this context. The first priority is to reduce the mink herds in the affected municipalities.
In this connection, the action group, including the health authorities, recommends that the following measures be implemented.
The measures are provisionally valid until and including 3 December 2020. The necessary rule changes will take effect on 9 November 2020.
At the national level, a comprehensive sequencing of positive tests from across the country and targeted infection detection are initiated in order to identify and contain infection with the mutated virus in the rest of the country. The capacity for sequencing is significantly upgraded in order to be able to sequence all positive tests in Denmark.
RULES APPLY PROVISIONALLY UNTIL AND INCLUDING 3 DECEMBER 2020
Geographical mobility
- All residents of the affected municipalities are strongly encouraged to cross municipal boundaries only if essential and urgent considerations so require, including the performance of critical functions.
- Everyone residing outside the affected municipalities is strongly encouraged not to enter the affected municipalities unless significant and urgent considerations so require, including the performance of critical functions.
- Employers in the affected municipalities are strongly encouraged not to accept employees, customers, traders, etc. residing in another municipality. This applies not least to travelers from abroad.
- Migrant workers should, as a rule, remain in the municipalities concerned during the period in question and are encouraged, if necessary, to return to their home country to be tested in advance.
- Persons residing outside Denmark are strongly encouraged not to enter the affected municipalities.
- Entry into Denmark to take up residence in or work in the affected areas during the mentioned period will from 9 November 2020 as a starting point not be a recognizable purpose. Danish citizens and persons residing in Denmark may, however, travel into Denmark regardless of purpose.
Public transport, etc.
- Public passenger transport is closed with e.g. bus, train and ferry in and out of the affected municipalities and across the municipalities, except for driving with school buses and the like.
- It will have to be ensured that people who perform critical functions in, for example, the health and care sector can continue to show up for work. It is sought to agree with Nordjyllands Trafikselskab that they make flextur available for this group. This should be considered an emergency scheme and anyone who has private means of transport, including a car, or has other options is encouraged to use them.
- It is also encouraged that transport schemes with flexi-traffic (in accordance with the Health Act and the Service Act as well as individual disabled driving) are, as far as possible, only used in health-critical situations.
Massive test effort
- Everyone residing in the affected municipalities is encouraged to be tested during the period in which the measures apply.
- There are local announcements about when and where tests should be carried out, which you should wait before booking a test yourself - unless tests are booked for other specific reasons such as mild symptoms and test time for close contacts.
- The test capacity (grafting and analysis capacity) in the North Jutland Region is increased, among other things. by redistribution of capacity from other parts of the country.
- If persons from the affected municipalities have compelling reasons to travel out of the country, they are strongly encouraged to be tested prior to departure. Employers are encouraged to support such testing of employees.
- People related to mink farming are encouraged to get tested frequently (every 3-4 days).
- Sequencing of all positive samples is initiated.
(Continue . . . )
We'll have a much better handle on its potential impact once scientists around the world can get a good look at the sequences, and we get some data on its prevalence in the local population.
Regardless, the lesson from this week is abundantly clear. Viral evolution can sometimes produce curve balls, and we shouldn't be surprised if this pandemic delivers more of them in the months ahead.
