The mystery individual infected with the Brazil variant of coronavirus has been found in south London.
On Tuesday, health secretary Matt Hancock told MPs the hunt had been narrowed down to just 379 households. Six cases of the variant of concern have been found in the UK – three in Scotland and three in England.
On Monday, surge testing began in South Gloucestershire after two cases of the variant were detected in one local household which had a history of travel to Brazil.
The discovery of the errant case – which was blamed on no contact details being left – was confirmed at the Downing Street press conference on Friday, where Hancock revealed the person carrying the variant had been found in Croydon.
The individual had recently travelled back to the UK from Brazil, and had been quarantining at home in London, but testing would still be expanded in the area. Public health officials said all of the contacts of the unnamed person had been traced.
Hancock told the news briefing: “Using the latest technology and with the dogged determination of our Testing and Tracing scheme, we have successfully identified the person in question.
“The best evidence is that this person stayed at home and there is no evidence of onward transmission but as a precaution we are putting more testing in in Croydon where they live to minimise the possibility of spread.”
The variant – known as P1 – was detected in Brazil and in travellers from Brazil to Japan, and was associated with a surge of cases in Manaus late last year.
Dr Susan Hopkins, strategic response director at Public Health England, said a team of 40 were able to locate the mystery individual who had tested positive for the Manaus variant.
She told the press conference the individual had “attempted to register his test online but had failed to do so effectively”.
“Specialist teams from NHS Test and Trace and Public Health England (PHE) immediately launched an investigation to identify the individual concerned,” Dr Hopkins continued.
“An incident team of 40 people from across the system made up of laboratories, logistics, data analytic experts were mobilised to trace the individual.”
The discovery, via reading the test barcode, that the sample had arrived at the Cambridge Lighthouse through the DHL service for home delivery helped narrow it down to two regions made up of 10,000 possible households.
This was then narrowed further to 379 households with “enhanced contact tracing” then kicking-in, with call handlers contacting those who could have received a test in that time interval, scaling it down to 27 individuals before the person then came forward.
As government officials were scrambling to track down the mystery case of the worrying Brazil strain, other Covid variants were being monitored carefully.
PHE said on Thursday that 16 cases of another new variant, thought to have originated in the UK, have been identified. It has been designated a “variant under investigation” (VUI).
Variants of Covid-19 can be identified as VUIs or “variants of concern” (VOCs).
New variants emerge regularly and experts are conducting frequent analysis to see which are of concern, and which are not.
The latest identified variant, also known as B.1.1.318, contains the E484K mutation, which is found in two other VUIs present in the UK, but it does not feature the N501Y mutation that is present in all VOCs, PHE said.
The findings mean there are now four VUIs and four VOCs being tracked by scientists in the UK.
Other VUIs include one from Brazil, known as P2, which has had 43 probable or confirmed cases identified in the UK, but is not causing scientists serious concern.
This article originally appeared on HuffPost UK and has been updated.