New Zealand's latest coronavirus outbreak probably “came from Australia or Britain", according to officials tracking its source using genome sequencing.
Last week, New Zealand discovered its first locally transmitted coronavirus outbreak in more than three months and is now scrambling to contain it.
The country reported 12 locally transmitted cases in Auckland on Friday, dubbed the "Auckland August cluster", ending a run of more than 100 days without any locally transmitted infections.
Auckland, a major port city, has now been locked down for two weeks. Prime minister Jacinda Ardern has also delayed a national election due next month.
On Monday, the Ministry of Health reported nine new confirmed cases linked to previous cases in the cluster, and two cases remain under investigation but are strongly believed to be linked to the same cluster.
It remains a mystery how the virus made its way back into the country, as the international border has been closed to foreigners since March and all returning New Zealanders have been forced into mandatory 14-day quarantine.
The first case in the outbreak that authorities identified was a 50-year-old man who works at an Auckland cool store, who became ill around 31 July.
The man took a COVID-19 test after experiencing symptoms for a few days.
Officials said his family members had travelled to other cities, including Rotorua and Hamilton, and visited an aged-care centre while symptomatic.
There are now 78 active cases in New Zealand, of which 58 are linked to the Auckland family cluster, with infections reported at workplaces, schools, homes and public areas. The remaining 20 cases are people in mandatory quarantine facilities after arriving in New Zealand from abroad.
Genome testing of the latest batch of infections has confirmed it is a new strain, probably from Australia or Britain, officials said.
Scientists identified the "family" of its latest COVID-19 outbreak and revealed that its name is "B.1.1.1.", according to News.com.au.
Director general of health Dr Ashley Bloomfield said the samples had "strong links" to the genomes of coronavirus in United Kingdom and Australia.
The government earlier suggested the virus may have entered the country through freight, with a focus on the Auckland Americold facility, where several infections have now been reported.
Surface testing is underway at the facility. Australian authorities are conducting genome testing on workers from a Melbourne Americool facility, seeking any connection.
Dr Bloomfield has since said said human-to-human transmission is the most likely culprit, with surface transmission "unlikely".
Opposition parties and government critics have pointed to a breach at one of New Zealand's quarantine facilities as the likely conduit for the virus.
Local media has reported several instances of security slip-ups at the facilities. The government has said there is no evidence to support that theory, although testing is continuing. It has not detailed any alternative pathway.
In June, New Zealand confirmed two new cases of coronavirus had come from two British women, shortly after it had declared that the country was coronavirus-free.
The cases related to two women from the same family, both of whom had travelled from the UK and were given special permission to visit a dying parent after being released early from quarantine.
The women’s travel forced the government to suspend its policy of granting compassionate exemptions to its quarantine rules.
According to the Johns Hopkins University global coronavirus map, New Zealand has had 1,631 cases and 22 deaths.
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