The Ministry of Health is investigating a suspected historical case of Covid-19 detected in a crew member on board a ship docked in the Port of Tauranga.
The crew member, on board the IVS Merlion, returned a weak positive Covid-19 test with a high CT value, indicating an old infection, the Ministry said this afternoon in a press release.
The IVS Merlion arrived in New Zealand waters on October 15 after departing Indonesia on September 24.
It's believed the new suspected historical case had been infected with the virus some time ago and is no longer infectious.
According to the Ministry of Health the infection has not passed on to other crew members, all of whom have tested negative and have been on board the vessel for three weeks.
"None of the crew members have come ashore, meaning there is a very low risk of transmission into the New Zealand community.
"The case under investigation has since been isolated and administered a repeat Covid-19 test along with a blood test," the Ministry of Health states.
All crew members are being treated as close contacts until their investigation is complete, with no crew members allowed to leave the vessel until its conclusion.
The health staff and other port staff, who had minimal contact with the crew, have been informed of the suspected case.
It comes after a port worker working at the ports of Auckland and Taranaki returned a positive test on Saturday.
Dr Ashley Bloomfield today confirmed that port worker’s case is not linked to any existing cases and is not linked to the Auckland August cluster.
He said authorities believed “the most likely source” of the infection came from a ship the man worked on in Auckland on October 12 and 13.
The ship - the Sofrana Surville - came from Brisbane, went to Tauranga, then arrived in Auckland “where eight crew joined it from the Philippines on the 13th of October”. Four of the crew members have since departed.
He said the crew of the Sofrana Surville could have been the vector of transmission. He said the ship circuited around Brisbane, the Solomon Islands, Papua New Guinea, New Caledonia and New Zealand.
“The case that we reported yesterday had done some work on that ship while it was in Auckland and while wearing PPE onboard.
“We’re still getting further detail about his movements whilst onboard.”
The ship then went to Noumea, and now is on its way to Brisbane.
Bloomfield said authorities were working with the respective public health authorities in those places to see if any other crew members display symptoms.
The crew from the Philippines had all stayed at an isolation facility while in New Zealand, Bloomfield said.
Routine testing of transiting crew isn’t currently done, but authorities were now “looking at it immediately” after the incident, he said.
Another ship where the man worked on Wednesday is also under investigation to rule it out as a possibility.
“We do not believe that ship was the source of the infection as it only operates in New Zealand waters and it only has a New Zealand-based crew.”
That ship - the Ken Rei - is currently anchored off the coast of Napier. All 21 crew onboard are being treated as close contacts of the port worker.
“Crew members are receiving daily health checks via radio.”
The man worked on the Ken Rei on October 14 at the Port of Taranaki. While at New Plymouth, he stayed at the Devon Hotel, which has since been thoroughly cleaned according to its owner.
There will also be pop-up testing over the coming days at the ports and at the hotel for workers out of “an abundance of caution”, Bloomfield said.