Medical experts are trying to understand an aspect of the epidemiology of the coronavirus, as three of the latest confirmed cases tested positive long after the 14-day incubation period, and none of the three had any symptoms.
Three of the four patients to test positive were among 68 cruise ship passengers who were put in isolation at a facility at Balandra on March 18 after their return to TT.
They had all previously tested negative for the virus and were being readied to be sent home.
Speaking at a media conference on Sunday, Chief Medical Officer Dr Roshan Parasram described the most recent infections as "quite unusual," as the coronavirus was originally thought to have an incubation period of only 14 days.
In this case, the three most recent cases tested positive after being kept in isolation for 24 days.
He said information was forwarded to virologists at the Caribbean Public Health Agency (CARPHA) to try to explain the apparent change in the behaviour of the disease.
Parasram said one of the most recent cases was the wife of a confirmed coronavirus patient, and suggested she may have contracted the disease by being in close contact with him, but could not explain the source of the other two infections.
He was working with the county medical officer to get more details of these cases.
"In terms of those three people that tested positive, they would have had a first negative (result), just like the other 19 people before them,” he said. "They had no symptoms. But we are beginning to look at why they had a positive (result), so long after testing negative and then having no symptoms as well, so it is an unusual situation biologically.
"I had discussed it with the head of virology as well at CARPHA to some extent.
“What I can say for one of the patients who turned out to be positive had very close contact with another positive patient in Balandra who was her spouse, so there was a close link."
Parasram said also said despite the anomalous nature of the latest infections, proper hygiene and social distancing protocols were practised at the Balandra facility.
He also pointed out that the virus was new and therefore relatively unknown in its behaviour and patterns of infection.
On March 21, three days after the group was sent into isolation at the Balandra camp, it was confirmed that of the 68 passengers, 40 had tested positive for the coronavirus. They were transferred to the Couva Hospital for treatment.
The 14-day quarantine period for the remaining 28 at the Balandra camp was restarted.
By March 27, the Ministry of Health confirmed that 47 people of the original 68 at Balandra tested positive for the coronavirus.
As of Sunday afternoon, the number of confirmed coronavirus cases from the cruise stood at 52. This number includes three people who returned separately from Guadeloupe.