Ontario’s Ministry of Health says it is now testing 10 people with connections to a hantavirus-stricken cruise, a shift from government remarks made earlier this week.

The province says the three “high-risk” travellers — two who were on the cruise and one who was on the same flight as a person who has since died of hantavirus — will stay in strict isolation regardless of their result.

However, a ministry spokesperson says the seven “low-risk” contacts can stop their recommended 45-day isolation if they test negative, while daily public health monitoring will continue. None of the residents currently have symptoms.

Public health officials have described “low-risk” contacts as air passengers who were on the same flight as someone with hantavirus, but weren’t in close proximity to them.

Testing without symptoms

Health officials around the world are grappling with the question of testing people without symptoms, given the long incubation period of the virus.

Last week, Dr. Joss Reimer, Canada’s chief public health officer, said they were not testing because there is no validated hantavirus test for people who don’t have symptoms.

Earlier this week, Sylvia Jones, Ontario’s health minister, echoed that guidance.

WATCH | Canada taking ‘precautionary’ approach for people on flights with hantavirus case:

Canada taking ‘precautionary’ approach to people aboard flights with hantavirus cases

Dr. Joss Reimer, chief public health officer of Canada, took questions Thursday about people who were on flights with hantavirus cases, saying that local public health teams are working to contact and monitor those individuals during the ‘at-risk’ period.

Reimer suggested testing people who aren’t symptomatic might give a false sense of security.

“If somebody is perhaps testing negative, but later could go on to develop hantavirus, I don’t want that individual to be taking their isolation requirements less seriously. So that’s the balance that we’re trying to strike in getting as much information as we can and is useful without giving people a false reassurance that might lead to unnecessary exposures,” Reimer said.

But she added that they are bringing together an expert group that will give officials “guidance on testing.”

The World Health Organization says its international hantavirus case count is 10, as the previous tally had an inconclusive test in the U.S. that’s since been confirmed as negative. Three people have died from the deadly hantavirus outbreak stemming from luxury cruise ship, MV Hondius.

The ship, with some crew still on board, is headed to the Netherlands and is expected to reach there on Monday.