B.C.’s provincial health officer says she knows the concern around hantavirus can be “unsettling” just six years after the COVID-19 pandemic began, but she wants people to know this is a “very different” virus.
Dr. Bonnie Henry provided an update on Monday on the four Canadians – two from the Yukon, one from B.C., and one who lives abroad – that arrived in B.C. on Sunday after being on the MV Hondius that was hit by hantavirus in early May.
A cluster of passengers with severe respiratory illness aboard the MV Hondius was reported to the World Health Organization on May 2. At the time, there were 147 passengers and crew on board, after 34 passengers and crew had previously disembarked.
Since then, three people have died.
Henry said nine people have tested positive, including a recent case in France from someone who just returned from the cruise ship. She added there are multiple people still in hospital, including one in South Africa, two in the Netherlands, one in Switzerland and the most recent case in France.
So, what is hantavirus?
The World Health Organization says it’s a group of viruses carried by rodents that can cause severe disease in humans, and people usually get infected through contact with rodents or their urine, droppings, or saliva.
To date, human-to-human contact has only been documented in the Andes virus in the Americas and remains uncommon, the WHO’s fact sheet says.
While B.C. doesn’t have the strain of hantavirus found on the ship, the province has seen a different strain in recent years. The last two cases in B.C. were in 2023, with Henry adding that the province sees an average of zero to two cases per year since it was first detected in the 1990s.
Transmission between people has been associated with close and prolonged contact.
Henry said hantavirus doesn’t spread the same way as coronavirus, influenza, or measles, which have also seen rising rates in recent years.
“It’s not highly transmissible and we know that too,” she explained. “And it’s not what we would consider a disease of pandemic potential. It is, however, a very serious illness.
Hantavirus vs. COVID
Henry explained that the SARS-CoV-2 virus is one that causes an infection in the upper respiratory system first, so people “shed” – or spread – quite a lot of virus through their secretions from talking, sneezing, coughing or singing.
“It spreads through the air, and we know that especially the Omicron strain of the coronavirus, it can last in the air for some time and spread quite rapidly to people, especially in closed environments with poor ventilation.
She pointed to the COVID-infected cruise ship in 2020 where the virus spread quickly, even among people who hadn’t been in contact with someone infected. She said it likely spread through the ventilation system.
Typical COVID symptoms include fever, chills and a sore throat. However, there can be less-common symptoms, such as muscle aches, severe fatigue or tiredness, runny or blocked nose, tight chest or chest pain or loss or change of sense of taste or smell.
Hantavirus is quite different, she said. It causes infections that are more deep in the lungs, and can cause kidneys to fail.
WHO says that in humans, symptoms usually begin between one and eight weeks after exposure depending on the type of virus. Those symptoms can typically include fever, headache, muscle aches and gastrointestinal symptoms, such as abdominal pain, nausea or vomiting.
Henry said there’s a global consensus that the first two hantavirus cases were contracted in Argentina – they were travelling through South America prior to the MV Hondius cruise – where there has been a “dramatic increase” in the number of people with hantavirus over the last little while.
“Then because it has such a long incubation period, they develop symptoms on board the cruise ship.”
Henry added that health officials do know quite about about hantavirus and the Andes strain so far, with whole genome sequencing being done. The strain, she said, hasn’t changed a lot, which is “something that is quite different” compared to COVID.
“That tells us that the virus isn’t mutating and causing different sources becoming more infectious or anything like that, SOo that’s also reassuring. Unlike the coronavirus, as we remember, SARS-CoV-2 it changed quite a lot very rapidly over time.”
The response to hantavirus
When the four arrived at Victoria International Airport on Sunday, Henry said they were thoroughly screened and assessed by Island Health public health officials, and everyone was wearing the appropriate personal protective equipment.
They’re all now isolating for 21 days – which began on Sunday – in the Island Health region. That could be extended to 42 days if any develop symptoms.
Henry said she doesn’t know if health officials “can be overcautious given the trauma” people went through during the COVID pandemic.
She said the response has been appropriate because it’s such a severe illness.
“That’s the thing that worries me. It’s rare.”
Beyond the confirmed cases and the possible contacts on the cruise ship, there were also two other possible exposures to the virus: a flight to Johannesburg, South Africa, from Saint Helena and another flight to Amsterdam from Johannesburg.
“And certainly, the risk to anybody outside of those who are on that cruise ship or on one of the flights is infinitesimally low, and we want to keep it that way.”
But she said the risk to those possibly exposed is “quite high, and because they come from many countries around the world, that means we really needed a strong coordinated response to make sure we weren’t exposing anybody else to the potential of being exposed to this very serious virus.”