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As the world races to understand more about the rapidly emerging outbreaks of monkeypox, the speed with which cases are detected points to a major shift in the virus’s behavior and ability to spread from person to person unnoticed.
Five cases of monkeypox It was confirmed in Quebec and Canada’s top public health official said the provinces on Friday were continuing to investigate ‘A few dozen’ possible cases Across Canada – likely to be confirmed in the coming days and weeks.
World Health Organization (WHO) He said Friday that there are currently about 80 confirmed cases worldwide, with another 50 investigations pending and likely to be reported as global surveillance expands.
West and Central Africa Thousands of endemic cases are usually reported annually, but cases of monkeypox outside Africa are rare and largely travel-related. What characterizes this global outbreak is the high number of cases with no known travel source.
“The global spread is worrisome. It’s not something we’re particularly used to with monkeypox,” said Jason Kendracchuk, associate professor of viral diseases at the University of Manitoba and Canada’s chair of research for emerging viruses who has conducted research on monkeypox.
“What we’re seeing now is unprecedented. We have multiple geographic locations around the world reporting cases… What is the epidemiological link between these cases and is there anything related to changes within the virus?”
Watch | Officials are investigating two confirmed cases in Montreal:
Is monkeypox mutated?
There are two main strains or “strains” of monkeypox: the Congo strain – which is more severe, with a mortality rate of up to 10 percent – and the West African strain, which has a mortality rate of about one percent.
Transmission can result from close contact with respiratory secretions or skin lesions of an infected person, or from recently contaminated objects. Symptoms can include fever, severe headache, swollen lymph nodes, back pain, muscle pain, lack of energy, rash, and severe lesions.
It seems that the current strain spread globally is West AfricaBut genetic sequencing is currently underway in Canada and around the world to determine if he has any distinct genetic mutations.
“There is always this question, have things changed?” Kindrachuk said.
“What you’ll definitely hear over the next few weeks is a lot of information coming in from people who have been specifically looking at samples from these patients and determining whether or not anything is different — until now, we haven’t seen severe or fatal cases.”
The strain appears to be closely related to what circulated in West Africa in 2018, but more research is needed, says William Hanage, an epidemiologist at Harvard TH Chan School of Public Health and co-director of the Center for Infectious Disease Dynamics.
“It certainly behaves differently in the sense that it is much more prevalent,” he told CBC News. “Because until very recently, there were a few countries outside Africa that it was introduced to.”
“Obviously something different is going on here. Now, what makes this difference is currently unknown.”
Hanage said the current strain of prevalence in at least 11 countries including Canada appears to be more transmissible, with a Reproduction number It is likely higher than one, given that the global outbreak continues to grow of an unknown size.
But cases may also have been quietly spreading below the surface for months.
“Once the places started looking for it, they found it, which indicates that it is not spreading very quickly but has been around for some time and in relatively large numbers,” he said. “Once you start targeting your tests on those distinct pests, you start finding them.”
The genome sequence One of the first identified monkeypox cases in Portugal was uploaded Friday after the sample was received on May 4, but Hanage said it was “very reasonable” to suspect the outbreak “largely predates” that case.
“We don’t know the true number of cases, but I think it’s important to keep in mind that this could have been transmitted for months and gone unnoticed,” he said.
“Human behavior has also moved back and forth between some fairly extreme cases in the past few years, and we are now in a position where this virus will likely find it more easily transmitted.”
“How is it transferred?”
Canada’s top public health official, Dr. Theresa Tam, said Friday that genetic sequencing is currently being performed at the National Microbiology Laboratory in Winnipeg to confirm any further cases in the coming days and weeks.
“We don’t really know to what extent the spread has occurred in Canada. This is under active investigation,” she said during a news conference on Friday.
“We know so far that there are not many of these individuals associated with travel to Africa where the disease is commonly seen. So it is unusual… to see such a large number of cases reported in different countries outside of Africa.”
At the start of any virus outbreak, Tam said experts need to “take a broad view” to try to understand the ways the virus is transmitted, adding that much remains unknown about this “unusual situation”.
“It’s possible that there were some subtle chains of transmission that could have happened for a fair number of weeks, given the global situation we’re seeing right now,” she said.
“Most people have not traveled, so how does it move?”
The most important factor in determining whether an outbreak like this can be controlled, Hanage says, is whether symptoms occur before or after a person becomes infectious.
“If a person is contagious before they have symptoms, it is very difficult to control,” he said, “with smallpox viruses, classically, that is not the case. So a person gets rashes and at that point they become contagious.”
“At the moment, we don’t know that’s the case with this. But we have every reason to suspect that it will be but we still need to confirm that.”
Change in spread among humans
Another unusual characteristic of monkeypox cases that are currently spreading worldwide is the lack of direct transmission from animals to humans.
“There is very little evidence of human-to-human transmission, certainly outside of Africa,” Hanage said. “It’s as if this lineage has evolved the ability to pass from human to human. How? I don’t know. Where? I have no idea.”
Another concern, Hanage says, is any patients who inadvertently develop mild symptoms but are still contagious and may not realize they are at risk to others.
Monkeypox usually spreads through close contact and inhalation — although not as easily as viruses like SARS-CoV-2, says Angela Rasmussen, a virologist and researcher with the Vaccine and Infectious Diseases Organization (VIDO) of the University of Saskatchewan.
But she says it can also be spread by direct and indirect contact.
“This means that there are a lot of potential opportunities for it to be deployed in situations where people have been in close contact for a long time.”
Watch | Cases of monkeypox have been discovered in Canada amid a global outbreak:
‘Every reason to worry’ about containment
Rasmussen says there are many ways monkeypox outbreaks can be contained through traditional epidemiological measures such as contact tracing, isolating infected people, and isolating those who may have been exposed.
Failing that, she said, “we have a vaccine.” “We also have drugs that can be deployed that will definitely help with containment.”
Deputy Chief of Public Health Dr. Howard Ngo said Friday that since Canada halted smallpox vaccination campaigns in the early 1970s, those under 50 will not have any protection while the immunity of older Canadians is likely to be weakened.
“In general, the entire population is susceptible to monkeypox,” Ngo said during a press conference.
British health authorities took a bold step this week and moved to offer smallpox vaccines, which are considered somewhat effective against monkeypox, to some health care workers and contacts who may have been exposed – using so-called circular vaccination strategy.
“There is every reason to be concerned about containment capacity, not least due to the fact that the weight of containment will depend on vaccines and their very effective use,” Hanage said.
“The bigger the problem, the worse the situation we started from. So I think it’s not likely to be easy to contain, but I wouldn’t say it’s not necessarily containable. The sleeves and time to go to work.”
Canada has been very silent about its stockpile of smallpox vaccines, despite buying more than 30 million US dollars It is expected to be delivered last year in 2023. On Friday, Ottawa said it was “exploring” circular vaccination with the World Health Organization and UK health officials.
“One thing that is completely different from COVID is that we have a vaccine. We don’t necessarily have as much as we would like, but we do have a vaccine. We don’t have to worry about this particular future,” Hanage said.
“That doesn’t mean we got it where it needs to be, but it does mean that we’re starting from somewhere completely different.”
While Hanage says we are in a much better position compared to the beginning of the COVID-19 pandemic, the emergence of monkeypox outbreaks globally underscores the need for funding and to stay on top of earlier threats.
“Research has been underfunded for a long time,” he said. “I don’t think public health authorities have been paying much attention to it.” “And it just shows that if you turn your back on a virus it can jump up and bite you in the ass.”