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Researchers model how to contain Avian flu H5N1 in case of human-to-human transmission

sandramc — Fri, 27 Mar 2026 10:15:00 +0000

At this point, Avian flu H5N1 is thought to have very limited ability to transmit between humans, but a recent case in British Columbia with an unknown source of transmission has piqued the curiosity and concern of scientists, including 91��ɫ Professor Seyed Moghadas.

Did this lone case come about through transmission from an animal or another person, and if it was via human transmission, what methods will control its spread in the human population? Director of 91��ɫ’s Agent-Based Modelling Laboratory in the Centre of Excellence in AI for Public Health Advancement, Moghadas and a group of researchers used modelling to understand the best spread control measures should human-to-human transmission become possible.

“The idea was, let's evaluate some of the interventions that we usually implement at the very earliest stage of a disease outbreak or emerging disease, which we know very little about,” he says.

For the research, ",” published today in Nature Health, various scenarios from isolation to vaccination before or after a spillover event were modelled. It is one of only a few studies that have explicitly modelled outbreak dynamics following spillover into humans or the effectiveness of public health interventions in early and highly uncertain phases of virus development.

As a professor of computational epidemiology and vaccine science in 91��ɫ’s Faculty of Science, Moghadas and his colleagues were already collecting data on H5N1 cases in the United States when the Canadian case arose. Given the unknown nature of transmission, the team decided to pivot their work to look at what was happening in B.C.

“The case in B.C. was of particular interest for us because no definitive source of exposure was identified, including no direct contact with infected animals or known high-risk settings such as poultry farms,” says Moghadas. “Because of that, it came to our attention that maybe there is some sort of transmission going on between humans.”

As far as health and science experts know, H5N1 can only be transmitted among poultry and dairy cattle on farms, as well as through wild birds, and from these animals to humans, but sustained human-to-human transmission has not been established. The person from B.C., however, had no clearly identified exposure and even though human infection from animals is rare, avian influenza H5N1 is considered highly pathogenic and a potentially serious and evolving threat to global public health.

“This virus was first identified in 1997 in Southeast Asia. This kind of zoonotic virus essentially jumps from the bird or animal side to human side sometimes, mostly it circulates among wild birds,” says Moghadas. “There is no confirmation that human-to-human transmission happens as yet in North America.”

Seyed Moghadas

The virus has only been in North America since 2022, but surveillance monitoring for it began in 2003 and up until recently there have been close to 1,000 cases reported globally in humans and just under 500 deaths, although the number of cases could be higher because not all cases are likely reported or symptomatic. The virus has not only expanded its geographical range, but also the animal species it can infect.

“Evolution of influenza viruses of any type is always a challenge for humans. The flu virus is one of the very rapid mutating pathogens,” he says. The concern is it will mutate to be able to transmit between humans. How viable is it? How easily can it spillover from animals to humans, and how long could the potential chain of transmission from human-to-human become? These are still open questions.

“Quantifying that risk was important for us because that could also give us direction in terms of how bad the disease could be and what strategies will work to contain it,” says Moghadas. “We have very few measures in place or a strategy to deal with it at this point, given that the transmission between humans is not established.”

As it is an avian flu virus, it will likely require two doses of a similar vaccine to what was used during the H1N1 pandemic to reduce the risk and severity which often triggers a higher viral load.

The researchers used Abbottsford, B.C. as the location as it is a highly dense poultry farming area. The starting point is after a spillover has happened. “If a human became infected, how do we block this single individual to trigger a large outbreak? Or if the infection is going on between humans, can we block these chains and to what degree we can block them?” asks Moghadas. “What is the effectiveness of either self-isolation of symptomatic cases or vaccination of farmers or vaccination of farmers and their household members?”

Even with mitigation measures, someone in the farmer’s family could potentially be infected by the farmer and then transmit it to someone in the community.

The team evaluated two different types of vaccination strategies. One was reactive, which means that you trigger a vaccination program after a case has been identified somewhere. The second strategy was pre-emptive – individuals, such as farmers, are vaccinated before any case is identified.

What they found is that reactive vaccination has very limited additional benefits outside of self-isolation, but pre-emptive vaccination adds substantial additional benefits on top of self-isolation.

Should the virus be confirmed to be capable of human-to-human transmission, Moghadas says they want to limit the chain of transmission and minimize the risk of evolution of the virus to become more adapted to human conditions. For now, he says, when cases are identified, the person should self isolate immediately. For the authorized vaccine, it should be meted out quickly to target populations, but that could take several weeks to have population level effectiveness.

“Timely action is a critical part of controlling the spread. Self-isolation of symptomatic cases has a significant effect, but that comes with the caveat that we don't know if everybody who is infected will develop symptoms,” says Moghadas. “There could be potential asymptomatic cases we don't identify and by the time we do identify them, they've been already infecting others in the chain of transmission. This case in B.C. was particularly concerning because they could not find the source of infection.”

The concern is not only that the virus might be able to jump from animals to humans, but also the potential for it to mutate during early human transmission chains making it more adaptable to infecting humans. This underscores the risk of local outbreaks with global implications, he says.

“My research is all about evidence generation for governments, health-care providers and policymakers in public health organizations. We are generating evidence that can be used to at the very least limit the potential for this virus to become another pandemic,” says Moghadas.

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91��ɫ U led research sheds light on earliest days of Earth’s formation

egamulin — Wed, 26 Mar 2025 16:34:59 +0000

Faculty of Science prof used novel approach of applying fluid dynamics and chemistry to planetary sciences for modelling study published in Nature

Wednesday March 26, TORONTO – New research led by a 91��ɫ professor sheds light on the earliest days of the Earth’s formation and potentially calls into question some earlier assumptions in planetary science about the early years of rocky planets. Establishing a direct link between the Earth’s interior dynamics occurring within the first 100 million years of its history and its present-day structure, the work is one of the first in the field to combine fluid mechanics with chemistry to better understand the Earth's early evolution.

“This study is the first to demonstrate, using a physical model, that the first-order features of Earth’s lower mantle structure were established four billion years ago, very soon after the planet came into existence,” says lead author Faculty of Science Assistant Professor in the Department of Physics and Astronomy at 91��ɫ.

The mantle is the rocky envelopment that surrounds the iron core of rocky planets. The structure and dynamics of the Earth’s lower mantle play a major role throughout Earth’s history as it dictates, among others, the cooling of the Earth’s core where the Earth’s magnetic field is generated.

Boukaré – originally from France – worked with research colleagues from his former institution, Université Paris Cité's James Badro and Henri Samuel, on the paper, , which was published today in Nature.

Boukaré says that while seismology, geodynamics, and petrology have helped answer many questions about the present-day thermochemical structure of Earth’s interior, a key question remained: how old are these structures, and how did they form? Trying to answer this, he says, is much like looking at a person in the form of an adult versus a child and understanding how the energetic conditions will not be the same.

Artistic view of Earth’s interior during mantle solidification in the first hundreds of millions of years of Earth’s history. Gravitational segregation of dense, iron-rich magma (in orange) likely formed a basal magma ocean atop the core, that can explain the present-day structure of the lower mantle.

“If you take kids, sometimes they do crazy things because they have a lot of energy, like planets when they are young. When we get older, we don't do as many crazy things, because our activity or level of energy decreases. So, the dynamic is really different, but there are some things that we do when we are really young that might affect our entire life,” he says “It’s the same thing for planets. There are some aspects of the very early evolution of planets that we can actually see in their structure today.”

To better understand old planets, we must first learn how young planets behave.

Since simulations of the Earth’s mantle focus mostly on present-day solid-state conditions, Boukaré had to develop a novel model to explore the early days of Earth when the mantle was much hotter and substantially molten, work that he has been doing since his PhD.

Boukaré’s model is based on a multiphase flow approach that allows for capturing the dynamics of magma solidification at a planetary scale. Using his model, he studied how the early mantle transitioned from a molten to a solid state. Boukaré and his team were surprised to discover that most of the crystals formed at low pressure, which he says creates a very different chemical signature than what would be produced at depth in a high-pressure environment. This challenges the prevailing assumptions in planetary sciences in how rocky planets solidify.

“Until now, we assumed the geochemistry of the lower mantle was probably governed by high-pressure chemical reactions, and now it seems that we need to account also for their low-pressure counterparts.”

Boukare says this work could also help predict the behaviour of other planets down the line.

“If we know some kind of starting conditions, and we know the main processes of planetary evolution, we can predict how planets will evolve.”

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91��ɫ is a modern, multi-campus, urban university located in Toronto, Ontario. Backed by a diverse group of students, faculty, staff, alumni and partners, we bring a uniquely global perspective to help solve societal challenges, drive positive change, and prepare our students for success. 91��ɫ's fully bilingual Glendon Campus is home to Southern Ontario's Centre of Excellence for French Language and Bilingual Postsecondary Education. 91��ɫ’s campuses in Costa Rica and India offer students exceptional transnational learning opportunities and innovative programs. Together, we can make things right for our communities, our planet, and our future.

Media Contact:

Emina Gamulin, 91��ɫ Media Relations, 437-217-6362, egamulin@yorku.ca

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Testing rate and contact tracing key to successful re-opening of Ontario

roshanp — Thu, 21 May 2020 12:45:10 +0000

TORONTO, May 21, 2020 – Enhanced testing and contact tracing for the coronavirus in Ontario could allow physical distancing measures to be relaxed, while keeping the reproduction ratio under one and preventing a second wave of infections, says corresponding author of a new modelling study Distinguished Research Professor of 91��ɫ’s Faculty of Science.

The de-escalation would include three phases – a re-opening of workplaces, a resumption of public events and activities, followed by the opening of schools. The researchers modelled the requirement for testing, contact tracing and quarantine for each phase.

To be successful in the first two phases, the current time for diagnosis needs to be maintained and almost 60 per cent of exposed contacts would have to be traced, quarantined and isolated. Although, if some level of social distancing is maintained, that could counter any decrease in quarantining.

In the third phase, the researchers found that 70 per cent of exposed contacts would need to be isolated to avoid a rebound, a value they say is unrealistic. The use of masks and personal protective equipment during de-escalation, however, could be an important tool in helping to prevent a rebound.

“Our analysis can help inform public health and policy makers on best future actions and interventions to control the outbreak while relaxing physical distancing,” says Wu, director of the Advanced Disaster, Emergency and Rapid Response Simulation Program.

The researchers looked at different possibilities and scenarios involving de-escalation of the current physical distancing and isolation rules for all of Canada, but particularly in Ontario. The province closed schools on March 14 and declared a state of emergency on March 17 with the closure of non-essential workplaces as of March 24.

The study estimated the effectiveness of interventions in terms of contact rate, probability of transmission per contact, detection rate, and proportion of isolated contacts. They concluded that a feasible de-escalation approach is to reverse the steps taken that led to most workplace and school closures.

In the future, the researchers say a transmission model involving age-specific contact mixing could be used to determine logistic implementations of a wider range of de-escalation strategies that would be dependent on a person’s age and the setting, whether a school, workplace, the home or community.

The research was published in the journal

Find out more about how 91��ɫ is creating positive change in the COVID-19 pandemic .

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91��ɫ champions new ways of thinking that drive teaching and research excellence. Our students receive the education they need to create big ideas that make an impact on the world. Meaningful and sometimes unexpected careers result from cross-disciplinary programming, innovative course design and diverse experiential learning opportunities. 91��ɫ students and graduates push limits, achieve goals and find solutions to the world’s most pressing social challenges, empowered by a strong community that opens minds. 91��ɫ U is an internationally recognized research university – our 11 faculties and 25 research centres have partnerships with 200+ leading universities worldwide. Located in Toronto, 91��ɫ is the third largest university in Canada, with a strong community of 53,000 students, 7,000 faculty and administrative staff, and more than 300,000 alumni. 91��ɫ U's fully bilingual Glendon Campus is home to Southern Ontario's Centre of Excellence for French Language and Bilingual Postsecondary Education.

Media Contact:

Sandra McLean, 91��ɫ Media Relations, 416-272-6317, sandramc@yorku.ca

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