Thirty years after the 1994 genocide against the Tutsi, Rwandan-born researchers Glorieuse Uwizeye and Egide Kalisa are driving recovery in their homeland and shaping global perspectives on trauma and environmental health.
In 1994, Rwanda suffered a hundred days of genocide. Members of the Hutu majority targeted the Tutsi minority, killing an estimated one million people.
Thirty years later, Rwanda is in many ways a different country. It put in place a justice and reconciliation program that brought perpetrators to trial, but also attempted to heal the rift in the population. It ended official recognition of different ethnic groups.
But the country still faces problems from those years, and people are still suffering the effects of trauma—some of whom were in the womb when the genocide occurred.
And it faces other problems common to many other developing African countries, including elevated levels of air pollution.
Two Western University researchers originally from Rwanda are conducting research they hope will help their country confront and overcome these pressing challenges.
I.
UNCOVERING HIDDEN TRAUMA
Glorieuse Uwizeye was a high school student when the Rwandan genocide happened. She and her immediate family managed to survive by hiding at home.
Today, Uwizeye is a professor of nursing at Western. She studies the intergenerational effects of trauma—how trauma experienced by a mother can go on to affect children born after the experience is over.
“Rwanda is a country that has renewed itself. It is a country that is really being transformed after the genocide, where people are progressing in life, and it’s a safe country. But the effects of genocide are still lingering, 30 years later,” she says.
She has found that children of survivors who were conceived in the country while the genocide was occurring have greater physical, mental and emotional problems than those conceived by Rwandans who were living outside of the country at the time of the genocide. And those who were conceived by rape have even more problems than the others.
“These are the people who need support in order to be able to achieve the same quality of life as anybody else,” Uwizeye says.
When Rwanda was colonized by Europeans in the late 19th century, the population consisted of a Hutu majority and a politically dominant Tutsi minority, along with a smaller number of forest-dwelling people known as the Twa.
German and Belgian colonizers hardened the categories, defining them in racial terms and backing a Tutsi ruling class. After decolonization, political conflicts continued. In 1994, Hutu extremists, launched a genocide in response to plans for a new unity government, with the military, organized militias and ordinary Hutus attacking Tutsis.
Uwizeye was a member of the Tutsi minority, and a high school student studying nursing. By the time the genocide was over she had lost over 100 members of her extended family. But she and her immediate family survived.
Afterwards, she went back to high school and attended nursing school at the University of KaZulu Natal in South Africa. When she came back, she had a master’s degree in mental health.
During breaks she worked with her mother’s non-profit Association Mwana Ukundwa, or Association of the Beloved Child, which helped children who had survived the genocide, and put her in touch with the problems survivors were experiencing.
“After my master’s degree, I started wanting to advocate for survivors, especially because there were all these social, economic and mental health factors that were not given enough attention,” she says.
As part of her work, she interviewed women who had been raped during the genocide, and then given birth.
“The children were seen as children of perpetrators, so there was no support for them. Then the women would feel like they were being doubly punished, because of their rape experience, and because they were abandoned to care for the children.”
She felt there were gaps in the research being done, which didn’t always take into account the concerns of the survivors. Determined to address this, she earned a PhD from the University of Illinois Chicago and embarked on research projects of her own.
Of course, the genocide was traumatic for everyone who lived through it. But Uwizeye believed the trauma was especially damaging to children who had been in the womb when it was occurring. The trauma experienced by the mother, she suspected, had affected the unborn children.
She found 91 adult children of survivors who had been in the first trimester during the genocide, an especially important time in fetal development. By the time of her first study, these survivors were 24 years old.
Thirty of them had been conceived by men who raped their mothers; another 31 were born to mothers who had lived through the genocide but not been raped; and 30 were born to Rwandans living outside of the country.
All of them answered questionnaires about their physical and mental health, and it became clear that having been in the womb during the genocide caused problems for many of them.
Compared to those whose mothers had not lived through the genocide, the survivors’ children had worse mental and physical health overall, higher scores for post-traumatic stress disorder (PTSD), and worse anxiety, depression, problems with pain, and sleep disturbances.
Those who had been conceived by rape had even more symptoms of depression and PTSD, and worse problems with pain than those who were not conceived of rape.
Why should these children be suffering from the trauma their mothers experienced? There are a number of possible reasons.
First, it’s known that conditions during pregnancy can affect the child. This was shown dramatically in the Dutch Hunger Winter Study of children born to mothers who were malnourished in 1944 because of the Second World War, Uwizeye says. Those children grew up to have higher rates of obesity and heart disease.
One theory is that the fetus was adapting to signals it was about to be born into a world of scarcity and adapted itself to use food more efficiently. When they were born into a world without famine, those adaptations made them obese instead.
Likewise, children about to be born into a dangerous and traumatic world might undergo mental and emotional changes that would help them survive, such as being more cautious and anxious. But those adaptations could also come at a cost, especially when the danger is gone.
Regardless of whether higher anxiety is adaptive, researchers have some idea about how it might be passed on.
In one paper, Uwizeye points out that responses to stress, including anxiety, are controlled by the interactions among the brain’s hypothalamus and the pituitary and adrenal glands. This system begins developing in the embryo, and it’s affected by the levels of the stress hormone cortisol in the mother’s system. Children born to mothers who experienced more stress have been shown to react more strongly to cortisol than others.
In her most recent work, Uwizeye also showed the longer the children were exposed to the genocide in the first trimester, the higher their anxiety and depression were. But this only happened in the children who weren’t conceived by their mothers’ rapists.
Among the children conceived by rape, their scores were equally poor no matter how long they had been exposed in the womb.
It seems likely, Uwizeye says, that for their mothers the stress didn’t go away when the genocide was over. Instead, the mothers continued to feel stress throughout the pregnancy because of shame and stigma.
The children of rape survivors also faced worse conditions after they were born, Uwizeye says. They were often resented by their mothers and rejected by their communities.
“Somebody would come and kill your father, kill your brothers, kill your family and then rape one of the women. These children are being raised by the mothers, and these are the victims of the child’s father, and sometimes they are in the community of survivors,” she says.
Uwizeye is also looking at the survivors’ children’s epigenetic markers—that is, the molecular signals that determine whether certain genes are turned on and off. These markers are changed by the environment, including the environment in the placenta.
So far, she has found that children of survivors, who are 30 now, seem suffer from accelerated aging, which could put them at greater risk for early onset of chronic diseases.
“I wanted to look at those biomarkers that continue to be transmitted through the generations and advise on intervention that will make sure there is health equity, that the descendants of survivors achieve the highest quality of life they deserve, despite what has happened to their parents,” she says.
One of the things she tries to ensure is that participants in her studies aren’t further traumatized by the research. In designing her studies, she says, she works with Western experts on trauma- and violence-informed approaches to research.
“Rwanda has really shown a high level of resilience, and the people don’t always think about the genocide. So then the challenge was, how do I go back to people who are still strong and tell them, ‘Oh, you are carrying some effects of the genocide’?”
Uwizeye says she accepted the position at Western in 2022 because she wanted to continue working with Rwandan survivors at a leading research university that would fully support her efforts.
“I love Canada. I love the people here, and I think it’s a good place to be, in particular here at Western. I have a really good group of colleagues. They are so supportive,” she says.
In addition to what she describes as “incredible support” from Western, Uwizeye has received a grant from the Social Sciences and Humanities Research Council to conduct a long-term study on the adult quality of life of Rwandans prenatally exposed to genocidal violence, as well as the intergenerational impacts on their children.
She hopes the lessons learned from Rwanda can also benefit Canada, a country dealing with its own history of colonialism and violence, and support immigrants who have experienced violence in their homelands.
In the meantime, she says Rwanda is a transformed country where ethnic differences are emphasized less and people work together peacefully. Nevertheless, the people she studies still deserve help.
“I think it is important, even when a population is smaller, to pay attention to their lives, because as a minority population, we get lost into the bigger population. Even if a problem is not big enough to affect everybody, it is still affecting our population, a population that needs to be paid attention to.”
II.
CLEARING THE AIR
While Egide Kalisa was a child growing up in Rwanda, both of his parents died of what was likely a respiratory illness.
He was raised by his siblings, and as he got older he knew two things—he wanted to be a teacher like his father and he wanted to do something about the air pollution he suspects contributed to his parents’ deaths.
Today, Kalisa is a professor of epidemiology and biostatistics at Western’s Schulich School of Medicine & Dentistry. He studies the origins and effects of air pollution in his home country and around the world. And he works on projects to try to prevent pollution and counter its effects on health.
“After losing my parents, I thought, if someone can do something, why not me? It has pushed me to really focus on my goals,” Kalisa says.
Globally, air pollution is the greatest cause of premature death worldwide, contributing to disease like pneumonia, lung cancer and chronic lung disease.
Rwanda and Africa in general face an especially big problem. The continent has the fastest growing population in the world, with the number of people set to double by 2050. With that growth comes sources of air pollution, including larger cities, more industry and more motor traffic.
Although studies on air pollution in Africa are still lacking, those that have been done show it exceeds limits recommended by the World Health Organization in many regions, says Kalisa. Even routine air monitoring isn’t common.
“We still lack data in most of Africa. So we are trying to build networks of robust, inexpensive sensors,” he says. The sensors would track air quality over time and give researchers the data they need to understand the problem.
After earning a bachelor’s degree in environmental conservation at the University of Rwanda, Kalisa was granted a scholarship to the University of Birmingham, where he earned a master’s in air pollution management and control.
From there he went to the Auckland University of Technology for his PhD, where he studied how pollution travels globally, and how air quality can be forecasted. The work included studying air quality levels in New Zealand, Japan and Rwanda.
He notes that although we often think of pollution as a problem within a country’s borders, in fact it is international.
“Pollution doesn’t require a visa. Pollution can travel from one location to the other.”
When Kalisa finished his PhD, he came to Canada to do a postdoctoral fellowship at the University of Toronto, and then worked for two years as a research scientist for Environment and Climate Change Canada. He joined Western in 2023.
In a 2018 study, he confirmed pollution levels in Africa were often much higher than recommended, exposing many Africans to a higher risk of disease.
He found that in rural areas, air pollution tended to come largely from wood fires, frequently used for cooking. In cities the main source was gasoline and diesel vehicles. Motorized vehicles are an especially bad problem because they tend to be older and more poorly maintained than in more developed parts of the world, so they pollute more.
Much of Kalisa’s lab research focuses on understanding the exact composition and sources of pollution.
In the big picture, researchers tend to be concerned about tiny particles that hang suspended in the air and are easily inhaled. They’re particularly worried about particles under about 10 micrometers, especially those under 2.5 micrometersas they can easily penetrate the lungs.
Often simply understanding the overall level of pollution is enough to know the air is bad to breathe. But much of Kalisa’s work is also concerned with the composition of the particles.
They can include a number of toxic compounds, including some that are carcinogenic. And they can also include biological material, such as disease-causing bacteria and fungi.
“It’s really hard as these are two totally different fields,” he says. One requires using techniques like mass spectroscopy to recognize the chemicals in a sample. The biological elements have to be classified using DNA sequencing.
Another part of his research examines the possible synergistic effects different combinations of pollutants can have, each potentially multiplying the harm of the other.
Some of his recent work has focused on air pollution school children are exposed to. Pollution in schools, he says, can affect not only overall health, but also cognitive ability, academic performance and school absences.
Schools in Rwanda typically rely on natural ventilation, so air isn’t filtered. And schools are often situated near main roads, so are exposed to pollution from vehicles.
In one study he found a surprising amount of air pollution was caused by cars dropping off and picking up students. Pollution levels at the schools could double during those times.
“I found there’s significantly high pollution from the cars idling at the school. If you look at the concentration, it is quite alarming in the morning. It’s higher than the concentration you could measure on the 401 highway in Ontario,” Kalisa says.
Unfortunately, he was working on some of this research during the worst days of the COVID-19 outbreak, when schools were temporarily shut down. But he was able to use the opportunity to study the decrease in air pollution levels from reduced traffic activity.
He also had data from Rwanda’s “car-free” days, the two Sundays out of every month when Rwandans are discouraged from driving.
“I found on a car-free day, the air pollution can be decreased by up to 30 per cent, and then that reduction can indirectly result in several million dollars in health care savings,” he says. The reduction in hospital bills, he says, comes from reduced pollution causing fewer diseases over time in the population.
Kalisa says he is just as interested in finding solutions to the problems as he is in research for its own sake. He says he wants to make a difference for Rwandans and others.
“I was thinking that just publishing a paper, that is not enough. How can I use my work to also propose a solution?” he says.
Partly for that reason, Kalisa launched a pilot program called HumekaNeza, or Breathe Easy, in two schools in Rwanda’s capital city of Kigali.
Kalisa provided workshops to teach children the science of air pollution. And he gave them low-cost sensors that can detect the quality of the air both in school and at home.
At the schools, he also instituted a system using green and red flags to indicate when the air quality made it unsafe to play outdoors. He enlisted students to plant trees to create a barrier between schools and roads and will study how much difference it makes for air quality. And he gave students tips on how to encourage their parents to turn off their cars during school pickup and drop off.
Other work includes a project to see if replacing diesel school buses with electric buses can improve air quality at the schools, in both Rwanda and Ontario.
He’s also studying how to use air purifiers in African classrooms, and assessing the effects on blood pressure, lung function and academic performance.
Kalisa says Western has been a good fit for him and his research, especially because the university supports his interest in research abroad.
“Western has strong international collaborations, which has been very important for me.
“I feel I’m a global citizen. Especially when I’m teaching the global health of air pollution, this is not an issue related to only Canada or Rwanda. It’s a global problem.”
