Heralding from Strasbourg, France, Dr. Roenick P. Olmo, Green College’s first French Scientist in Residence, thrilled his audience with a new way of looking at the mosquito—one of the world’s “deadliest” animals.
Dr. Roenick P. Olmo’s diverse educational background includes a PhD in bioinformatics from the Universidade Federal de Minas Gerais in Belo Horizonte, Brazil, and the completion of postdoctoral study at the Institut de biologie moléculaire et cellulaire (IBMC) in Strasbourg, France. In October 2023, Roenick became an associate researcher in the CNRS UPR9022 unit at the IBMC/Strasbourg where he continues his research on the various dimensions of the mosquito’s natural, yet intricate molecular resistance to virus infections. Roenick studies the links between the mosquito’s anthropophilic behaviour (i.e. the mosquito’s attraction to humans as a primary food source) and immunity, and the development of strategies intended to reduce the transmission of mosquito-borne pathogens. Currently working in collaboration with Dr. Benjamin Matthews’ lab in the University of British Columbia’s Department of Zoology, Roenick seeks to explore the connection between mosquito olfaction and immunity during his time at UBC.
Earning the title of “world’s deadliest animal” due to their capacity to transmit viruses from and between creatures—including humans—Roenick’s talk highlighted the Aedes aegypti species of mosquito as the major transmitter of viruses such as dengue, Zika, and chikungunya. Although originating in Africa—where the Ae. aegypti aegypti subspecies first developed an affinity for humans—the slow, climate change-aided spread of the species across the planet has increased the geographic presence, and thus threat of mosquito-borne diseases globally. Although this suggestion of impending biological, environmental, and social danger threatened to send the room into an anxious stupor, Roenick was quick to counter somber reality with a uniquely scientific optimism. Not only were we encouraged, through his passionate asides, to marvel at the complex physical beauty of the mosquito itself, but we were also introduced to the various mitigation strategies that Roenick and his lab are actively working on to reduce the transmission and expansion of mosquito-borne viruses.
Starting, with his audience, at the beginning, Roenick first traced the intertwining historical and societal patterns associated with the spread of mosquito-transmitted viruses. There are two types of transmission cycles, he explained: the Urban Cycle, which occurs when the mosquito bites a human being, and then transmits the virus to a new person; and the Sylvatic cycle, which occurs when a mosquito bites an animal and becomes infected, then bites and thus infects a human. Over time the African A. aegypti formosus mosquito evolved into the A. aegypti aegypti mosquito, which displays behavioural preference for feeding on humans. The spread of these mosquitoes to the Americas was deeply intertwined with European colonial projects, such as the trans-Atlantic slave trade. Roenick noted how the Portuguese slave trade, for example, brought mosquitoes carrying malaria and yellow fever to South America, in turn deeply impacting Indigenous populations with no prior natural immunity to the viruses. Similarly, the growth in global commerce relying on new rice crops from Asia and resultant modification of the land increased environments for mosquitoes to flourish. Central to these examples, for Roenick, is the realization that everything is connected—politics, economics, climate, environment, biology, and society. Take, for example, recent observations of the tiger mosquito’s (Aedes albopictus) increased resistance to colder temperatures. Paired with increasing global temperatures and global shipping routes, North American environments grow increasingly appealing for tiger mosquito reproduction and thus transmission. Moreover, Roenick noted how mosquitoes evolve alongside the virus they carry such that a single mosquito could be infected with multiple different viruses that, in turn, could lead to the appearance of new diseases in global human populations.
In light of these observations, Roenick’s work lies at the crux of understanding and manipulating transmission to reduce the potential for viral outbreaks. Amidst this sobering data, Roenick outlined how, in order for an outbreak of mosquito-borne virus to occur, multiple conditions must align: the climate must be suitable for vectors of transmission (i.e. mosquitoes), there must be human exposure to the vectors, the parasite must be introduced and cause infection, and transmissibility (as a facet of human susceptibility) must occur. Roenick’s approach to prevention lies in the disruption of these conditions; as more barriers are introduced, prevention, and its longevity, increases. More specifically, he targets human exposure and transmissibility. For the former, outbreak prevention is connected to the development of vaccines, such as current vaccine trials for dengue and chikungunya. For the latter, vector control may entail the elimination of mosquitoes and of breeding sites. However, there is no clear-cut solution.
Taking up this complicated approach, in the latter portion of his talk Roenick outlined various methods currently being researched in response to these conditions. For example, mosquito repellents require specific targets, and while they may reduce the number of mosquitoes for a short period, over time the creatures increase their resistance. Moreover, chemical insecticides and repellents are linked with a host of environmental impacts that must be considered. Another potential transmission-reduction method is the Sterile Insect Technique, which captures male mosquitoes (that don’t bite) and alters their DNA to generate infertility. Yet, Roenick noted, these high cost, high effort initiatives are not feasible for poorer countries. Within this field of current research, Roenick’s interest lies most strongly in the manipulation of the mosquito’s olfactory signalling. By increasing the mosquito’s sensitivity to novel repellents or editing the mosquito’s genes such that mosquitoes can no longer use their sense of smell to locate targets, transmissibility is largely decreased. Strategies that involve the modification of the mosquito’s gene drive emerge as the most sustainable option, Roenick argued, both financially and ecologically, because they rely on the reintroduction of the altered mosquito into the population, to procreate and thus increase the presence of natural resistance in mosquitoes.
Why might non-specialists care about his project and research on the oft-maligned mosquito? One of the most striking statistics that Roenick centralized in his talk is the rapid increase in reported cases of dengue infection, which jumped from 6 million cases in 2023 to 14 million in 2024. Roenick also emphasized how each previous prediction model failed to accurately predict the sheer number of cases reported. Situating his research on the pulse of a highly relevant and rapidly shifting biological and social climate, Roenick closed his talk with an important return to balance. While it might seem, in the face of the looming threat of mosquito-borne viral transmission, like an easier solution to suppress and eliminate the population of mosquitoes, Roenick is an advocate for alteration rather than eradication. The presence of mosquitoes ensures environmental equilibrium, he noted. As he reminded his audience: nature abhors a vacuum. So, if they are removed, what possibly greater threat will replace them?
Although Roenick did not stray away from the oftentimes harsh public health reality on which his research relies, he closed his talk with a careful tone of optimism. The design of surveillance plans and updated models for outbreak protection are key factors in a multidirectional approach, he argued; if factors such as viral surveillance, effective insecticide usage, population control, and increased pathogen blockage in the vector are mutually sustained, then the potential for and occurrence of outbreaks can be greatly reduced. But this can only happen if governments fully recognize the urgency of this kind of work.
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Roenick was in residence as the Visiting Scientist from France at Green College from September to December, 2025. His residency was co-sponsored with the Cultural and Scientific Office of the French Embassy in Vancouver, Canada.
Post by: Mackenzie Ashcroft, Green College Content Writer and Resident Member.