As much of the world is still reeling from the outcome of the recent U.S. presidential election, many within the scientific community have been left with feelings of uncertainty about their futures as the President-elect has a seemingly unabashed lack of scientific knowledge. Nowhere is this more apparent than Mr. Trump’s views concerning climate change, which are alarming, to say the least.
“It is likely [that] this lack of scientific understanding will cascade to other branches of governance beyond just climate change,” stated Ildiko Dunay, Ph.D., associate professor in the department of neuroscience, microbiology, and immunology at Otto-von-Guericke University in Magdeburg, Germany, who also incorporated sentiments from her laboratory group into her discussion. “The President-elect will likely be less prepared to deal with potential new disease outbreaks, negatively impact education and prevention of potential new disease spread, and will also amplify the climate change situation with legislation that supports drilling for oil or [the] burning of fossil fuels.”
“I think the biggest impact of disregarding or denying climate change, at a national leadership level, is that this could lead to an undervaluing of science and less funding for scientific investigators to understand the drivers of climate change, how climate change may impact tropical/parasitic disease transmission, and how disease transmission may be better predicted or abated,” added Douglas Norris, Ph.D., a professor in the department of molecular microbiology and immunology at Johns Hopkins Bloomberg School of Public Health and Johns Hopkins Malaria Research Institute. “Effective disease control and prevention requires a solid scientific base—not just to create tools like vaccines or drugs, but to develop a thorough understanding of why some tools work in some places and not others, of how to better educate the non-scientists, the policymakers, etc.”
Breaking the Ice
The impact of climate change goes far beyond the extensively reported melting of Arctic ice and rises in catastrophic weather phenomena. The often less described ill-effects of climate change stem from the surges in disease, many of which had been previously confined to warmer or more tropical regions of the globe. As temperatures continue to increase unassuaged, numerous illnesses are beginning to encroach into naïve regions or reemerge within areas where they were long thought to be eradicated.
“Something is brewing with the rise of Zika, dengue, chikungunya, and Chagas disease in the western hemisphere, in southern Europe with malaria in Greece, schistosomiasis in Corsica, dengue in Portugal, West Nile virus, and chikungunya in Italy, Spain, and southern France, it’s very troublesome,” remarked Peter Hotez, M.D., Ph.D., dean of the National School of Tropical Medicine and professor of pediatrics and molecular virology & microbiology at Baylor College of Medicine.
Yet, over the years much of the U.S. has been relatively protected from increases in vector-borne diseases—in part due to our geographical location, but primarily owing to our modern infrastructure.
“The primary protection for people living in the U.S. is likely the quality of life we have, both for us and our domestic animals,” noted Dr. Norris. “We tend to spend most of our time inside, in air-conditioned and well-screened homes. Therefore, our exposure to mosquitoes and ticks that may transmit pathogens is relatively low.”
Complacency, though, will lead to outbreaks that could be detrimental to various populations in the U.S. People living in southern states and border towns will likely be at ground zero for the infiltration of a variety of infectious diseases that are destined to become more prevalent if climate trends continue.
“We’re already seeing the emergence of vector-borne diseases in Texas, Florida, and the Gulf Coast region,” Dr. Hotez stated. “For instance, our scientists at the National School of Tropical Medicine at Baylor College of Medicine have found the transmission of dengue, Chagas disease, murine typhus, leishmaniasis and other neglected tropical diseases all around Texas—even within Houston. A big question is whether that is truly due to climate change or other factors as well, such as human migrations and new shifts in poverty.”
Dr. Hoetz makes an important point, as the connection between the spread of disease and climate change is not nearly as straight forward as many might presume. For example, Southeast Asia is home to some of the most rampant, drug-resistant malaria in the world. Yet, sporadically dotted throughout the region are areas devoid of malaria transmission. Most of these zones, such as Singapore or the tiny nation of Brunei, have largely eliminated the disease, thanks in no small part to increased wealth and industrialization—underscoring the importance of appropriate public health infrastructure.
Even the Smallest Disease Can Change the Course of the Future
Even in places with robust public health surveillance systems, such as the U.S., there are examples of diseases that have slipped under the radar and are continuing to expand their transmission territory, due to the impact of climate change. Lyme disease, a bacterial infection spread through the bite of the deer tick, is an ideal example of a vector-borne illness that has capitalized on climactic changes, though not within the previously mentioned subtropical regions. In the past several years, Lyme disease has begun its Napoleonic trek toward colder zones north into places like Maine and southern Canada.
“It is important to point out that despite the fear of Zika or dengue in the U.S., Lyme disease is our most frequently reported vector-borne disease with 30,000 cases reported annually,” Dr. Norris remarked. “And it is estimated that this is under-reported by up to 10-fold.”
When confronted with the idea of prognosticating which disease is likely to become most burdensome, due to changes in global temperatures, many scientists are understandably hesitant to answer definitively. Research on a number of parasitic, microbial, and viral pathogens has only just been greenlighted within the past few years—making predictions about their behavior difficult. Moreover, investigators are still working to understand the complex relationships between the environment and disease transmission rates, in addition to the host of other factors that could significantly alter a disease endemicity.
“I think we are still trying to understand the potential impacts of climate change on vector-borne diseases,” Dr. Norris said. “Additionally, it is hard to pull apart the drivers in changing patterns of disease transmission.”
Though our panel did agree that most diseases, especially the ones for which they dedicate much of their research focus, will be impacted by climate change—most likely leading to increased illness rates for humans and livestock. Dr. Dunay and her laboratory, who study the parasite responsible for causing Toxoplasmosis, believe that “areas which experience a warmer climate should expect to see increases in Toxoplasma transmission and virulence.” Dr. Dunay noted that while current Toxoplasma transmission is fairly widespread among Europe populations, in the warmer climates of South America, such as Brazil, for instance, virulence seems to be much greater and could expand north given ideal climate conditions.
Additionally, for schistosomiasis—a parasitic infection caused by freshwater flatworms—Dr. Hoetz has noticed some significant changes in transmission patterns. “We’re seeing the return of urban schistosomiasis to Venezuela, and now it’s in Corsica, off the coast of France, which is unprecedented.” However, Dr. Hoetz was quick to note that climate change is not the only variable as “political destabilization, economic downturns, urbanization, and new human migrations could also be contributory factors.”
Amid Caution and Uncertainty, Hope Remains
The scientific community is in strong agreement that climate change represents a persistent threat to many species’ survival. Much of that risk stemming from, as discussed here, increases in the prevalence and territory of various infectious diseases. Yet, there are many outside of the science disciplines that remain unconvinced of the extreme danger posed by this global issue. Scientists need to do a better job convincing politicians and policymakers that it is in the best interest of their government and their people to consider the facts with all due seriousness.
“I think the future of all scientific research, especially for diseases potentially impacted by climate change, depends substantially on sustained support,” Dr. Norris stated. “Such support will depend on our national leadership and the global community understanding the value of scientific research in determining our future state and provide the necessary funding to achieve those ends.”
Yet, sometimes the best way to help others is by looking inward. Which might be the necessary approach the scientific community as a whole should look toward, as Dr. Hoetz pointed out in his concern that “the academic world and its incentives are in silos so that we don’t have many virologists and epidemiologists speaking to scientists and academics in other disciplines, i.e., earth science, economics, political science, so there’s no framework for solving complex multidisciplinary problems.” Perhaps, once scientists can become more inclusive among their own disciplines, they can hope to effectively communicate the importance of these ideas to the non-science public.
Yet, scientists wouldn’t be as committed to their research if they didn’t have a deep-rooted sense of being only one experiment away from a breakthrough that can effect positive change. It is what drives them and allows them to continue even amidst bleak outlooks for the future.
“I am optimistic,” Dr. Dunay concluded. “I believe science can always persevere in the face of adversity, and we usually make the greatest scientific leaps when presented with our greatest threats.”