08
Oct
Common Fungicide Causes a Decrease in Antioxidant Responsible for Defense Against Diseases like COVID-19
(Beyond Pesticides, October 8, 2020) Research from the University of Wisconsin—Madison (UWM), suggests that fludioxonil—a commonly used agricultural fungicide—decreases the human body’s ability to defend itself against illnesses, like COVID-19, and promotes disease permanency. Tristan Brandhorst, a Ph.D. scientist at UWM, notes that a pesticide-induced reduction in the antioxidant glutathione could be responsible for this lack of bodily defense against disease. Although many studies examine how pesticides adversely affect the human body (i.e., cancer, respiratory issues, etc.), very few studies assess how pesticides reinforce chemical disruption patterns that reduce levels of vital chemicals needed for normal bodily function.
The steady rise in U.S. pesticide use, including disinfectants, threatens animals and humans, as exposure to indiscriminate dispersal of pesticides cause a whirlwind of health risks. As the total U.S. COVID-19 cases rise above 7.5 million, global leaders need to understand extensive pesticide spraying is not a viable solution to prevent illness and causes more chronic harm from exposure in the long run. Dr. Brandhorst stresses the need for proper reevaluation of pesticide risks stating, “The issue needs more study, [and] might also warrant a reworking of how [the U.S. Environmental Protection Agency] evaluates pesticides.”
Amidst the outbreak of SARS-CoV-2 (COVID-19), the global demand for pesticides, including disinfectants and sanitizers, has increased substantially as a means of preventing illness in domestic and community settings. Additionally, the increasing pervasiveness of moist environments from severe weather events like hurricanes increases the amount of mold and mosquito pests in some areas, causing higher inputs of fungicides and insecticides to combat the issue. However, exposure to these toxic pesticides can weaken the body’s immune response to illnesses, creating an environment for underlying condition (like respiratory issues such as asthma, or endocrine disruption problems like diabetes) to flourish among vulnerable individuals.
In 2019, Dr. Brandhorst (in the lab of Bruce Klein, Ph.D. at the University of Wisconsin–Madison and UW School of Medicine and Public Health) led a research study to discover the mode of action (or ability to cause harm) fludioxonil has on fungi. An initial 2018 analysis pointed to the uncertainty about how fludioxonil causes fungi cell death, claiming that this ambiguity merits a reevaluation by the U.S. Environmental Protection Agency (EPA) of its potential impacts on non-target organisms. However, Dr. Brandhorst recently discovered that the chemical causes metabolic shock to fungi, hindering glucose transport across the cell membrane. Additionally, further analysis finds that exposure to fludioxonil decreases glutathione levels in non-fungal cells, promoting “the ability of [the fungicide] fludioxonil to act on a sugar-metabolizing enzyme common to all cells, and to produce the damaging compound methylglyoxal.”
Although the U.S. Environmental Protection Agency (EPA) deems fludioxonil safe for use, claiming “no harm will result to the general population, including infants and children, from aggregate exposure to fludioxonil residues,” the previous findings suggest that the chemical can cause more potential to harm non-fungal cells than previously thought.
The solicitude over chemical exposure from pesticides and human health is hardly a new issue as a plethora of studies demonstrates the risks associated with toxic chemical exposure. Specific concerns arise over fungicides like fludioxonil as its ubiquitous use in agricultural and residential settings puts human and animal health at risk. Furthermore, studies regarding climate change note that changes to moisture and temperature conditions promote the spread of fungi as global warming may cause fungi to become significantly more heat-tolerant. Heat-tolerant fungi not only increase pesticides use to combat spread but also increases fungi’s ability to infect a host with higher body temperatures as the difference between environmental and body temperature will decrease. Additionally, extreme weather conditions associated with climate change like flooding from hurricanes, or drought, can promote fungus growth, specifically mold, resulting in more extensive fungicides use.
Exposure to fungicides can manifest various adverse health effects, including reproductive dysfunction, birth/developmental effects, kidney/liver damage, and cancer. Furthermore, some researchers suggest excessive use of fungicides can promote more drug-resistant fungal infections in humans as these fungicides are structurally similar to medical antifungal medications. In addition to containing potentially dangerous compounds, fungicide use in agriculture is often in conjunction with other chemical pesticides to increase potency. However, the synergy between fungicides and other pesticides can further worsen the adverse effect of chemical exposure has on human and animal health. Since humans and animals encounter these pesticides through a wide variety of applications, it is essential to understand how these chemicals work to cause toxicity in humans and animals.
Although previous studies report that fludioxonil disrupts hepatic (liver), endocrine, and neurological systems, the mode of action by which this fungicide causes these issues only recently came to light. According to research by Dr. Brandhorst, fludioxonil may impede the antioxidant glutathione from protecting the body from illnesses while prompting disease endurance. This research adds to previous reports which associate glutathione disruption and oxidation with fludioxonil exposure. Glutathione is a natural antioxidant important in blood pressure and glucose regulation, preventing the formation of free radicals which damage cells in hypertension and diabetes mellitus. However, the endocrine disruption properties of fludioxonil can cause intracellular glutathione deficiency resulting in oxidative stress that influences the development of diseases, including Alzheimer’s disease, liver disease, cancer, diabetes, and more. A decrease in glutathione biosynthesis and/or an increase in depletion of the intracellular glutathione pool can impair oxidation-reduction homeostasis and promote oxidative stress that may account for individual susceptibility to a disease like COVID-19.
An observational study of COVID-19 patients in Russia finds that many of the patients already have a glutathione deficiency that makes them susceptible to COVID-19. However, Dr. Brandhorst warns that the mechanism by which fludioxonil damages cells is not singular, but multifactorial, damaging cells in a variety of ways. Since fludioxonil decreases glutathione levels, world leaders must limit exposure to this fungicide to mitigate the severity of disease prevalence among vulnerable individuals.
The Environmental Protection Agency’s (EPA) registration of fludioxonil came with the assumption that the absence of an enzyme in one group of organisms protects the overall health of all other organisms. However, EPA mistakenly made a similar assumption in assessing glyphosate/Roundup, which caused it to ignore the impacts of that herbicide on the human gut microbiota. Although EPA considers a wide range of potential health risks from pesticides, there is no requirement to assess glutathione depletion from a pesticide since “it does not kill you” but “makes you weak,” according to Dr. Brandhorst. If these research results are replicated then, “all this work done [by EPA] to prove that fludioxonil is safe is invalid.”
As the U.S. COVID-19 cases continue to rise, world leaders must establish policies that manage viral and bacterial infections, without exacerbating the risk to both animals and humans in the process of avoiding or controlling the threat. In the case of COVID-19, we have measures of protection—both practices and products—that can prevent infection without using toxic products that increase risk factors. Additionally, the negative impacts on human and environmental health from pesticide use include the mounting resistance issues thatdemonstrate the ineffectiveness of pest management in chemical-intensive agriculture. Individuals and government officials alike should assess all risks associated with pesticide use, including chronic risk from chemical depletion in the body. Advocates maintain that EPA must have a complete understanding of the mode of action of any pesticide it registers and should include as a part of its registration review new information in the peer-reviewed scientific literature. EPA’s failure to respond to current science is viewed as a major shortcoming of its risk assessment process.
It is essential that when EPA weighs the risks and benefits of pesticide use it does not allow harm to those disproportionally affected by these chemicals—people of color, including essential workers and farm and landscape workers, who may suffer elevated exposure to the virus. An evaluation of the contribution of pesticide use and exposure to health outcomes of COVID-19 is urgently needed. To learn more about how the lack of adequate regulations of pesticide use, including fungicides, can impact human and environmental health, see Beyond Pesticides’ Pesticides and You article “Highly Destructive Pesticide Effects Unregulated.” Additionally, Beyond Pesticides advocates for a precautionary approach to pest management in land management and agriculture, with a transition to organic methods. Lastly, learn how to protect yourself from COVID-19 safely by visiting Beyond Pesticides’ webpage on Disinfectants and Sanitizers for more information.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: E&E News
