Climate change is reshaping the delicate balance between pathogenic bacteria and their microscopic enemies, exemplified by the complex relationship between the bacterium Burkholderia pseudomallei and its phages. These phages, or bacterial viruses, play a pivotal role in controlling bacterial populations, yet rising temperatures and agricultural practices could alter their effectiveness dramatically.
Recent research employing mathematical modelling has illuminated the potential dangers posed by climate change to the dynamics of B. pseudomallei, which is responsible for melioidosis — a severe illness increasingly prevalent across Southeast Asia, particularly Thailand. This bacterium poses significant health risks, contributing to thousands of fatalities annually. The study focuses on the temperature-dependent life cycles of phages, highlighting how they can either promote or inhibit bacterial growth depending on environmental conditions.
The study's authors utilized historical data from Thailand covering the years 2009 to 2023 and projected potential outcomes for the next two decades. Through simulations based on the principles of temperature dependence and UV radiation impacts, they discovered troubling trends. Specifically, the modelling projected significant increases in the densities of phage-free B. pseudomallei due to climate factors, which could lead to higher risks of infection for agricultural workers.
The model's predictions are sobering, particularly as it indicates a potential increase in the prevalence of melioidosis, especially during the hotter months when bacterial populations tend to burgeon. This idea is especially concerning for agricultural workers who are exposed to these pathogens during rice planting and harvesting seasons, which coincide with periods of higher temperature and potentially problematic interactions with phages. Therefore, the authors stress the importance of enhancing protective measures during these peak periods to minimize exposure to the deadly pathogen.
Key findings from the modelling include the assertion: “An increase in the average annual temperature should result in a corresponding increase in the amount of phage-free susceptible bacteria... presenting the main risk of melioidosis acquisition by humans.” This highlights the importance of maintaining the natural phage populations, which typically keep bacterial densities under control.
To make their predictions more accurate, researchers incorporated real-world data on UV radiation, which directly affects phage survivability. The conclusions were alarming: “The pathogenic bacteria will reach its carrying capacity and will be out of natural control by the phage.” This indicates the risk posed to public health — as phage control wanes due to environmental stressors, bacterial populations could swing out of balance, exacerbated by climate-related changes.
Given the intertwined fates of bacteria and the phages, the research effectively advocates for cautious agricultural practices. The careful management of agrochemicals, especially those harmful to phages, is necessary to maintain the bacteriophage populations and, by extension, natural controls over B. pseudomallei growth.
Looking forward, the study highlights the pressing need for strategic adjustments to agricultural practices, especially under warming conditions to protect agricultural workers and populations at risk. By doing so, it offers insights on maintaining ecological balance and safeguarding public health from the ever-increasing threats posed by climate change.