Climate Change and Rising Food-Borne Illnesses: A Growing Concern
In mid-February, parts of India witnessed a surge in cases of Guillain-Barré syndrome (GBS), a nerve disorder that can cause pain, paralysis, and difficulties in breathing and swallowing. The outbreak was first reported in Maharashtra at the end of January and later in Andhra Pradesh in February. Experts suspect a stomach bug to be the cause.
As of February 19, Maharashtra had recorded over 211 cases and 11 deaths, while Andhra Pradesh reported 17 cases and two deaths. The World Health Organization (WHO) states that the exact cause of GBS is unknown, but it often follows a bacterial or viral infection. One of the primary culprits is Campylobacter jejuni, a bacteria that causes gastroenteritis and can trigger an immune response that attacks the nervous system.
Climate Change and the Spread of Food-Borne Illnesses
Professor Siara Rao Ajjampur from the Christian Medical College, Vellore, suggests that Campylobacter jejuni is the likely cause of this outbreak. Seasonal spikes in GBS have been observed before, often linked to winter when respiratory infections and flu cases rise. Previous GBS outbreaks in French Polynesia, Latin America (2013–2016), and Peru (2019) were associated with Zika virus and Campylobacter jejuni infections, respectively.
Scientists are now investigating whether climate change—especially extreme temperatures and flooding—may be contributing to the spread of food-borne microbes like Campylobacter, Salmonella, and E. coli. Data from India has been included in global studies examining the link between rising temperatures and bacterial outbreaks.
Ajjampur explains that climate change affects bacterial survival strategies and human behavior, including food and water consumption habits. Campylobacter bacteria, though difficult to culture in labs, can survive in harsh environments by forming protective biofilms. Studies indicate they can persist in well water for extended periods, particularly in colder temperatures.
Scientific Findings on Climate and Food-Borne Pathogens
A December 2024 report in One Health highlighted the rise in climate-related food-borne diseases. It reviewed global research on how climate factors—rainfall, storms, humidity, and temperature—affect the spread of pathogens like Campylobacter, Salmonella, and Listeria. The study found that climate change is also worsening antimicrobial resistance (AMR), making infections harder to treat.
Approximately 30% of Campylobacter infections in humans come from poultry, 20–30% from beef, and others from game animals. Temperature and humidity fluctuations affect Campylobacter levels in chicken flocks, while human infections often correlate with extreme weather events.
A study from Ontario, Canada, found a direct link between climate and bacterial prevalence. Another 2024 report from The Lancet Discovery showed that for every 1°C rise in temperature, the risk of Salmonella and Campylobacter infections increased by 5%.
The European Climate and Health Observatory warned in 2023 that warmer, wetter climates with extreme events could increase bacterial growth and human exposure to pathogens. A 2021 Lancet Regional Health report found that many food-borne bacteria can survive in harsh conditions, with Campylobacter showing strong associations with rising temperatures and climate variability.
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Future Risks and Public Health Concerns
A 2020 study by researchers in Denmark, Finland, Norway, and Sweden estimated that climate change alone could lead to an extra 145 cases of Campylobacter infections annually by 2040 and nearly 1,500 additional cases per year by the 2080s in each of these countries. The study linked these increases to higher temperatures and precipitation, indicating a potential non-food transmission route.
Researchers caution that climate change could significantly impact food safety and public health. Understanding local and regional effects is crucial for developing preventive strategies.
Water Quality and Bacterial Survival
Other studies have examined how water quality affects Campylobacter outbreaks. A 2021 Czech Republic study found that Campylobacter jejuni and C. coli levels in water were influenced by ammonium and chloride ion concentrations, which could help predict future outbreaks.
Similarly, a 2012 Finnish study showed that C. jejuni’s survival is temperature-dependent, affecting its potential to cause waterborne infections. With antimicrobial resistance rising, scientists stress the importance of monitoring water sources and food chains to prevent future outbreaks.
Conclusion
With climate change altering environmental conditions, food-borne illnesses are becoming a growing concern. Rising temperatures, extreme weather, and changing human behaviours contribute to spreading dangerous bacteria. Understanding these links and taking proactive public health measures will be crucial in mitigating future risks and protecting communities from outbreaks like the recent GBS cases in India.
This article was initially published in Mongabay
