SPECIAL REPORT
Diseases love climate change Climate change could cause more food-borne disease outbreaks that threaten our food chain. Samantha Tennent reports.
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OOD safety is being threatened by climate change directly and indirectly putting public health at risk from foodborne diseases, experts say. Primarily, it happens with increases in extreme events, increases in air and water temperatures and changes to rain frequency and intensity. World Health Organisation nutrition and food safety technical officer Carmen Savelli recently spoke about climate change and food-borne diseases at the digital World Veterinary Congress. “It’s estimated 600 million people are getting sick from unsafe food each year. “Which translates to one in 10 people getting sick and 420,000 of those people die. “This could increase with the effects of climate change,” Savelli says. There are many complex systems related to climate change that will affect foodborne diseases including the growth range and survival of pathogens and other micro-organisms in the food chain that could have an impact on crops, livestock and the environment. The increases in water temperature can lead to increased rates of bacterial growth in water and with sediments already present convert mercury into methylmercury, which then accumulates in the food chain and gets into fish. Methylmercury is highly toxic and can lead to a range of health problems. Higher water temperatures also correlate to an increase in the frequency and extent of algal blooms. The rapid growth of algae can harm animals, people and ecology. Toxins released by algal bloom can accumulate in fish and shellfish and if humans ingest even a small amount of contaminated seafood they can experience serious health problems. Another water-related problem is the increase in rain and flooding, which can move pathogens through the environment and contaminate crops and livestock facilities. “When animal and plant agriculture are in relative proximity it’s not hard to
DAIRY FARMER
July 2020
Change can increase events such as floods, which can move pathogens through the environment and contaminate food sources like crops, which in turn contaminate livestock.
imagine how increased precipitation leading to flooding can lead to contamination of irrigation water, for example. “On the flip side, during droughts contaminated dirt blowing into the fields as dust particles is also a possibility.” Another indirect way climate change can cause food-borne disease is through increased activity, range, expansion and reproduction rates of wildlife carrying diseases, which can change contamination patterns and lead to foodborne disease. “Produce like lettuce or strawberries or other fruits or vegetables are generally grown in rural areas. Wildlife, such as deer, which are known carriers of human pathogens like E coli, readily intrude on crops and can be responsible for contamination and illness events.” Savelli says. “Fortunately, mitigating the healthrelated impacts of climate change is both possible and necessary. Globally, health authorities in collaboration with their partners, agriculture, environment and other relevant sectors, will need to be able to prevent, detect and manage the increased food-borne risks that are going
Climate change will provide several ways food-borne diseases can spread more easily, World Health Organisation food safety technical officer Carmen Savelli says.
to be associated with climate change. “They will need to do so in a way that advances health equity and ensures that no one is left behind.” There needs to be improvement in monitoring and surveillance of foodborne diseases and enhancement of emergency preparedness response and capacity-building to better be able to prevent and manage the threat from increased food-borne risks that are going to be associated with climate change. “Climate change is a global problem and it is going to take a global effort to overcome the challenges we are facing. There will need to be better information sharing.” n
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