Vectors also transmit diseases and viruses to animals with damaging consequences for livestock and wildlife. Biting midges of the Culicoides genus are carriers of bluetongue, a viral disease affecting sheep, goats, cattle and deer. There is evidence that the midges advanced northwards into southern Europe from Africa as a result of increased humidity and temperature linked to global warming. The movement of blood-feeding flies, mosquitoes and ticks are responsible for the spread of lumpy skin disease from the Middle East to south-east Europe. Temperature and humidity are key factors in the abundance of these vectors and the risk of its further spread.

In our work on bee health, EFSA scientists initiated efforts to develop a model to assess risks to honeybee colonies from exposure to pesticides under different scenarios of combined stressors and drivers, including the influence of climate on the honey bee colony. The model will help to clarify the relative importance of different stressors, e.g. how does the impact of a pesticide on colony health change with changing climate. The collection of data (including climate data) is accompanying the model development.

Diseases

The transmission of infections or diseases between animals and humans (“zoonotic diseases”) is a major source of food safety risks. Environmental factors such as temperature, rainfall, humidity levels and soil can help to explain the distribution and survival of bacteria such as Salmonella and Campylobacter. The presence of norovirus (“the winter vomiting bug”) in oysters from sewage runoffs caused by heavy rainstorm and flooding may also linked to the increasing frequency of extreme weather events due to climate change.

Contaminants

EFSA’s assessments of environmental contaminants includes several naturally occurring toxins produced by fungi and plankton. Increases in the presence of these toxins and/or their appearance in new geographical locations has been linked to climate change in some cases.

Certain species of fungi produce chemicals called mycotoxins, some of which can be highly toxic. They can affect the health of infected plants and enter the food chain via contaminated food and feed crops (cereals, legumes, nuts). Temperature and humidity are important factors influencing fungal growth, crop infection and mycotoxin toxicity . Climate change is considered a driver of recent changes in the occurrence of mycotoxins in Europe.

For example, aflatoxins are carcinogenic mycotoxins produced by two species of Aspergillus, a fungus found in areas with hot and humid climates. Rising temperatures and humidity linked to climate change probably contributed to the appearance of aflatoxins in southern Europe in the early 2000s and their steady spread northwards since then. In 2012 EFSA helped to develop a tool for predicting the production and spread of aflatoxins in maize, wheat and rice under different climate change scenarios. Also, mycotoxins often occur in nature in mixtures, potentially interacting and increasing the risks for animals and humans. Our scientists are supporting research to help develop flexible risk assessment modelling approaches for mycotoxin mixtures. This includes studying the impact of environmental variables related to climate change (e.g. temperature, pest attack, nutrient availability) on mycotoxins production and their occurrence in food.

Climatic variables also have a huge impact on the presence of phytoplankton. These microscopic marine and freshwater algae are a mainstay of the diet of many fish and other marine life. Some of them, however, can be highly toxic and lead to seafood poisoning. One of them is ciguatera, typically present in tropical areas. Since 2008, several outbreaks of ciguatera fish poisoning have occurred in Spain (Canary Islands) and in Portugal (Madeira) with climate change a likely cause. EFSA is supporting national partners who are collecting data on environmental factors (temperature rises, increased salinity) affecting the toxicity of ciguatera and developing models to predict blooming, accumulation in fish and future outbreaks using different climate scenarios. Also, an increase in indigenous marine bacteria such as Vibrio that can produce toxins in molluscs may be due to rising sea water and temperatures.

Cyanobacteria are naturally forming bacteria that bloom on fresh and seawater surfaces. They boast a range of nutritional properties and are used as ‘natural’ food supplements. However, some have toxic properties that are expected to multiply due to global warming and other environmental factors such as nutrient availability.