Scanning electron microscope image of the underside of a tick

Just a tick

Modelling of tick ecology can pinpoint areas at risk of tick-borne diseases

Ticks spread a range of diseases, including Lyme disease and a viral infection of the brain, tick-borne encephalitis. Where they live depends on climate factors such as temperature and rainfall.

But as well as shifting their range, climate change will also affect their life cycle, moving seasonal peaks of infection. This is significant as ticks only bite hosts at certain stages of their life cycle.

Other factors may have bigger effects – such as changing land use, which affects the numbers of tick-carrying animals, or leisure activities: more forest leisure areas will increase human exposure to ticks.

Without a satisfactory model, predicting the effects of climate change is very difficult. Only continuous monitoring is likely to give a clearer picture of trends.

On the other hand, tick-borne encephalitis is seen only in part of the range of ticks, in central Europe and parts of eastern Europe. These areas support a particular style of tick life cycle, which is associated with a specific type of climate – hot summers, rapid cooling in autumn and reasonable rainfall.

These factors can be modelled and the impact of climate change assessed. Although some spread is possible (some cases have been reported in Sweden and Finland in 2014), tick-borne encephalitis is unlikely to reach the UK.

Lead image:

Scanning electron micrograph of the ventral surface of a castor bean tick (Ixodes ricinus), computer-coloured brown on green, showing serrated mouthparts, abdomen and claws. This ectoparasite is a vector of Lyme disease.

David Gregory and Debbie Marshall/Wellcome Images CC BY NC ND


About this resource

This resource was first published in ‘Health and Climate Change’ in January 2009 and reviewed and updated in September 2014.

Statistics and maths, Ecology and environment, Health, infection and disease
Health and Climate Change
Education levels:
14–16, 16–19, Continuing professional development