Tick Summary - HECC Chapter 8: climate and vector-borne diseases
Chapter 8 of the HECC report examines how climate change may have an impact on ticks and tick-borne diseases, potentially changing associated public health risk.
Applies to England
CCHS navigation menu:
CCHS homepage
Topic: health impacts
Vector-borne disease: ticks
Part of: learning about ticks
Key resources for HECC chapter 8:
-
Tick summary chapter 8: climate and vector-borne diseases
- Chapter 8 full report (pdf)
More content:
Summary
Vector-borne diseases (VBDs) are illnesses caused when parasites, viruses or bacteria are spread to humans and animals by blood-feeding arthropods (vectors), which include mosquitoes, ticks, midges, sand-flies and fleas. The presence, distribution and seasonality of vectors, as well as the pathogens they carry, are influenced by both weather and climate. This chapter of the Health Effects of Climate Change (HECC) report describes how the public health risk posed by vector-borne diseases could change in the UK under a high warming scenario.
The UK has over 20 native species of tick, which are influenced by microclimate, habitat and hosts as well as human behaviour, and there has been a Tick Surveillance Scheme (TSS) in place since 2005.
Ixodes ricinus is a tick species which is native to the UK and has been found to have increased numbers and a wider distribution over time. This presents a risk to public health because Ixodes ricinus can transmit Lyme disease and tick-borne encephalitis (TBE). While the incidence of Lyme disease is low in the UK, it increased between 2001 and 2018. It is difficult to determine how much of this due to climate change, however. Initiatives to increase biodiversity in woodland areas through planting trees, for example, is likely to increase habitat availability for ticks and their hosts. Similarly, the expansion of urban areas into greenbelts amongst tick habitats, can also increase exposure to ticks.
Another tick species that is native to the UK is Dermacentor reticulatus, and its expansion in the UK has been attributed to several factors including climate change, land use changes, travel patterns of humans and animals, and host availability. Finally, Haemaphysalis punctata is a native species which can survive in hot, dry conditions. Currently there are no studies exploring the effect of weather or climate change on this species and changes in distribution of this species so far, have been attributed to host movements.
Hyalomma marginatum is a non-native tick species with a preference for hot and dry conditions. Individual ticks have been detected in the UK previously, but it is too cold for them to survive. With warmer temperatures, there could be an increase in the years where this species can survive, however modelling under a high warming scenario suggests that autumn temperatures in the UK are still likely to be too low for this species to reach adulthood. Another invasive species of tick, Rhipicephalus sanguineus, has been associated with travellers or dogs who have been abroad. There is evidence that its biting rate increases with warmer temperatures.
Once a non-native species has become established, it is very difficult to eradicate it. Surveillance is therefore very important for identifying the presence of new species early enough to remove them.