The Effect of Climate Change on the Distribution and Incidence of Uk Parasitic Disease

There is a strong consensus that climate change is occurring (Trenberth, 2005) and as it is at least partly attributable to green house gas emissions from human activity, further warming can be expected to occur (Bernardi, 2008). Some parasites of veterinary and zoonotic significance in the UK are unlikely to be affected by global warming. Toxocara spp. are ubiquitous and transmitted primarily by transplacental and transmammary routes and as a result are shielded from environmental changes. Others, such as tapeworms are transmitted through the ingestion of meat and offal from domestic livestock, with the intermediate host being largely unaffected by gradual changes in climate, due to protection from the farming environment. Other parasites, however, depend heavily on warmth and humidity to reproduce, feed and survive. Recent mild winters and wet summers have likely played a part in Angiostrongylus vasorum's spread across the UK, introducing it into areas where veterinary professionals and pet owners may not recognise it as a differential in dogs presenting with a cough, coagulopathy or neurological signs. Prolonged periods of high humidity have increased the length of time that Ixodes spp. ticks can quest for, seeking food and increasing the risk of exposure to Lyme disease. Fleas have also benefitted from consecutive mild winters, allowing increased numbers of fleas to survive outdoors without having to rely purely on centrally heated homes to maintain their numbers over winter. This article will consider these examples of parasites that climate is already affecting and how veterinary nurses should be prepared to adapt their parasite control advice accordingly.