Climate change and mosquito borne pathogens and parasites

Over recent months, much of the media commentary has been focussed on the Zika virus (transmitted by mosquito bites) and its potential to affect the Olympic Games to be held in Rio de Janeiro between 5th and 21st August 2016.  The increasing risk of serious vector-borne disease is much greater that most periodic media reports would suggest and more so with the increasing impact of climate change. The main risks, which to a limited extent, are already realised involve pathogens and parasites such as Malaria and Dengue fever (from Mosquitoes), Sandfly fever and Leishmaniasis (from Sand Flies) and Lyme Disease and Encephalitis (from Ticks) all of which have the potential to have an expanded geographic range due to warmer weather. The increased temperatures enable the transmitting insects to travel further afield than is currently the case moving into areas that previously were free of disease. Dengue fever, for example, is found in a band between the Tropic of Cancer and the Tropic of Capricorn and not fully across the entire region. Warmer weather will enable this range to expand in both North and South latitudes. Dengue cases have already been increasing from 0.5m in 1990 to almost 2.7M by 2013. The projected increase in future years is 12-18% by 2030 and vaccines are only in the very early stages of developmnent. Malaria has now been detected in higher altitude regions of Papua New Guina where there was no previous exposure. Public health authorities have only just started to grasp the scale of this on-the-horizon issue and the threat to health may yet prove to have a significant impact on outdoor living activities.