Climate change and vector-borne diseases

Abstract

Vector-borne diseases (VBD), such as Zika, dengue, chikungunya, yellow fever, leishmaniasis, malaria, Rift Valley Fever, Lyme disease and bluetongue are transmitted by exothermic arthropod vectors such as mosquitoes, flies, midges and ticks that do not regulate their internal temperature. Precipitation provides breeding sites for the early larval stages of the vectors, while temperature modulates their development, mortality rate and the time required for the pathogen to replicate in their body. As a consequence, climate change in addition to an ever-increasing mobility of goods and people and other socio-economic risk factors, will very likely affect the distribution of vector-borne diseases in future. Coupling mathematical disease models with climate observations and ensemble of future climate change scenarios, allow to explore potential future changes in VBD distribution and assess related uncertainties. This presentation will review research carried out at the University of Liverpool in collaboration with several international partners over the past decade. Our work confirmed the impact of the 2006 heatwave on the emergence of bluetongue, a midge-borne disease affecting ruminants, into northern Europe. In 2011 another publication anticipated the northward spread of Aedes albopictus, the Asian tiger mosquito, in Europe and into southern UK. In a study published in 2014 we showed that malaria risk could increase over tropical altitude regions while it could decrease over the warmer regions during the 2080s under the most extreme RCP8.5 scenario. In 2017, a study showed that the climatic conditions related to the 2015 El Niño event favoured the Zika outbreak that had a large impact on Latin America that year. Many other research groups anticipated the spread of vectors and the diseases they can transmit worldwide. This fact demonstrates the value and usefulness of such predictive risk models; and importantly that we need to take urgent measures to tackle anthropogenic climate change.