![]() ![]() ![]() ![]() TDR and the World Health Organization are gathering evidence that climate change influences the geographical distribution of insects and affects the transmission of vector-borne diseases. The changes can also impact humans by prompting them to leave, or by affecting agricultural practices and housing systems. ![]() These environments may become more or less favourable to the vectors and to disease transmission. Finally, during its next bloodmeal for mosquitoes, flies and ticks, but also through other means such as defecating for bugs or being squashed for lice, the vector transmits the pathogen into another host.Ĭhanges in temperature and precipitation affect the environment in which the VBDs are transmitted. The time required for the amplification of the pathogen in the insect is called the extrinsic incubation period (EIP). Then, the pathogen develops within the insect and acts as an infectious vector when transmitting the pathogen to a non-immune host. Insects may become infectious mainly after the ingestion of a pathogen through a bloodmeal on an infected host – for example, when a mosquito bites a sick human. Hosts can be humans or livestock or other animals that become infected and eventually sick after being infected by a vector. Vectors can be mosquitoes, flies, ticks or other insect species that transmit the pathogen to a host. Pathogens can be parasites, viruses or bacteria that cause infections either silent or symptomatic in humans and/or animals. koya979/Ī vector-borne disease involves three elements: the pathogen, the vector, and the host. For this reason, TDR and WHO are gathering evidence on how climate change influences the geographical distribution of these insects and subsequently affects the transmission of VBDs. Although great progress has been achieved in the past century on the control of these infectious diseases, the environmental changes are compromising the progress and a deeper understanding of these diseases is needed. Every year, VBDs cause more than 700,000 deaths. Malaria, Zika virus, dengue, chikungunya, yellow fever, Japanese encephalitis, Lyme disease, typhus, leishmaniasis and sleeping sickness are examples of VBDs. Among these species are insects such as mosquitoes, ticks and flies that can transmit illnesses called vector-borne diseases (VBDs). This prompts species to move to more favourable regions. With climate changes, however, a suitable region can become unsuitable for specific species while, on the contrary, an unsuitable region can become suitable. Extreme events such as cyclones and floods have also become more frequent.Īverage weather conditions greatly influence wildlife as plant and animal species live in regions that offer suitable conditions: while some species thrive in tropical regions, temperate or continental conditions will be more adapted to others. Over the past fifty years, Earth’s climate has been affected by global warming: surface, air and ocean temperature has been increasing, resulting in the melting of glaciers and the rise of sea levels. Climate changes occur naturally at different timescales, from tens to thousands of years, though factors such as human activity can modify these changes. The climate of each region is defined by averages over many years of temperature, precipitation, wind and other weather-related parameters. Dr Florence Fouque, researcher at the World Health Organization, is passionate about understanding the effects of climate and environmental factors including climate change on the transmission of vector-borne diseases.Īround the globe, climate differs from one region of the world to another. This can prove to be problematic for local human populations as some of these insects carry diseases: vector-borne diseases are illnesses caused by parasites, viruses and bacteria that are transmitted by vectors such as mosquitoes, ticks and flies. These changes may cause insect displacements to regions that are more favourable to them. Climate change is responsible for changes in temperature and rainfall patterns as well as more frequent extreme events such as floods. ![]()
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