Climate change can possibly alter entire ecosystem habitats. When habitats are no longer suitable for living, many vector hosts, such as birds, will shift migration patterns or move to a more suitable living area. Changes in residence of these animals can increase rate of transmission of a disease or bring the disease to a new area.

University of California, Davis

Climate is a important factor that determines the rate of transmission of a disease. Changes in climate can lead to:
- Geographic shifts of vector and reservoirs
- Changes in rates of development, survival, reproduction of vectors, reservoirs, and pathogens

Such changes can lead to an increase in transmission and expansion of diseases in to other regions.


Climate and Vector Borne Diseases

Rocklöv, Joacim, and Robert Dubrow. Climate Change: An Enduring Challenge for Vector-Borne Disease Prevention and Control. 20 Apr. 2020, www.nature.com/articles/s41590-020-0648-y. 

Climate change: an enduring challenge for vector-borne disease prevention and control

Most arthropods are ectotherms, which are organism in which internal physiological sources of heat are of relatively small. Therefore, when temperature increases, vector abundance, survival, and feeding activity will also increase. 

Temperature Increase and Vectors

Water plays an important role in many arthropods' reproductive cycle. Many lays their eggs in stagnant water. Therefore, increased precipitation can lead to more breeding sites, as rainwater will pool up near human residences and roads. However, extreme drought can also provide more breeding sites due to an increase in containers to store rainwater, which are stagnant.

Precipitation and Vectors

Climate Change and Vector Hosts

Since climate change affects the abundance and survival of a vector and possibly increase the incidences of a disease, it will have many public health consequences such as:
- Time lag between changes to climate that makes a non-endemic area endemic, actual establishment of vector and pathogen, reports of cases.
- pathogen/vector evolution accelerates due to higher replication rate, thus  impacting disease emergence, re-emergence, and spread
- wide socioeconomic impacts, increase in health inequities, decline of  socioeconomic development
- Can overwhelm healthcare systems and other sectors like tourism



Public Health Consequences and Climate Change

Natural disasters such as cyclones and flooding may increase the number of vectors. Although breeding sites may be initially washed away, standing water caused by heavy rainfall will create new breeding sites, thus increasing the vector population. The risk of disease transmission will also increase due to:
- crowding of infected and susceptible hosts
- a weakened public health infrastructure
- interruptions of ongoing control programs 

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