Infectious diseases with changing climate

Climate change alters environmental conditions, and facilitates the proliferation of arthropod disease vectors such as ticks and mosquitoes.

The number of arthropod associated illnesses have more than doubled. 

Multiple pathogens, such as West Nile and Zika viruses have been identified that were not previously common in the US. 

It is known that tick survival over winter months increases with a shorter, milder winters. 

This leads to larger populations and a more northern extension of their geographic locations. 

Longer summers result in a longer period of time when ticks bites create opportunities to spread diseases, such as babedsiosis, anaplasmosis, and Lyme disease. 

Mosquitoes have a shorter lifespan than ticks.

Mosquitoes require water to breed and increased precipitation alters the size and location of local mosquito populations. 

Increased temperatures increase the efficiency of mosquito breeding cycle and females require more blood to support multiple gestations over their lifetime. 

Warmer temperatures have promoted the northern extension of the location of pathogen carrying mosquito species: Aedes aegypti the primary vector for dengue, yellow fever, and Zika viruses.

Anopheles mosquitoes that transfer malaria have also increased.

Zoonotic infections that spread between humans and other vertebrate animals and that may be viral, bacterial, or parasitic are also altered by climate change dynamics and behaviors of host animals increasing spread of such diseases.

Changes in precipitation and temperatures can affect food availability, population size and behavior of rodents that can pass plague and hanta virus diseases. 

These climate changes result in increased incidence in geographical shift northward into higher altitudes.

More than half of the earth’s animal species have undergone climate change alterations of their natural habitat, with many moving northward and declines in global southern areas.

Altered climate causes habitat destruction, causing numerous species to come into close contact, and increasing the risk of pathogens spreading to other species, potentially including humans. 

Migratory birds are affected by habitat, destruction, and are  the cause of current global outbreak of avian influenza. 

H5N1 has been detected in all 50 states in the United States and more than 7500 birds promote species transmission in multiple mammal species. 

Zoonotic diseases are increased by globalization, changes in land-use, deforestation, human migration, and international travel.

Only approximately 300 fungi infect humans, as one of the primary resistance barriers to fungal pathogens is that they are unable to grow at elevated temperatures.

With climate changes, fungal organisms develop tolerance to the warming environment, and the temperature differential between humans and the environment is narrowing, increasing the number of fungal infections and new pathogens: Candida, auris, and Sporothrix brasiliensis.

Coccidioides is expanding northern and easterly.

Histoplasmosis has been documenting in more northern and eastern locations.

Sea level rising influences, approximately 40% of US individuals living in coastal areas. 

Sea level events combined with warming temperatures increases contact with coastal pathogens which causes gastroenteritis, soft tissue infections, and sepsis, the latter with mortality rates up to 50%.

Water pathogens such as Vibrio species, Campylobacter, Escherichia coli, and cryptosporidium cause diarrheal disease is after flooding, and are worsening with weather events in warm climates.


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