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What is West Nile virus and how climate change may affect its spread - The Washington Post

The Washington Post · last updated

What is West Nile virus and how climate change may affect its spread - The Washington Post

The West Nile virus is more commonly contracted in warmer climates, where hot and tropical temperatures allow the mosquitoes that carry it to thrive. Health experts are increasingly concerned that climate change could worsen the spread of the virus in less common places — and even bring it to new ones.

Climate change may worsen spread of West Nile virus: What to know

The virus, which is the leading cause of mosquito-borne disease in the continental United States, is particularly dangerous during mosquito season, starting in the summer through fall. “The number of West Nile virus-infected mosquitoes we’ve detected this season is the highest we’ve seen in years,” said Colorado’s state epidemiologist, Rachel Herlihy.

For most people, the virus causes no serious illness and requires no treatment. However, in about 1 in 150 cases, it can lead to serious infections of the brain and nervous system. Here’s what to know.

Related Knowledge Center: Climate science

State of Play

What began as a theory in the 1890s — that industrial emissions of carbon dioxide could increase global temperatures — had progressed to a scientific fact a century later. Scientists across a range of disciplines are studying the impact of the still-growing concentration of carbon dioxide and other so-called “greenhouse gases” in the atmosphere as they call for industrial and governmental policies to slow, then halt, the warming of the planet. 

More informationabout Climate science