West Nile virus, valley fever, hantavirus: Over the past decade, the West has seen an increase in some rare but scary illnesses. According to a September study in the American Journal of Tropical Medicine and Hygiene, the U.S. places 11th globally for incidents of plague. Scientists also recently discovered that a deadly tropical fungus, which first appeared in the Pacific Northwest roughly a decade ago, has moved further into the U.S.

Worldwide, many tropical and subtropical diseases are spreading, thanks to climate change, biodiversity loss and easy global travel. Pathogen-carrying pests like mosquitoes thrive in warmer, wetter conditions, while biodiversity declines give diseases easier access to their preferred hosts.

Scientists know little about some of the West’s nastiest diseases — except that they are becoming more common. Some are easily dodged (avoid mouse droppings that might carry hantavirus); others are more insidious (lung fungus spreads easily through the air). Here are more facts about some strange — and alarming — Western diseases.

This article appeared in the print edition of the magazine with the headline The fungus among us.

Spread the word. News organizations can pick-up quality news, essays and feature stories for free.

Creative Commons License

Republish our articles for free, online or in print, under a Creative Commons license.