(CNN) It had already become the world's biggest cholera outbreak in recent history, but now the number of suspected cholera cases in Yemen since April has hit 1 million, and at an incredibly fast speed.

The International Committee of the Red Cross announced the record Thursday on its official Twitter account Thursday, describing it as "shocking."

"More than 80% of the population lack food, fuel, clean water and access to health care," it said, pointing to some of the underlying causes of the disease.

Cholera is an acute diarrheal illness that kills thousands of people worldwide each year. It is easily transmitted, by consuming food or water contaminated with the fecal bacteria Vibrio cholerae.

Yemen's civil war that began in 2015 has left millions of people on the brink of famine, and as clean drinking water becomes harder to find, cholera has spread through communities.

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