People infected with Powassan virus can develop serious neurological symptoms.
A mysterious disease affecting young Californian black bears is causing them to become fearless when interacting with humans and is preventing them from developing properly.
Most people bitten by a West Nile virus mosquito won't get sick, but in a small percentage of people, the virus invades the brain and spinal cord, which results in serious illness.
The Eastern equine encephalitis virus is spread by mosquitoes and, in rare cases, can lead to a life-threatening brain infection.
A flight attendant in Israel is in a coma after getting the measles, according to news reports.
At least 10 people in India have died from a rare virus known as Nipah virus, according to news reports.
The man had a mysterious infection in his brain, but tests for dozens of viruses and bacterial infections came back negative.
A newborn baby in Iowa died this week from an infection with the virus that causes cold sores, which she likely contracted from a kiss, her doctors say.
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