Even bed bugs take public transportation in New York City.
Metropolitan Transportation Authority officials have found bed bugs on four separate N-line trains, MTA spokesman Kevin Ortiz told CNBC.
Officials also discovered the bugs in two crew locker rooms in Astoria, he said.
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All of the trains have been fumigated, and are now back in service, but the MTA is doing "continuous spot checks," he said.
Bed bugs were first discovered on an N-line train over the weekend, WABC-TV reported on Wednesday. At the time of that report, only three train infestations had been discovered and remedied.
—By CNBC staff