The New York Metropolitan Transit Authority (MTA) has fumigated three subway trains from the N line after discovering a number of unwanted passengers - namely bed bugs.

Two trains were initially taken out of service on Sunday after MTA officials discovered Cimex lectularius, the common bed bug, in a number of cars. MTA spokesman Kevin Ortiz wouldn't say where on the trains the bugs were found, nor would he say at which point in the line they were discovered.

However, unnamed sources told the NY Daily News that the pests were found primarily in train cab seat cushions used by conductors and motormen, and are less likely to have spread to passengers.

Still, this is no small worry. According to the United States Environmental Protection Agency (EPA), bed bugs are a notoriously difficult-to-rid public health pest. Unlike most health pests, C. lectularius is not known to commonly carry disease. Though, they are still extremely hearty, and can develop resistances to standard pesticides. Some people may also have severe allergic reactions to the tiny blood-suckers' bite, but this is very rare.

Ortiz told local news stations via email that as of Tuesday, a third train was also taken from the N line to be fumigated.

"The MTA continues to spot check other crew and passenger areas," he said. "They say this is isolated [and] no crew members or passengers have reported bites by the bedbugs."

Still, according to the EPA it would be hard to spot bedbug bites, which are small and draw very little blood. If given a chance to reproduce and bite again in a new setting (say, a home), MTA passengers might soon start reporting itching and skin irritation.

This is why the EPA and the Centers for Disease Control and Prevention (CDC) recommend that potentially exposed residents conduct thorough checks of their hair, clothing, bedding, and even car upholstery, to ensure that these little train passengers haven't found themselves a new ride.