Some wayward ticks delayed a United Airlines flight.

Flight 1178 was delayed for nearly six hours on Tuesday after a passenger informed a flight attendant that she found a tick -- which is an insect that can carry diseases, such as Rocky Mountain spotted fever and Lyme disease -- in economy class during a flight to Denver.

The airline decided it couldn't fly the plane, which was scheduled next to go from Denver to Des Moines, Iowa, until it was cleaned of ticks. So passengers had to wait while another plane was flown in.

United spokeswoman Robin Urbanski said that up to three ticks were discovered. Urbanski said the airline hasn't figured out how the ticks got on the plane or what type of ticks were found.

The plane with ticks had begun its day in Chicago. It was cleaned of ticks, checked and put back into service.