A day after an Emirates plane was quarantined at New York JFK Airport, two more inbound flights were held at Philadelphia International Airport due to several passengers falling ill.
Officers from the Centers for Disease Control and Prevention were once again called after a combined 12 passengers traveling from Paris and Munich became ill.
Both flights were operated by American Airlines.
"This afternoon, 12 passengers arriving at Philadelphia International Airport on international flights on American Airlines from Paris and on American Airlines from Munich were experiencing flu-like symptoms," airport management said in a statement.
"As a precaution, all passengers on the two flights – totaling about 250 plus crew – were held for a medical review and the CDC was notified."
The CDC said all the passengers displayed flu-like symptoms.
"None of the passengers are severely ill, and they will be released and informed of test results in 24 hours," the agency said.
The US Customs and Border Protection told NBC Philadelphia all the affected passengers had originated from Mecca in Saudia Arabia which has had a flu outbreak.
The CDC also said passengers on the Emirates flight a day earlier also tested positive for the flu.
The jet carrying them had made a prior stop in Mecca before flying to New York.
Referring to the Emirates passengers, the CDC said: "For the 11 individuals taken to the hospital, preliminary tests indicate that some patients tested positive for influenza and/or other common respiratory viruses."
