Multiple passengers fell ill on two separate international flights coming into Philadelphia International Airport on Thursday, reports CBS Philly:

Officials say 12 passengers arriving at the airport on American Airlines flights from Paris and Munich experienced flu-like symptoms. Multiple ambulances were dispatched to the airport.

All 250 passengers and crew on the flights were held for a medical review and the Centers for Disease Control and Prevention was notified to investigate.

The CDC, Philadelphia Health Department and the Philadelphia Fire Department personnel performed medical evaluations on the passengers.

In a statement, the CDC said,

“CDC is aware of two American Airlines flights from Paris and Germany that arrived at PHL airport this afternoon with ill passengers on board. CDC and Philadelphia public health officers worked with EMS and CBP officials to evaluate and test the ill passengers for influenza and other respiratory illnesses. Twelve passengers from the two flights reported sore throat and cough; none were identified with fever. None of the passengers are severely ill, and they will be released and informed of test results in 24 hours.”

Just yesterday, a flight from Dubai was quarantined at John F. Kennedy Airport in New York after as many as 100 passengers reported feeling ill and were said to have coughs and high fevers. At least 19 people were confirmed to be ill – 10 of which were taken to the hospital. The remaining 9 refused medical attention.

Some of the passengers on yesterday’s flight reportedly had been in Mecca, Saudi Arabia, where there is currently an active flu outbreak.

And, several of the sick passengers on the two American Airlines flights that were briefly quarantined today also were returning from Mecca, according to NBC Philadelphia:

Several of the sick passengers were returning from pilgrimages to Mecca, Saudi Arabia, on American Airlines flight 755, which originated in Paris. These travelers exhibited similar symptoms to the 19 passengers, also travelling from Mecca, who were quarantined in New York Wednesday morning, according to customs officials.

Additional passengers Philadelphia-bound American Airlines flight 717 from Munich, Germany, also showed flu-like symptoms. They, too, were returning from Mecca.

Flu outbreaks have occurred in the past following the annual pilgrimage to Mecca during Hajj, officials said.

Multiple news outlets have reported that more than one million religious observers flocked to the holy city this year. However, it is unclear how many caught the flu.

As we reported yesterday, hopefully this is not the beginning of a pandemic flu outbreak. It may be wise to prepare accordingly, just in case.