Two Frankfurt Airport workers have died from malaria following a rare outbreak that has infected six employees at Germany’s busiest airport.

The outbreak was first detected in July, with German public health officials believing the mosquitoes responsible may have arrived at the airport aboard a plane. A spokesperson for airport operator Fraport confirmed that an employee had died from the infection, while Frankfurt public health officials later announced that two of the affected workers had died.

The six infected workers are all men who worked in different roles and areas of the airport. Authorities are examining blood samples to determine whether the infections came from a single mosquito or from multiple mosquitoes.

Mosquito traps have been installed across the airport, with captured insects being sent to laboratories to establish their species and origin. “We have provided comprehensive information to all employees and encourage them to consult a doctor if they experience any symptoms,” a Fraport spokesperson said.

The Frankfurt Public Health Department is investigating the outbreak, while laboratory tests aimed at identifying the precise source of the infections are expected to take several weeks. Officials have stressed that the risk to the general population remains extremely low.

“For the population of Frankfurt, the risk is considered very, very low. The disease is not transmissible from person to person but is always transmitted by mosquitoes,” Frankfurt public health officials said in a letter to media outlets.

The outbreak was initially reported in July when four airport workers were known to have contracted malaria. The Robert Koch Institute said the four employees became ill between July 4 and 6 and had no recent travel history, supporting the theory that the mosquitoes were brought into Germany by aircraft. Malaria infections in Germany are normally associated with people who have travelled to countries where the disease is endemic. The Robert Koch Institute said transmission within a German airport is extremely rare.

“The lack of a travel history can lead to a delayed diagnosis. A delayed diagnosis increases the risk of a severe course of the diseases,” the institute said in its epidemiological bulletin. The institute also noted that the last recorded case of airport-transmitted malaria in Germany occurred at Frankfurt Airport in 2023.

Malaria is caused by parasites transmitted through the bites of infected mosquitoes and is predominantly found in tropical regions, according to the World Health Organization. The disease is both preventable and curable, but infections can range from mild symptoms to potentially life-threatening illness.