Two airport workers in Germany die after contracting malaria in a rare workplace outbreak that officials link to a mosquito arriving on an aircraft, according to multiple reports. BBC and other outlets say five additional airport employees are receiving medical treatment.

The infections occur at Germany’s busiest airport, as described by BBC, with figures ranging between four and six cases reported at different times as new information becomes available. The reports cite Germany’s Robert Koch Institute, which says the most likely cause is an imported Anopheles mosquito carried in on an aircraft. CBS and other outlets also note that malaria is caused by parasites spread via Anopheles mosquitoes and can become serious without prompt treatment.

While outlets agree on the core facts—deaths, the suspected mosquito-on-plane link, and the Anopheles identification—some differ on early case counts and how quickly they were updated. Several sources also describe measures being taken by the airport, such as monitoring or trapping, in response to the outbreak.