Hamburg's central station was blocked for several hours due to an alarm about a suspected case of Marburg hemorrhagic fever.
The alarm concerned two Germans who had returned home after visiting Rwanda, where at least six people have died in an outbreak of the disease.
The two Germans, a medical student and his girlfriend, are believed to have come into contact with a man who was later confirmed to be infected.
The two Germans arrived in Frankfurt on Wednesday and continued by train to Hamburg. During the train journey, they are said to have displayed "flu-like" symptoms. They have now been taken to an infectious diseases clinic for further testing.
According to Bild, around 200 train passengers are at risk of infection and will be interviewed and possibly tested.
Marburg is similar to Ebola and has a mortality rate of up to 88 percent. The course of the disease is rapid and sudden, with high fever, severe headache, and nausea. In a later stage, the infected person may start bleeding in the skin and internal organs.
