The man was suffering from fever and took treatment at a corporate hospital here, but was referred to the state-run Gandhi Hospital.
"As per the definition of WHO, he is not a suspect also. Nigeria is already declared as Ebola free by WHO on October 19," said Dr K Subhakar, the nodal officer for infectious diseases like Ebola.
"This person has come from Nigeria. He was screened at Mumbai airport. (He had) no symptoms and he came to Hyderabad by domestic flight. After four days, he developed a fever. Because he came from African countries, they have come to Gandhi (hospital). We want to be more cautious," he said.
The fever has also come down, though the patient is kept in isolation, he said.
The government is taking all necessary measures against the spread of Ebola and has put in an elaborate procedure for checking and screening of air travellers.