An Italian man who has been confirmed as Nigeria’s first coronavirus case after arriving from Milan was in the country for almost two full days, traveling through Lagos and visiting another state before being isolated.

The case is the first in sub-Saharan Africa. Authorities fear the virus could spread quickly in a region where health systems are already overburdened with cases of malaria, measles, Ebola and other infectious diseases.

Lagos, with 20 million people, is the biggest city in Nigeria, Africa’s most populous country. The West African country, with a population of some 200 million people, has a shortage of doctors and hospitals are often poorly maintained.

The Italian man works for cement company Lafarge Africa in the southwestern state of Ogun, the company said in a statement. It said it had identified people who had “direct contact” with him before carrying out “isolation, quarantine and disinfection protocol.”

The Ogun state governor, in a separate media briefing, said 28 people had been placed in quarantine by the company the man worked for, although he did not mention it by name.

The case has prompted a scramble by Nigerian authorities to try to “meet and observe” all passengers who arrived on the same flight as the man and to identify the places he visited before being hospitalised.

“We have started working to identify all the contacts of the person since he entered Nigeria and even those who were with him on the aircraft,” Health Minister Osagie Ehanire told reporters on Friday in the capital, Abuja.

In this video, Nigeria confirms its first case of coronavirus in Lagos state, southwest of the country.